diff --git a/packages/@ember/-internals/glimmer/tests/integration/components/attrs-lookup-test.js b/packages/@ember/-internals/glimmer/tests/integration/components/attrs-lookup-test.js
index 631b532e336..451f7734ecd 100644
--- a/packages/@ember/-internals/glimmer/tests/integration/components/attrs-lookup-test.js
+++ b/packages/@ember/-internals/glimmer/tests/integration/components/attrs-lookup-test.js
@@ -171,9 +171,7 @@ moduleFor(
         }
       };
 
-      FooBarComponent.reopenClass({
-        positionalParams: ['firstPositional'],
-      });
+      FooBarComponent.positionalParams = ['firstPositional'];
 
       this.owner.register('component:foo-bar', FooBarComponent);
 
diff --git a/packages/@ember/routing/tests/location/history_location_test.js b/packages/@ember/routing/tests/location/history_location_test.js
index 68505a5a3ec..e5b992957fe 100644
--- a/packages/@ember/routing/tests/location/history_location_test.js
+++ b/packages/@ember/routing/tests/location/history_location_test.js
@@ -68,15 +68,16 @@ moduleFor(
     ['@test HistoryLocation initState does not get fired on init'](assert) {
       assert.expect(1);
 
-      HistoryTestLocation.reopen({
+      HistoryTestLocation = class extends HistoryTestLocation {
         init() {
           assert.ok(true, 'init was called');
-          this._super(...arguments);
-        },
+          super.init(...arguments);
+        }
+
         initState() {
           assert.ok(false, 'initState() should not be called automatically');
-        },
-      });
+        }
+      };
 
       createLocation();
     }
@@ -93,7 +94,7 @@ moduleFor(
         createLocation();
         location.initState();
 
-        assert.strictEqual(location.get('baseURL'), '/foo/');
+        assert.strictEqual(location.baseURL, '/foo/');
       } finally {
         document.head.removeChild(base);
       }
@@ -111,7 +112,7 @@ moduleFor(
         createLocation();
         location.initState();
 
-        assert.strictEqual(location.get('baseURL'), '');
+        assert.strictEqual(location.baseURL, '');
       } finally {
         document.head.removeChild(base);
       }
@@ -120,20 +121,20 @@ moduleFor(
     ['@test base URL is removed when retrieving the current pathname'](assert) {
       assert.expect(1);
 
-      HistoryTestLocation.reopen({
+      HistoryTestLocation = class extends HistoryTestLocation {
         init() {
-          this._super(...arguments);
+          super.init(...arguments);
 
           set(this, 'location', mockBrowserLocation('/base/foo/bar'));
           set(this, 'baseURL', '/base/');
-        },
+        }
 
         initState() {
-          this._super(...arguments);
+          super.initState(...arguments);
 
           assert.equal(this.getURL(), '/foo/bar');
-        },
-      });
+        }
+      };
 
       createLocation();
       location.initState();
@@ -142,14 +143,14 @@ moduleFor(
     ['@test base URL is preserved when moving around'](assert) {
       assert.expect(2);
 
-      HistoryTestLocation.reopen({
+      HistoryTestLocation = class extends HistoryTestLocation {
         init() {
-          this._super(...arguments);
+          super.init(...arguments);
 
           set(this, 'location', mockBrowserLocation('/base/foo/bar'));
           set(this, 'baseURL', '/base/');
-        },
-      });
+        }
+      };
 
       createLocation();
       location.initState();
@@ -184,15 +185,15 @@ moduleFor(
     ['@test HistoryLocation.getURL() returns the current url, excluding both rootURL and baseURL'](
       assert
     ) {
-      HistoryTestLocation.reopen({
+      HistoryTestLocation = class extends HistoryTestLocation {
         init() {
-          this._super(...arguments);
+          super.init(...arguments);
 
           set(this, 'location', mockBrowserLocation('/base/foo/bar'));
           set(this, 'rootURL', '/app/');
           set(this, 'baseURL', '/base/');
-        },
-      });
+        }
+      };
 
       createLocation();
 
@@ -202,14 +203,14 @@ moduleFor(
     ['@test HistoryLocation.getURL() returns the current url, does not remove rootURL if its not at start of url'](
       assert
     ) {
-      HistoryTestLocation.reopen({
+      HistoryTestLocation = class extends HistoryTestLocation {
         init() {
-          this._super(...arguments);
+          super.init(...arguments);
 
           set(this, 'location', mockBrowserLocation('/foo/bar/baz'));
           set(this, 'rootURL', '/bar/');
-        },
-      });
+        }
+      };
 
       createLocation();
 
@@ -219,13 +220,13 @@ moduleFor(
     ['@test HistoryLocation.getURL() will not remove the rootURL when only a partial match'](
       assert
     ) {
-      HistoryTestLocation.reopen({
+      HistoryTestLocation = class extends HistoryTestLocation {
         init() {
-          this._super(...arguments);
+          super.init(...arguments);
           set(this, 'location', mockBrowserLocation('/bars/baz'));
           set(this, 'rootURL', '/bar/');
-        },
-      });
+        }
+      };
 
       createLocation();
 
@@ -235,14 +236,14 @@ moduleFor(
     ['@test HistoryLocation.getURL() returns the current url, does not remove baseURL if its not at start of url'](
       assert
     ) {
-      HistoryTestLocation.reopen({
+      HistoryTestLocation = class extends HistoryTestLocation {
         init() {
-          this._super(...arguments);
+          super.init(...arguments);
 
           set(this, 'location', mockBrowserLocation('/foo/bar/baz'));
           set(this, 'baseURL', '/bar/');
-        },
-      });
+        }
+      };
 
       createLocation();
 
@@ -252,13 +253,13 @@ moduleFor(
     ['@test HistoryLocation.getURL() will not remove the baseURL when only a partial match'](
       assert
     ) {
-      HistoryTestLocation.reopen({
+      HistoryTestLocation = class extends HistoryTestLocation {
         init() {
-          this._super(...arguments);
+          super.init(...arguments);
           set(this, 'location', mockBrowserLocation('/bars/baz'));
           set(this, 'baseURL', '/bar/');
-        },
-      });
+        }
+      };
 
       createLocation();
 
@@ -266,12 +267,12 @@ moduleFor(
     }
 
     ['@test HistoryLocation.getURL() includes location.search'](assert) {
-      HistoryTestLocation.reopen({
+      HistoryTestLocation = class extends HistoryTestLocation {
         init() {
-          this._super(...arguments);
+          super.init(...arguments);
           set(this, 'location', mockBrowserLocation('/foo/bar?time=morphin'));
-        },
-      });
+        }
+      };
 
       createLocation();
 
@@ -279,12 +280,12 @@ moduleFor(
     }
 
     ['@test HistoryLocation.getURL() includes location.hash'](assert) {
-      HistoryTestLocation.reopen({
+      HistoryTestLocation = class extends HistoryTestLocation {
         init() {
-          this._super(...arguments);
+          super.init(...arguments);
           set(this, 'location', mockBrowserLocation('/foo/bar#pink-power-ranger'));
-        },
-      });
+        }
+      };
 
       createLocation();
 
@@ -292,12 +293,12 @@ moduleFor(
     }
 
     ['@test HistoryLocation.getURL() includes location.hash and location.search'](assert) {
-      HistoryTestLocation.reopen({
+      HistoryTestLocation = class extends HistoryTestLocation {
         init() {
-          this._super(...arguments);
+          super.init(...arguments);
           set(this, 'location', mockBrowserLocation('/foo/bar?time=morphin#pink-power-ranger'));
-        },
-      });
+        }
+      };
 
       createLocation();
 
@@ -305,14 +306,14 @@ moduleFor(
     }
 
     ['@test HistoryLocation.getURL() drops duplicate slashes'](assert) {
-      HistoryTestLocation.reopen({
+      HistoryTestLocation = class extends HistoryTestLocation {
         init() {
-          this._super(...arguments);
+          super.init(...arguments);
           let location = mockBrowserLocation('//admin//profile//');
           location.pathname = '//admin//profile//'; // mockBrowserLocation does not allow for `//`, so force it
           set(this, 'location', location);
-        },
-      });
+        }
+      };
 
       createLocation();
 
@@ -322,14 +323,14 @@ moduleFor(
     ['@test HistoryLocation.getURL() treats regex metacharacters in rootURL and baseURL literally'](
       assert
     ) {
-      HistoryTestLocation.reopen({
+      HistoryTestLocation = class extends HistoryTestLocation {
         init() {
-          this._super(...arguments);
+          super.init(...arguments);
           set(this, 'location', mockBrowserLocation('/axc/secret'));
           set(this, 'rootURL', '/a.c/');
           set(this, 'baseURL', '/a.c/');
-        },
-      });
+        }
+      };
 
       createLocation();
 
@@ -344,12 +345,12 @@ moduleFor(
 
       FakeHistory.state = existingState;
 
-      HistoryTestLocation.reopen({
+      HistoryTestLocation = class extends HistoryTestLocation {
         init() {
-          this._super(...arguments);
+          super.init(...arguments);
           set(this, 'location', mockBrowserLocation('/route/path'));
-        },
-      });
+        }
+      };
 
       createLocation();
       location.initState();
diff --git a/packages/@ember/routing/tests/location/none_location_test.js b/packages/@ember/routing/tests/location/none_location_test.js
index 04f77db057b..ca1091f6d89 100644
--- a/packages/@ember/routing/tests/location/none_location_test.js
+++ b/packages/@ember/routing/tests/location/none_location_test.js
@@ -29,12 +29,12 @@ moduleFor(
     }
 
     ['@test NoneLocation.formatURL() returns the current url always appending rootURL'](assert) {
-      NoneTestLocation.reopen({
+      NoneTestLocation = class extends NoneTestLocation {
         init() {
-          this._super(...arguments);
+          super.init(...arguments);
           set(this, 'rootURL', '/en/');
-        },
-      });
+        }
+      };
 
       createLocation();
 
@@ -42,13 +42,13 @@ moduleFor(
     }
 
     ['@test NoneLocation.getURL() returns the current path minus rootURL'](assert) {
-      NoneTestLocation.reopen({
+      NoneTestLocation = class extends NoneTestLocation {
         init() {
-          this._super(...arguments);
+          super.init(...arguments);
           set(this, 'rootURL', '/foo/');
           set(this, 'path', '/foo/bar');
-        },
-      });
+        }
+      };
 
       createLocation();
 
@@ -58,13 +58,13 @@ moduleFor(
     ['@test NoneLocation.getURL() will remove the rootURL only from the beginning of a url'](
       assert
     ) {
-      NoneTestLocation.reopen({
+      NoneTestLocation = class extends NoneTestLocation {
         init() {
-          this._super(...arguments);
+          super.init(...arguments);
           set(this, 'rootURL', '/bar/');
           set(this, 'path', '/foo/bar/baz');
-        },
-      });
+        }
+      };
 
       createLocation();
 
@@ -72,13 +72,13 @@ moduleFor(
     }
 
     ['@test NoneLocation.getURL() will not remove the rootURL when only a partial match'](assert) {
-      NoneTestLocation.reopen({
+      NoneTestLocation = class extends NoneTestLocation {
         init() {
-          this._super(...arguments);
+          super.init(...arguments);
           set(this, 'rootURL', '/bar/');
           set(this, 'path', '/bars/baz');
-        },
-      });
+        }
+      };
 
       createLocation();
 
@@ -86,13 +86,13 @@ moduleFor(
     }
 
     ['@test NoneLocation.getURL() treats regex metacharacters in rootURL literally'](assert) {
-      NoneTestLocation.reopen({
+      NoneTestLocation = class extends NoneTestLocation {
         init() {
-          this._super(...arguments);
+          super.init(...arguments);
           set(this, 'rootURL', '/a.c/');
           set(this, 'path', '/axc/secret');
-        },
-      });
+        }
+      };
 
       createLocation();
 
@@ -100,13 +100,13 @@ moduleFor(
     }
 
     ['@test NoneLocation.getURL() strips the rootURL when it has an extra trailing slash'](assert) {
-      NoneTestLocation.reopen({
+      NoneTestLocation = class extends NoneTestLocation {
         init() {
-          this._super(...arguments);
+          super.init(...arguments);
           set(this, 'rootURL', '/foo//');
           set(this, 'path', '/foo//bar');
-        },
-      });
+        }
+      };
 
       createLocation();
 
diff --git a/packages/@ember/routing/tests/system/dsl_test.js b/packages/@ember/routing/tests/system/dsl_test.js
index 5b7d63df119..1d502629f3c 100644
--- a/packages/@ember/routing/tests/system/dsl_test.js
+++ b/packages/@ember/routing/tests/system/dsl_test.js
@@ -87,11 +87,7 @@ moduleFor(
         this.route('blork');
       });
 
-      this.routerInstance.reopen({
-        _hasModuleBasedResolver() {
-          return true;
-        },
-      });
+      this.routerInstance._hasModuleBasedResolver = () => true;
 
       let router = this.routerInstance;
       router._initRouterJs();
@@ -133,11 +129,7 @@ moduleFor(
         });
       });
 
-      this.routerInstance.reopen({
-        _hasModuleBasedResolver() {
-          return true;
-        },
-      });
+      this.routerInstance._hasModuleBasedResolver = () => true;
 
       let router = this.routerInstance;
       router._initRouterJs();
@@ -285,11 +277,7 @@ moduleFor(
         this.mount('chat');
       });
 
-      this.routerInstance.reopen({
-        _hasModuleBasedResolver() {
-          return true;
-        },
-      });
+      this.routerInstance._hasModuleBasedResolver = () => true;
       this.routerInstance._initRouterJs();
       let router = this.routerInstance;
       assert.ok(router._routerMicrolib.recognizer.names['chat'], 'main route was created');
@@ -304,11 +292,7 @@ moduleFor(
         this.mount('chat', { as: 'shoutbox' });
       });
 
-      this.routerInstance.reopen({
-        _hasModuleBasedResolver() {
-          return true;
-        },
-      });
+      this.routerInstance._hasModuleBasedResolver = () => true;
       this.routerInstance._initRouterJs();
       let router = this.routerInstance;
 
@@ -351,11 +335,7 @@ moduleFor(
         });
       });
 
-      this.routerInstance.reopen({
-        _hasModuleBasedResolver() {
-          return true;
-        },
-      });
+      this.routerInstance._hasModuleBasedResolver = () => true;
       this.routerInstance._initRouterJs();
       let router = this.routerInstance;
 
diff --git a/packages/@ember/utils/tests/compare_test.js b/packages/@ember/utils/tests/compare_test.js
index 36c107bd826..9d1ef5be7b7 100644
--- a/packages/@ember/utils/tests/compare_test.js
+++ b/packages/@ember/utils/tests/compare_test.js
@@ -4,13 +4,11 @@ import { moduleFor, AbstractTestCase, expectDeprecation, testUnless } from 'inte
 import { DEPRECATIONS } from '@ember/-internals/deprecations';
 
 let data = [];
-let Comp = EmberObject.extend();
-
-Comp.reopenClass({
-  compare(obj) {
+class Comp extends EmberObject {
+  static compare(obj) {
     return obj.get('val');
-  },
-});
+  }
+}
 
 const UTILS = DEPRECATIONS.DEPRECATE_EMBER_UTILS;
 
diff --git a/packages/@ember/utils/tests/type_of_test.js b/packages/@ember/utils/tests/type_of_test.js
index c1739a7ae48..7f778b2f7dc 100644
--- a/packages/@ember/utils/tests/type_of_test.js
+++ b/packages/@ember/utils/tests/type_of_test.js
@@ -46,6 +46,7 @@ moduleFor(
       assert.equal(typeOf(instance.method), 'function', 'item of type function');
       assert.equal(typeOf(instance.asyncMethod), 'function', 'item of type async function');
       assert.equal(typeOf(EmberObject.extend()), 'class', 'item of type class');
+      assert.equal(typeOf(class extends EmberObject {}), 'class', 'item of type native class');
       assert.equal(typeOf(new Error()), 'error', 'item of type error');
     }
 
diff --git a/packages/ember/tests/routing/decoupled_basic_test.js b/packages/ember/tests/routing/decoupled_basic_test.js
index c404f8dcd88..3fb495f1ce9 100644
--- a/packages/ember/tests/routing/decoupled_basic_test.js
+++ b/packages/ember/tests/routing/decoupled_basic_test.js
@@ -5,7 +5,7 @@ import { precompileTemplate } from '@ember/template-compilation';
 import Route from '@ember/routing/route';
 import NoneLocation from '@ember/routing/none-location';
 import HistoryLocation from '@ember/routing/history-location';
-import EmberObject, { set } from '@ember/object';
+import { set } from '@ember/object';
 import {
   moduleFor,
   ApplicationTestCase,
@@ -140,9 +140,13 @@ moduleFor(
 
       let menuItem, resolve;
 
-      let MenuItem = class extends EmberObject {
+      let MenuItem = class {
+        constructor(id) {
+          this.id = id;
+        }
+
         static find(id) {
-          menuItem = MenuItem.create({ id: id });
+          menuItem = new MenuItem(id);
 
           return new RSVP.Promise(function (res) {
             resolve = res;
@@ -185,7 +189,7 @@ moduleFor(
         this.route('special', { path: '/specials/:menu_item_id' });
       });
 
-      let MenuItem = class extends EmberObject {
+      let MenuItem = class {
         static find(id) {
           return { id: id };
         }
@@ -267,9 +271,13 @@ moduleFor(
 
       let menuItem, resolve;
 
-      let MenuItem = class extends EmberObject {
+      let MenuItem = class {
+        constructor(id) {
+          this.id = id;
+        }
+
         static find(id) {
-          menuItem = MenuItem.create({ id: id });
+          menuItem = new MenuItem(id);
           return new RSVP.Promise((res) => (resolve = res));
         }
       };
@@ -322,7 +330,7 @@ moduleFor(
         let urlSetCount = 0;
         let router = this.applicationInstance.lookup('router:main');
 
-        router.get('location').setURL = function (path) {
+        router.location.setURL = function (path) {
           urlSetCount++;
           set(this, 'path', path);
         };
@@ -335,7 +343,7 @@ moduleFor(
         });
 
         assert.equal(urlSetCount, 1);
-        assert.equal(router.get('location').getURL(), '/bar');
+        assert.equal(router.location.getURL(), '/bar');
       });
     }
 
@@ -361,19 +369,23 @@ moduleFor(
     ['@test using replaceWith calls location.replaceURL if available'](assert) {
       let setCount = 0;
       let replaceCount = 0;
-      this.router.reopen({
-        location: NoneLocation.create({
-          setURL(path) {
-            setCount++;
-            set(this, 'path', path);
-          },
-
-          replaceURL(path) {
-            replaceCount++;
-            set(this, 'path', path);
-          },
-        }),
-      });
+      this.subclass(
+        'router:main',
+        (Router) =>
+          class extends Router {
+            location = NoneLocation.create({
+              setURL(path) {
+                setCount++;
+                set(this, 'path', path);
+              },
+
+              replaceURL(path) {
+                replaceCount++;
+                set(this, 'path', path);
+              },
+            });
+          }
+      );
 
       this.router.map(function () {
         this.route('root', { path: '/' });
@@ -389,21 +401,25 @@ moduleFor(
 
         assert.equal(setCount, 1, 'should not call setURL');
         assert.equal(replaceCount, 1, 'should call replaceURL once');
-        assert.equal(router.get('location').getURL(), '/foo');
+        assert.equal(router.location.getURL(), '/foo');
       });
     }
 
     ['@test using replaceWith calls setURL if location.replaceURL is not defined'](assert) {
       let setCount = 0;
 
-      this.router.reopen({
-        location: NoneLocation.create({
-          setURL(path) {
-            setCount++;
-            set(this, 'path', path);
-          },
-        }),
-      });
+      this.subclass(
+        'router:main',
+        (Router) =>
+          class extends Router {
+            location = NoneLocation.create({
+              setURL(path) {
+                setCount++;
+                set(this, 'path', path);
+              },
+            });
+          }
+      );
 
       this.router.map(function () {
         this.route('root', { path: '/' });
@@ -416,7 +432,7 @@ moduleFor(
         assert.equal(setCount, 1);
         run(() => router.replaceWith('foo'));
         assert.equal(setCount, 2, 'should call setURL once');
-        assert.equal(router.get('location').getURL(), '/foo');
+        assert.equal(router.location.getURL(), '/foo');
       });
     }
 
@@ -501,7 +517,7 @@ moduleFor(
         let router = this.applicationInstance.lookup('router:main');
         this.handleURLAborts(assert, '/foo/bar/baz');
         assert.equal(router.currentPath, 'home');
-        assert.equal(router.get('location').getURL(), '/home');
+        assert.equal(router.location.getURL(), '/home');
       });
     }
 
@@ -600,7 +616,7 @@ moduleFor(
         this.handleURLAborts(assert, '/foo/bar/1/baz');
         assert.equal(this.appRouter.currentPath, 'foo.bar.baz');
         assert.equal(
-          this.applicationInstance.lookup('router:main').get('location').getURL(),
+          this.applicationInstance.lookup('router:main').location.getURL(),
           '/foo/bar/2/baz'
         );
       });
@@ -638,7 +654,7 @@ moduleFor(
         assert.equal(router.currentPath, 'foo.bar.baz');
         run(() => router.send('goToQux'));
         assert.equal(router.currentPath, 'foo.qux');
-        assert.equal(router.get('location').getURL(), '/foo/qux');
+        assert.equal(router.location.getURL(), '/foo/qux');
       });
     }
 
@@ -648,7 +664,7 @@ moduleFor(
       let setHistory;
 
       setHistory = function (obj, path) {
-        obj.set('history', { state: { path: path } });
+        set(obj, 'history', { state: { path: path } });
       };
 
       let location = HistoryLocation.create({
@@ -656,7 +672,7 @@ moduleFor(
           let path = rootURL + '/posts';
 
           setHistory(this, path);
-          this.set('location', {
+          set(this, 'location', {
             pathname: path,
             href: 'http://localhost/' + path,
           });
@@ -671,11 +687,15 @@ moduleFor(
         },
       });
 
-      this.router.reopen({
-        // location: 'historyTest',
-        location,
-        rootURL: rootURL,
-      });
+      this.subclass(
+        'router:main',
+        (Router) =>
+          class extends Router {
+            location = location;
+
+            rootURL = rootURL;
+          }
+      );
 
       this.router.map(function () {
         this.route('posts', { path: '/posts' });
@@ -711,24 +731,28 @@ moduleFor(
             pushState() {},
           };
           initState() {
-            assert.equal(this.get('rootURL'), rootURL);
+            assert.equal(this.rootURL, rootURL);
           }
         }
       );
 
-      this.router.reopen({
-        location: 'history-test',
-        rootURL: rootURL,
-        // if we transition in this test we will receive failures
-        // if the tests are run from a static file
-        _doURLTransition() {
-          return {
-            followRedirects() {
-              return RSVP.resolve('');
-            },
-          };
-        },
-      });
+      this.subclass(
+        'router:main',
+        (Router) =>
+          class extends Router {
+            location = 'history-test';
+
+            rootURL = rootURL;
+
+            _doURLTransition() {
+              return {
+                followRedirects() {
+                  return RSVP.resolve('');
+                },
+              };
+            }
+          }
+      );
 
       return this.visit('/');
     }
@@ -1105,7 +1129,7 @@ moduleFor(
 
       return this.visit('/').then(() => {
         let router = this.applicationInstance.lookup('router:main');
-        assert.equal(router.get('location.path'), '/about/TreeklesMcGeekles');
+        assert.equal(router.location.path, '/about/TreeklesMcGeekles');
       });
     }
 
diff --git a/packages/ember/tests/routing/query_params_test/model_dependent_state_with_query_params_test.js b/packages/ember/tests/routing/query_params_test/model_dependent_state_with_query_params_test.js
index c369825e7c9..64246d3bb41 100644
--- a/packages/ember/tests/routing/query_params_test/model_dependent_state_with_query_params_test.js
+++ b/packages/ember/tests/routing/query_params_test/model_dependent_state_with_query_params_test.js
@@ -1,7 +1,7 @@
 import Controller from '@ember/controller';
 import { A as emberA } from '@ember/array';
 import Route from '@ember/routing/route';
-import { computed } from '@ember/object';
+import { set } from '@ember/object';
 import { precompileTemplate } from '@ember/template-compilation';
 import { QueryParamTestCase, moduleFor, runLoopSettled } from 'internal-test-helpers';
 
@@ -18,14 +18,6 @@ class ModelDependentQPTestCase extends QueryParamTestCase {
       'there should be no pending expectation of expected model hook params'
     );
   }
-
-  reopenController(name, options) {
-    this.application.resolveRegistration(`controller:${name}`).reopen(options);
-  }
-
-  reopenRoute(name, options) {
-    this.application.resolveRegistration(`route:${name}`).reopen(options);
-  }
 }
 
 moduleFor(
@@ -69,19 +61,22 @@ moduleFor(
 
       this.add(
         'controller:article',
-        Controller.extend({
-          queryParams: ['q', 'z'],
-          q: 'wat',
-          z: 0,
-        })
+        class extends Controller {
+          queryParams = ['q', 'z'];
+
+          q = 'wat';
+
+          z = 0;
+        }
       );
 
       this.add(
         'controller:comments',
-        Controller.extend({
-          queryParams: 'page',
-          page: 1,
-        })
+        class extends Controller {
+          queryParams = ['page'];
+
+          page = 1;
+        }
       );
 
       this.add(
@@ -133,9 +128,9 @@ moduleFor(
       this.$link2.click();
       await runLoopSettled();
 
-      assert.equal(this.controller.get('q'), 'wat');
-      assert.equal(this.controller.get('z'), 0);
-      assert.deepEqual(this.controller.get('model'), { id: 'a-2' });
+      assert.equal(this.controller.q, 'wat');
+      assert.equal(this.controller.z, 0);
+      assert.deepEqual(this.controller.model, { id: 'a-2' });
       assert.equal(this.$link1.getAttribute('href'), '/a/a-1?q=lol');
       assert.equal(this.$link2.getAttribute('href'), '/a/a-2');
       assert.equal(this.$link3.getAttribute('href'), '/a/a-3');
@@ -151,9 +146,9 @@ moduleFor(
 
       await this.transitionTo('/a/a-1?q=lol');
 
-      assert.deepEqual(this.controller.get('model'), { id: 'a-1' });
-      assert.equal(this.controller.get('q'), 'lol');
-      assert.equal(this.controller.get('z'), 0);
+      assert.deepEqual(this.controller.model, { id: 'a-1' });
+      assert.equal(this.controller.q, 'lol');
+      assert.equal(this.controller.z, 0);
       assert.equal(this.$link1.getAttribute('href'), '/a/a-1?q=lol');
       assert.equal(this.$link2.getAttribute('href'), '/a/a-2');
       assert.equal(this.$link3.getAttribute('href'), '/a/a-3');
@@ -162,13 +157,9 @@ moduleFor(
 
       await this.transitionTo('/a/a-2?q=lol');
 
-      assert.deepEqual(
-        this.controller.get('model'),
-        { id: 'a-2' },
-        "controller's model changed to a-2"
-      );
-      assert.equal(this.controller.get('q'), 'lol');
-      assert.equal(this.controller.get('z'), 0);
+      assert.deepEqual(this.controller.model, { id: 'a-2' }, "controller's model changed to a-2");
+      assert.equal(this.controller.q, 'lol');
+      assert.equal(this.controller.z, 0);
       assert.equal(this.$link1.getAttribute('href'), '/a/a-1?q=lol');
       assert.equal(this.$link2.getAttribute('href'), '/a/a-2?q=lol');
       assert.equal(this.$link3.getAttribute('href'), '/a/a-3');
@@ -177,8 +168,8 @@ moduleFor(
 
       await this.transitionTo('/a/a-3?q=lol&z=123');
 
-      assert.equal(this.controller.get('q'), 'lol');
-      assert.equal(this.controller.get('z'), 123);
+      assert.equal(this.controller.q, 'lol');
+      assert.equal(this.controller.z, 123);
       assert.equal(this.$link1.getAttribute('href'), '/a/a-1?q=lol');
       assert.equal(this.$link2.getAttribute('href'), '/a/a-2?q=lol');
       assert.equal(this.$link3.getAttribute('href'), '/a/a-3?q=lol&z=123');
@@ -204,9 +195,9 @@ moduleFor(
       this.expectedModelHookParams = { id: 'a-1', q: 'wat', z: 0 };
       await this.transitionTo('article', 'a-1');
 
-      assert.deepEqual(this.controller.get('model'), { id: 'a-1' });
-      assert.equal(this.controller.get('q'), 'wat');
-      assert.equal(this.controller.get('z'), 0);
+      assert.deepEqual(this.controller.model, { id: 'a-1' });
+      assert.equal(this.controller.q, 'wat');
+      assert.equal(this.controller.z, 0);
       assert.equal(this.$link1.getAttribute('href'), '/a/a-1');
       assert.equal(this.$link2.getAttribute('href'), '/a/a-2');
       assert.equal(this.$link3.getAttribute('href'), '/a/a-3');
@@ -214,9 +205,9 @@ moduleFor(
       this.expectedModelHookParams = { id: 'a-2', q: 'lol', z: 0 };
       await this.transitionTo('article', 'a-2', { queryParams: { q: 'lol' } });
 
-      assert.deepEqual(this.controller.get('model'), { id: 'a-2' });
-      assert.equal(this.controller.get('q'), 'lol');
-      assert.equal(this.controller.get('z'), 0);
+      assert.deepEqual(this.controller.model, { id: 'a-2' });
+      assert.equal(this.controller.q, 'lol');
+      assert.equal(this.controller.z, 0);
       assert.equal(this.$link1.getAttribute('href'), '/a/a-1');
       assert.equal(this.$link2.getAttribute('href'), '/a/a-2?q=lol');
       assert.equal(this.$link3.getAttribute('href'), '/a/a-3');
@@ -224,9 +215,9 @@ moduleFor(
       this.expectedModelHookParams = { id: 'a-3', q: 'hay', z: 0 };
       await this.transitionTo('article', 'a-3', { queryParams: { q: 'hay' } });
 
-      assert.deepEqual(this.controller.get('model'), { id: 'a-3' });
-      assert.equal(this.controller.get('q'), 'hay');
-      assert.equal(this.controller.get('z'), 0);
+      assert.deepEqual(this.controller.model, { id: 'a-3' });
+      assert.equal(this.controller.q, 'hay');
+      assert.equal(this.controller.z, 0);
       assert.equal(this.$link1.getAttribute('href'), '/a/a-1');
       assert.equal(this.$link2.getAttribute('href'), '/a/a-2?q=lol');
       assert.equal(this.$link3.getAttribute('href'), '/a/a-3?q=hay');
@@ -234,9 +225,9 @@ moduleFor(
       this.expectedModelHookParams = { id: 'a-2', q: 'lol', z: 1 };
       await this.transitionTo('article', 'a-2', { queryParams: { z: 1 } });
 
-      assert.deepEqual(this.controller.get('model'), { id: 'a-2' });
-      assert.equal(this.controller.get('q'), 'lol');
-      assert.equal(this.controller.get('z'), 1);
+      assert.deepEqual(this.controller.model, { id: 'a-2' });
+      assert.equal(this.controller.q, 'lol');
+      assert.equal(this.controller.z, 1);
       assert.equal(this.$link1.getAttribute('href'), '/a/a-1');
       assert.equal(this.$link2.getAttribute('href'), '/a/a-2?q=lol&z=1');
       assert.equal(this.$link3.getAttribute('href'), '/a/a-3?q=hay');
@@ -249,9 +240,13 @@ moduleFor(
 
       this.setupApplication();
 
-      this.reopenController('article', {
-        queryParams: { q: { scope: 'controller' } },
-      });
+      this.subclass(
+        'controller:article',
+        (ArticleController) =>
+          class extends ArticleController {
+            queryParams = ['q', 'z', { q: { scope: 'controller' } }];
+          }
+      );
 
       await this.visitApplication();
       this.$link1.click();
@@ -268,9 +263,9 @@ moduleFor(
       this.$link2.click();
       await runLoopSettled();
 
-      assert.equal(this.controller.get('q'), 'lol');
-      assert.equal(this.controller.get('z'), 0);
-      assert.deepEqual(this.controller.get('model'), { id: 'a-2' });
+      assert.equal(this.controller.q, 'lol');
+      assert.equal(this.controller.z, 0);
+      assert.deepEqual(this.controller.model, { id: 'a-2' });
 
       assert.equal(this.$link1.getAttribute('href'), '/a/a-1?q=lol');
       assert.equal(this.$link2.getAttribute('href'), '/a/a-2?q=lol');
@@ -279,9 +274,9 @@ moduleFor(
       this.expectedModelHookParams = { id: 'a-3', q: 'haha', z: 123 };
       await this.transitionTo('/a/a-3?q=haha&z=123');
 
-      assert.deepEqual(this.controller.get('model'), { id: 'a-3' });
-      assert.equal(this.controller.get('q'), 'haha');
-      assert.equal(this.controller.get('z'), 123);
+      assert.deepEqual(this.controller.model, { id: 'a-3' });
+      assert.equal(this.controller.q, 'haha');
+      assert.equal(this.controller.z, 123);
 
       assert.equal(this.$link1.getAttribute('href'), '/a/a-1?q=haha');
       assert.equal(this.$link2.getAttribute('href'), '/a/a-2?q=haha');
@@ -303,7 +298,7 @@ moduleFor(
       await this.transitionTo('comments', 'a-1');
 
       let commentsCtrl = this.getController('comments');
-      assert.equal(commentsCtrl.get('page'), 1);
+      assert.equal(commentsCtrl.page, 1);
       this.assertCurrentPath('/a/a-1/comments');
 
       await this.setAndFlush(commentsCtrl, 'page', 2);
@@ -313,11 +308,11 @@ moduleFor(
       this.assertCurrentPath('/a/a-1/comments?page=3');
 
       await this.transitionTo('comments', 'a-2');
-      assert.equal(commentsCtrl.get('page'), 1);
+      assert.equal(commentsCtrl.page, 1);
       this.assertCurrentPath('/a/a-2/comments');
 
       await this.transitionTo('comments', 'a-1');
-      assert.equal(commentsCtrl.get('page'), 3);
+      assert.equal(commentsCtrl.page, 3);
       this.assertCurrentPath('/a/a-1/comments?page=3');
     }
 
@@ -328,14 +323,18 @@ moduleFor(
 
       this.setupApplication();
 
-      this.reopenRoute('article', {
-        resetController(controller, isExiting) {
-          this.controllerFor('comments').set('page', 1);
-          if (isExiting) {
-            controller.set('q', 'imdone');
+      this.subclass(
+        'route:article',
+        (ArticleRoute) =>
+          class extends ArticleRoute {
+            resetController(controller, isExiting) {
+              set(this.controllerFor('comments'), 'page', 1);
+              if (isExiting) {
+                set(controller, 'q', 'imdone');
+              }
+            }
           }
-        },
-      });
+      );
 
       this.add(
         'template:about',
@@ -351,19 +350,19 @@ moduleFor(
       await this.transitionTo('comments', 'a-1');
 
       let commentsCtrl = this.getController('comments');
-      assert.equal(commentsCtrl.get('page'), 1);
+      assert.equal(commentsCtrl.page, 1);
       this.assertCurrentPath('/a/a-1/comments');
 
       await this.setAndFlush(commentsCtrl, 'page', 2);
       this.assertCurrentPath('/a/a-1/comments?page=2');
 
       await this.transitionTo('comments', 'a-2');
-      assert.equal(commentsCtrl.get('page'), 1);
-      assert.equal(this.controller.get('q'), 'wat');
+      assert.equal(commentsCtrl.page, 1);
+      assert.equal(this.controller.q, 'wat');
 
       await this.transitionTo('comments', 'a-1');
       this.assertCurrentPath('/a/a-1/comments');
-      assert.equal(commentsCtrl.get('page'), 1);
+      assert.equal(commentsCtrl.page, 1);
 
       await this.transitionTo('about');
       assert.equal(document.getElementById('one').getAttribute('href'), '/a/a-1/comments?q=imdone');
@@ -415,19 +414,22 @@ moduleFor(
 
       this.add(
         'controller:site.article',
-        Controller.extend({
-          queryParams: ['q', 'z'],
-          q: 'wat',
-          z: 0,
-        })
+        class extends Controller {
+          queryParams = ['q', 'z'];
+
+          q = 'wat';
+
+          z = 0;
+        }
       );
 
       this.add(
         'controller:site.article.comments',
-        Controller.extend({
-          queryParams: 'page',
-          page: 1,
-        })
+        class extends Controller {
+          queryParams = ['page'];
+
+          page = 1;
+        }
       );
 
       this.add(
@@ -479,9 +481,9 @@ moduleFor(
       this.$link2.click();
       await runLoopSettled();
 
-      assert.equal(this.controller.get('q'), 'wat');
-      assert.equal(this.controller.get('z'), 0);
-      assert.deepEqual(this.controller.get('model'), { id: 'a-2' });
+      assert.equal(this.controller.q, 'wat');
+      assert.equal(this.controller.z, 0);
+      assert.deepEqual(this.controller.model, { id: 'a-2' });
       assert.equal(this.$link1.getAttribute('href'), '/site/a/a-1?q=lol');
       assert.equal(this.$link2.getAttribute('href'), '/site/a/a-2');
       assert.equal(this.$link3.getAttribute('href'), '/site/a/a-3');
@@ -497,9 +499,9 @@ moduleFor(
 
       await this.transitionTo('/site/a/a-1?q=lol');
 
-      assert.deepEqual(this.controller.get('model'), { id: 'a-1' });
-      assert.equal(this.controller.get('q'), 'lol');
-      assert.equal(this.controller.get('z'), 0);
+      assert.deepEqual(this.controller.model, { id: 'a-1' });
+      assert.equal(this.controller.q, 'lol');
+      assert.equal(this.controller.z, 0);
       assert.equal(this.$link1.getAttribute('href'), '/site/a/a-1?q=lol');
       assert.equal(this.$link2.getAttribute('href'), '/site/a/a-2');
       assert.equal(this.$link3.getAttribute('href'), '/site/a/a-3');
@@ -508,13 +510,9 @@ moduleFor(
 
       await this.transitionTo('/site/a/a-2?q=lol');
 
-      assert.deepEqual(
-        this.controller.get('model'),
-        { id: 'a-2' },
-        "controller's model changed to a-2"
-      );
-      assert.equal(this.controller.get('q'), 'lol');
-      assert.equal(this.controller.get('z'), 0);
+      assert.deepEqual(this.controller.model, { id: 'a-2' }, "controller's model changed to a-2");
+      assert.equal(this.controller.q, 'lol');
+      assert.equal(this.controller.z, 0);
       assert.equal(this.$link1.getAttribute('href'), '/site/a/a-1?q=lol');
       assert.equal(this.$link2.getAttribute('href'), '/site/a/a-2?q=lol');
       assert.equal(this.$link3.getAttribute('href'), '/site/a/a-3');
@@ -523,8 +521,8 @@ moduleFor(
 
       await this.transitionTo('/site/a/a-3?q=lol&z=123');
 
-      assert.equal(this.controller.get('q'), 'lol');
-      assert.equal(this.controller.get('z'), 123);
+      assert.equal(this.controller.q, 'lol');
+      assert.equal(this.controller.z, 123);
       assert.equal(this.$link1.getAttribute('href'), '/site/a/a-1?q=lol');
       assert.equal(this.$link2.getAttribute('href'), '/site/a/a-2?q=lol');
       assert.equal(this.$link3.getAttribute('href'), '/site/a/a-3?q=lol&z=123');
@@ -550,9 +548,9 @@ moduleFor(
       this.expectedModelHookParams = { id: 'a-1', q: 'wat', z: 0 };
       await this.transitionTo('site.article', 'a-1');
 
-      assert.deepEqual(this.controller.get('model'), { id: 'a-1' });
-      assert.equal(this.controller.get('q'), 'wat');
-      assert.equal(this.controller.get('z'), 0);
+      assert.deepEqual(this.controller.model, { id: 'a-1' });
+      assert.equal(this.controller.q, 'wat');
+      assert.equal(this.controller.z, 0);
       assert.equal(this.$link1.getAttribute('href'), '/site/a/a-1');
       assert.equal(this.$link2.getAttribute('href'), '/site/a/a-2');
       assert.equal(this.$link3.getAttribute('href'), '/site/a/a-3');
@@ -560,9 +558,9 @@ moduleFor(
       this.expectedModelHookParams = { id: 'a-2', q: 'lol', z: 0 };
       await this.transitionTo('site.article', 'a-2', { queryParams: { q: 'lol' } });
 
-      assert.deepEqual(this.controller.get('model'), { id: 'a-2' });
-      assert.equal(this.controller.get('q'), 'lol');
-      assert.equal(this.controller.get('z'), 0);
+      assert.deepEqual(this.controller.model, { id: 'a-2' });
+      assert.equal(this.controller.q, 'lol');
+      assert.equal(this.controller.z, 0);
       assert.equal(this.$link1.getAttribute('href'), '/site/a/a-1');
       assert.equal(this.$link2.getAttribute('href'), '/site/a/a-2?q=lol');
       assert.equal(this.$link3.getAttribute('href'), '/site/a/a-3');
@@ -570,9 +568,9 @@ moduleFor(
       this.expectedModelHookParams = { id: 'a-3', q: 'hay', z: 0 };
       await this.transitionTo('site.article', 'a-3', { queryParams: { q: 'hay' } });
 
-      assert.deepEqual(this.controller.get('model'), { id: 'a-3' });
-      assert.equal(this.controller.get('q'), 'hay');
-      assert.equal(this.controller.get('z'), 0);
+      assert.deepEqual(this.controller.model, { id: 'a-3' });
+      assert.equal(this.controller.q, 'hay');
+      assert.equal(this.controller.z, 0);
       assert.equal(this.$link1.getAttribute('href'), '/site/a/a-1');
       assert.equal(this.$link2.getAttribute('href'), '/site/a/a-2?q=lol');
       assert.equal(this.$link3.getAttribute('href'), '/site/a/a-3?q=hay');
@@ -580,9 +578,9 @@ moduleFor(
       this.expectedModelHookParams = { id: 'a-2', q: 'lol', z: 1 };
       await this.transitionTo('site.article', 'a-2', { queryParams: { z: 1 } });
 
-      assert.deepEqual(this.controller.get('model'), { id: 'a-2' });
-      assert.equal(this.controller.get('q'), 'lol');
-      assert.equal(this.controller.get('z'), 1);
+      assert.deepEqual(this.controller.model, { id: 'a-2' });
+      assert.equal(this.controller.q, 'lol');
+      assert.equal(this.controller.z, 1);
       assert.equal(this.$link1.getAttribute('href'), '/site/a/a-1');
       assert.equal(this.$link2.getAttribute('href'), '/site/a/a-2?q=lol&z=1');
       assert.equal(this.$link3.getAttribute('href'), '/site/a/a-3?q=hay');
@@ -595,9 +593,13 @@ moduleFor(
 
       this.setupApplication();
 
-      this.reopenController('site.article', {
-        queryParams: { q: { scope: 'controller' } },
-      });
+      this.subclass(
+        'controller:site.article',
+        (ArticleController) =>
+          class extends ArticleController {
+            queryParams = ['q', 'z', { q: { scope: 'controller' } }];
+          }
+      );
 
       await this.visitApplication();
       this.$link1.click();
@@ -614,9 +616,9 @@ moduleFor(
       this.$link2.click();
       await runLoopSettled();
 
-      assert.equal(this.controller.get('q'), 'lol');
-      assert.equal(this.controller.get('z'), 0);
-      assert.deepEqual(this.controller.get('model'), { id: 'a-2' });
+      assert.equal(this.controller.q, 'lol');
+      assert.equal(this.controller.z, 0);
+      assert.deepEqual(this.controller.model, { id: 'a-2' });
 
       assert.equal(this.$link1.getAttribute('href'), '/site/a/a-1?q=lol');
       assert.equal(this.$link2.getAttribute('href'), '/site/a/a-2?q=lol');
@@ -625,9 +627,9 @@ moduleFor(
       this.expectedModelHookParams = { id: 'a-3', q: 'haha', z: 123 };
       await this.transitionTo('/site/a/a-3?q=haha&z=123');
 
-      assert.deepEqual(this.controller.get('model'), { id: 'a-3' });
-      assert.equal(this.controller.get('q'), 'haha');
-      assert.equal(this.controller.get('z'), 123);
+      assert.deepEqual(this.controller.model, { id: 'a-3' });
+      assert.equal(this.controller.q, 'haha');
+      assert.equal(this.controller.z, 123);
 
       assert.equal(this.$link1.getAttribute('href'), '/site/a/a-1?q=haha');
       assert.equal(this.$link2.getAttribute('href'), '/site/a/a-2?q=haha');
@@ -649,7 +651,7 @@ moduleFor(
       await this.transitionTo('site.article.comments', 'a-1');
 
       let commentsCtrl = this.getController('site.article.comments');
-      assert.equal(commentsCtrl.get('page'), 1);
+      assert.equal(commentsCtrl.page, 1);
       this.assertCurrentPath('/site/a/a-1/comments');
 
       await this.setAndFlush(commentsCtrl, 'page', 2);
@@ -659,11 +661,11 @@ moduleFor(
       this.assertCurrentPath('/site/a/a-1/comments?page=3');
 
       await this.transitionTo('site.article.comments', 'a-2');
-      assert.equal(commentsCtrl.get('page'), 1);
+      assert.equal(commentsCtrl.page, 1);
       this.assertCurrentPath('/site/a/a-2/comments');
 
       await this.transitionTo('site.article.comments', 'a-1');
-      assert.equal(commentsCtrl.get('page'), 3);
+      assert.equal(commentsCtrl.page, 3);
       this.assertCurrentPath('/site/a/a-1/comments?page=3');
     }
 
@@ -674,14 +676,18 @@ moduleFor(
 
       this.setupApplication();
 
-      this.reopenRoute('site.article', {
-        resetController(controller, isExiting) {
-          this.controllerFor('site.article.comments').set('page', 1);
-          if (isExiting) {
-            controller.set('q', 'imdone');
+      this.subclass(
+        'route:site.article',
+        (ArticleRoute) =>
+          class extends ArticleRoute {
+            resetController(controller, isExiting) {
+              set(this.controllerFor('site.article.comments'), 'page', 1);
+              if (isExiting) {
+                set(controller, 'q', 'imdone');
+              }
+            }
           }
-        },
-      });
+      );
 
       this.add(
         'template:about',
@@ -697,19 +703,19 @@ moduleFor(
       await this.transitionTo('site.article.comments', 'a-1');
 
       let commentsCtrl = this.getController('site.article.comments');
-      assert.equal(commentsCtrl.get('page'), 1);
+      assert.equal(commentsCtrl.page, 1);
       this.assertCurrentPath('/site/a/a-1/comments');
 
       await this.setAndFlush(commentsCtrl, 'page', 2);
       this.assertCurrentPath('/site/a/a-1/comments?page=2');
 
       await this.transitionTo('site.article.comments', 'a-2');
-      assert.equal(commentsCtrl.get('page'), 1);
-      assert.equal(this.controller.get('q'), 'wat');
+      assert.equal(commentsCtrl.page, 1);
+      assert.equal(this.controller.q, 'wat');
 
       await this.transitionTo('site.article.comments', 'a-1');
       this.assertCurrentPath('/site/a/a-1/comments');
-      assert.equal(commentsCtrl.get('page'), 1);
+      assert.equal(commentsCtrl.page, 1);
 
       await this.transitionTo('about');
       assert.equal(
@@ -741,7 +747,7 @@ moduleFor(
         class extends Controller {
           siteArticles = site_articles;
           sites = sites;
-          @computed
+
           get allSitesAllArticles() {
             let ret = [];
             let siteArticles = this.siteArticles;
@@ -800,27 +806,31 @@ moduleFor(
 
       this.add(
         'controller:site',
-        Controller.extend({
-          queryParams: ['country'],
-          country: 'au',
-        })
+        class extends Controller {
+          queryParams = ['country'];
+
+          country = 'au';
+        }
       );
 
       this.add(
         'controller:site.article',
-        Controller.extend({
-          queryParams: ['q', 'z'],
-          q: 'wat',
-          z: 0,
-        })
+        class extends Controller {
+          queryParams = ['q', 'z'];
+
+          q = 'wat';
+
+          z = 0;
+        }
       );
 
       this.add(
         'controller:site.article.comments',
-        Controller.extend({
-          queryParams: ['page'],
-          page: 1,
-        })
+        class extends Controller {
+          queryParams = ['page'];
+
+          page = 1;
+        }
       );
 
       this.add(
@@ -874,8 +884,8 @@ moduleFor(
       await this.boot();
       this.links['s-1-a-1'].click();
       await runLoopSettled();
-      assert.deepEqual(this.site_controller.get('model'), { id: 's-1' });
-      assert.deepEqual(this.article_controller.get('model'), { id: 'a-1' });
+      assert.deepEqual(this.site_controller.model, { id: 's-1' });
+      assert.deepEqual(this.article_controller.model, { id: 'a-1' });
       this.assertCurrentPath('/site/s-1/a/a-1');
 
       await this.setAndFlush(this.article_controller, 'q', 'lol');
@@ -905,11 +915,11 @@ moduleFor(
       this.links['s-1-a-2'].click();
       await runLoopSettled();
 
-      assert.equal(this.site_controller.get('country'), 'us');
-      assert.equal(this.article_controller.get('q'), 'wat');
-      assert.equal(this.article_controller.get('z'), 0);
-      assert.deepEqual(this.site_controller.get('model'), { id: 's-1' });
-      assert.deepEqual(this.article_controller.get('model'), { id: 'a-2' });
+      assert.equal(this.site_controller.country, 'us');
+      assert.equal(this.article_controller.q, 'wat');
+      assert.equal(this.article_controller.z, 0);
+      assert.deepEqual(this.site_controller.model, { id: 's-1' });
+      assert.deepEqual(this.article_controller.model, { id: 'a-2' });
       assert.equal(this.links['s-1-a-1'].getAttribute('href'), '/site/s-1/a/a-1?country=us&q=lol');
       assert.equal(this.links['s-1-a-2'].getAttribute('href'), '/site/s-1/a/a-2?country=us');
       assert.equal(this.links['s-1-a-3'].getAttribute('href'), '/site/s-1/a/a-3?country=us');
@@ -923,11 +933,11 @@ moduleFor(
       this.links['s-2-a-2'].click();
       await runLoopSettled();
 
-      assert.equal(this.site_controller.get('country'), 'au');
-      assert.equal(this.article_controller.get('q'), 'wat');
-      assert.equal(this.article_controller.get('z'), 0);
-      assert.deepEqual(this.site_controller.get('model'), { id: 's-2' });
-      assert.deepEqual(this.article_controller.get('model'), { id: 'a-2' });
+      assert.equal(this.site_controller.country, 'au');
+      assert.equal(this.article_controller.q, 'wat');
+      assert.equal(this.article_controller.z, 0);
+      assert.deepEqual(this.site_controller.model, { id: 's-2' });
+      assert.deepEqual(this.article_controller.model, { id: 'a-2' });
       assert.equal(this.links['s-1-a-1'].getAttribute('href'), '/site/s-1/a/a-1?country=us&q=lol');
       assert.equal(this.links['s-1-a-2'].getAttribute('href'), '/site/s-1/a/a-2?country=us');
       assert.equal(this.links['s-1-a-3'].getAttribute('href'), '/site/s-1/a/a-3?country=us');
@@ -951,19 +961,15 @@ moduleFor(
       };
       await this.transitionTo('/site/s-1/a/a-1?q=lol');
 
+      assert.deepEqual(this.site_controller.model, { id: 's-1' }, "site controller's model is s-1");
       assert.deepEqual(
-        this.site_controller.get('model'),
-        { id: 's-1' },
-        "site controller's model is s-1"
-      );
-      assert.deepEqual(
-        this.article_controller.get('model'),
+        this.article_controller.model,
         { id: 'a-1' },
         "article controller's model is a-1"
       );
-      assert.equal(this.site_controller.get('country'), 'au');
-      assert.equal(this.article_controller.get('q'), 'lol');
-      assert.equal(this.article_controller.get('z'), 0);
+      assert.equal(this.site_controller.country, 'au');
+      assert.equal(this.article_controller.q, 'lol');
+      assert.equal(this.article_controller.z, 0);
       assert.equal(this.links['s-1-a-1'].getAttribute('href'), '/site/s-1/a/a-1?q=lol');
       assert.equal(this.links['s-1-a-2'].getAttribute('href'), '/site/s-1/a/a-2');
       assert.equal(this.links['s-1-a-3'].getAttribute('href'), '/site/s-1/a/a-3');
@@ -982,19 +988,15 @@ moduleFor(
       };
       await this.transitionTo('/site/s-2/a/a-1?country=us&q=lol');
 
+      assert.deepEqual(this.site_controller.model, { id: 's-2' }, "site controller's model is s-2");
       assert.deepEqual(
-        this.site_controller.get('model'),
-        { id: 's-2' },
-        "site controller's model is s-2"
-      );
-      assert.deepEqual(
-        this.article_controller.get('model'),
+        this.article_controller.model,
         { id: 'a-1' },
         "article controller's model is a-1"
       );
-      assert.equal(this.site_controller.get('country'), 'us');
-      assert.equal(this.article_controller.get('q'), 'lol');
-      assert.equal(this.article_controller.get('z'), 0);
+      assert.equal(this.site_controller.country, 'us');
+      assert.equal(this.article_controller.q, 'lol');
+      assert.equal(this.article_controller.z, 0);
       assert.equal(this.links['s-1-a-1'].getAttribute('href'), '/site/s-1/a/a-1?q=lol');
       assert.equal(this.links['s-1-a-2'].getAttribute('href'), '/site/s-1/a/a-2');
       assert.equal(this.links['s-1-a-3'].getAttribute('href'), '/site/s-1/a/a-3');
@@ -1013,19 +1015,15 @@ moduleFor(
       };
       await this.transitionTo('/site/s-2/a/a-2?country=us&q=lol');
 
+      assert.deepEqual(this.site_controller.model, { id: 's-2' }, "site controller's model is s-2");
       assert.deepEqual(
-        this.site_controller.get('model'),
-        { id: 's-2' },
-        "site controller's model is s-2"
-      );
-      assert.deepEqual(
-        this.article_controller.get('model'),
+        this.article_controller.model,
         { id: 'a-2' },
         "article controller's model is a-2"
       );
-      assert.equal(this.site_controller.get('country'), 'us');
-      assert.equal(this.article_controller.get('q'), 'lol');
-      assert.equal(this.article_controller.get('z'), 0);
+      assert.equal(this.site_controller.country, 'us');
+      assert.equal(this.article_controller.q, 'lol');
+      assert.equal(this.article_controller.z, 0);
       assert.equal(this.links['s-1-a-1'].getAttribute('href'), '/site/s-1/a/a-1?q=lol');
       assert.equal(this.links['s-1-a-2'].getAttribute('href'), '/site/s-1/a/a-2?q=lol');
       assert.equal(this.links['s-1-a-3'].getAttribute('href'), '/site/s-1/a/a-3');
@@ -1044,19 +1042,15 @@ moduleFor(
       };
       await this.transitionTo('/site/s-2/a/a-3?country=us&q=lol&z=123');
 
+      assert.deepEqual(this.site_controller.model, { id: 's-2' }, "site controller's model is s-2");
       assert.deepEqual(
-        this.site_controller.get('model'),
-        { id: 's-2' },
-        "site controller's model is s-2"
-      );
-      assert.deepEqual(
-        this.article_controller.get('model'),
+        this.article_controller.model,
         { id: 'a-3' },
         "article controller's model is a-3"
       );
-      assert.equal(this.site_controller.get('country'), 'us');
-      assert.equal(this.article_controller.get('q'), 'lol');
-      assert.equal(this.article_controller.get('z'), 123);
+      assert.equal(this.site_controller.country, 'us');
+      assert.equal(this.article_controller.q, 'lol');
+      assert.equal(this.article_controller.z, 123);
       assert.equal(this.links['s-1-a-1'].getAttribute('href'), '/site/s-1/a/a-1?q=lol');
       assert.equal(this.links['s-1-a-2'].getAttribute('href'), '/site/s-1/a/a-2?q=lol');
       assert.equal(this.links['s-1-a-3'].getAttribute('href'), '/site/s-1/a/a-3?q=lol&z=123');
@@ -1078,19 +1072,15 @@ moduleFor(
       };
       await this.transitionTo('/site/s-3/a/a-3?country=nz&q=lol&z=123');
 
+      assert.deepEqual(this.site_controller.model, { id: 's-3' }, "site controller's model is s-3");
       assert.deepEqual(
-        this.site_controller.get('model'),
-        { id: 's-3' },
-        "site controller's model is s-3"
-      );
-      assert.deepEqual(
-        this.article_controller.get('model'),
+        this.article_controller.model,
         { id: 'a-3' },
         "article controller's model is a-3"
       );
-      assert.equal(this.site_controller.get('country'), 'nz');
-      assert.equal(this.article_controller.get('q'), 'lol');
-      assert.equal(this.article_controller.get('z'), 123);
+      assert.equal(this.site_controller.country, 'nz');
+      assert.equal(this.article_controller.q, 'lol');
+      assert.equal(this.article_controller.z, 123);
       assert.equal(this.links['s-1-a-1'].getAttribute('href'), '/site/s-1/a/a-1?q=lol');
       assert.equal(this.links['s-1-a-2'].getAttribute('href'), '/site/s-1/a/a-2?q=lol');
       assert.equal(this.links['s-1-a-3'].getAttribute('href'), '/site/s-1/a/a-3?q=lol&z=123');
@@ -1122,11 +1112,11 @@ moduleFor(
       };
       await this.transitionTo('site.article', 's-1', 'a-1');
 
-      assert.deepEqual(this.site_controller.get('model'), { id: 's-1' });
-      assert.deepEqual(this.article_controller.get('model'), { id: 'a-1' });
-      assert.equal(this.site_controller.get('country'), 'au');
-      assert.equal(this.article_controller.get('q'), 'wat');
-      assert.equal(this.article_controller.get('z'), 0);
+      assert.deepEqual(this.site_controller.model, { id: 's-1' });
+      assert.deepEqual(this.article_controller.model, { id: 'a-1' });
+      assert.equal(this.site_controller.country, 'au');
+      assert.equal(this.article_controller.q, 'wat');
+      assert.equal(this.article_controller.z, 0);
       assert.equal(this.links['s-1-a-1'].getAttribute('href'), '/site/s-1/a/a-1');
       assert.equal(this.links['s-1-a-2'].getAttribute('href'), '/site/s-1/a/a-2');
       assert.equal(this.links['s-1-a-3'].getAttribute('href'), '/site/s-1/a/a-3');
@@ -1147,11 +1137,11 @@ moduleFor(
         queryParams: { q: 'lol' },
       });
 
-      assert.deepEqual(this.site_controller.get('model'), { id: 's-1' });
-      assert.deepEqual(this.article_controller.get('model'), { id: 'a-2' });
-      assert.equal(this.site_controller.get('country'), 'au');
-      assert.equal(this.article_controller.get('q'), 'lol');
-      assert.equal(this.article_controller.get('z'), 0);
+      assert.deepEqual(this.site_controller.model, { id: 's-1' });
+      assert.deepEqual(this.article_controller.model, { id: 'a-2' });
+      assert.equal(this.site_controller.country, 'au');
+      assert.equal(this.article_controller.q, 'lol');
+      assert.equal(this.article_controller.z, 0);
       assert.equal(this.links['s-1-a-1'].getAttribute('href'), '/site/s-1/a/a-1');
       assert.equal(this.links['s-1-a-2'].getAttribute('href'), '/site/s-1/a/a-2?q=lol');
       assert.equal(this.links['s-1-a-3'].getAttribute('href'), '/site/s-1/a/a-3');
@@ -1172,11 +1162,11 @@ moduleFor(
         queryParams: { q: 'hay' },
       });
 
-      assert.deepEqual(this.site_controller.get('model'), { id: 's-1' });
-      assert.deepEqual(this.article_controller.get('model'), { id: 'a-3' });
-      assert.equal(this.site_controller.get('country'), 'au');
-      assert.equal(this.article_controller.get('q'), 'hay');
-      assert.equal(this.article_controller.get('z'), 0);
+      assert.deepEqual(this.site_controller.model, { id: 's-1' });
+      assert.deepEqual(this.article_controller.model, { id: 'a-3' });
+      assert.equal(this.site_controller.country, 'au');
+      assert.equal(this.article_controller.q, 'hay');
+      assert.equal(this.article_controller.z, 0);
       assert.equal(this.links['s-1-a-1'].getAttribute('href'), '/site/s-1/a/a-1');
       assert.equal(this.links['s-1-a-2'].getAttribute('href'), '/site/s-1/a/a-2?q=lol');
       assert.equal(this.links['s-1-a-3'].getAttribute('href'), '/site/s-1/a/a-3?q=hay');
@@ -1197,11 +1187,11 @@ moduleFor(
         queryParams: { z: 1 },
       });
 
-      assert.deepEqual(this.site_controller.get('model'), { id: 's-1' });
-      assert.deepEqual(this.article_controller.get('model'), { id: 'a-2' });
-      assert.equal(this.site_controller.get('country'), 'au');
-      assert.equal(this.article_controller.get('q'), 'lol');
-      assert.equal(this.article_controller.get('z'), 1);
+      assert.deepEqual(this.site_controller.model, { id: 's-1' });
+      assert.deepEqual(this.article_controller.model, { id: 'a-2' });
+      assert.equal(this.site_controller.country, 'au');
+      assert.equal(this.article_controller.q, 'lol');
+      assert.equal(this.article_controller.z, 1);
       assert.equal(this.links['s-1-a-1'].getAttribute('href'), '/site/s-1/a/a-1');
       assert.equal(this.links['s-1-a-2'].getAttribute('href'), '/site/s-1/a/a-2?q=lol&z=1');
       assert.equal(this.links['s-1-a-3'].getAttribute('href'), '/site/s-1/a/a-3?q=hay');
@@ -1222,11 +1212,11 @@ moduleFor(
         queryParams: { country: 'us' },
       });
 
-      assert.deepEqual(this.site_controller.get('model'), { id: 's-2' });
-      assert.deepEqual(this.article_controller.get('model'), { id: 'a-2' });
-      assert.equal(this.site_controller.get('country'), 'us');
-      assert.equal(this.article_controller.get('q'), 'lol');
-      assert.equal(this.article_controller.get('z'), 1);
+      assert.deepEqual(this.site_controller.model, { id: 's-2' });
+      assert.deepEqual(this.article_controller.model, { id: 'a-2' });
+      assert.equal(this.site_controller.country, 'us');
+      assert.equal(this.article_controller.q, 'lol');
+      assert.equal(this.article_controller.z, 1);
       assert.equal(this.links['s-1-a-1'].getAttribute('href'), '/site/s-1/a/a-1');
       assert.equal(this.links['s-1-a-2'].getAttribute('href'), '/site/s-1/a/a-2?q=lol&z=1');
       assert.equal(this.links['s-1-a-3'].getAttribute('href'), '/site/s-1/a/a-3?q=hay');
@@ -1250,11 +1240,11 @@ moduleFor(
         queryParams: { q: 'yeah' },
       });
 
-      assert.deepEqual(this.site_controller.get('model'), { id: 's-2' });
-      assert.deepEqual(this.article_controller.get('model'), { id: 'a-1' });
-      assert.equal(this.site_controller.get('country'), 'us');
-      assert.equal(this.article_controller.get('q'), 'yeah');
-      assert.equal(this.article_controller.get('z'), 0);
+      assert.deepEqual(this.site_controller.model, { id: 's-2' });
+      assert.deepEqual(this.article_controller.model, { id: 'a-1' });
+      assert.equal(this.site_controller.country, 'us');
+      assert.equal(this.article_controller.q, 'yeah');
+      assert.equal(this.article_controller.z, 0);
       assert.equal(this.links['s-1-a-1'].getAttribute('href'), '/site/s-1/a/a-1?q=yeah');
       assert.equal(this.links['s-1-a-2'].getAttribute('href'), '/site/s-1/a/a-2?q=lol&z=1');
       assert.equal(this.links['s-1-a-3'].getAttribute('href'), '/site/s-1/a/a-3?q=hay');
@@ -1278,11 +1268,11 @@ moduleFor(
         queryParams: { country: 'nz', z: 3 },
       });
 
-      assert.deepEqual(this.site_controller.get('model'), { id: 's-3' });
-      assert.deepEqual(this.article_controller.get('model'), { id: 'a-3' });
-      assert.equal(this.site_controller.get('country'), 'nz');
-      assert.equal(this.article_controller.get('q'), 'hay');
-      assert.equal(this.article_controller.get('z'), 3);
+      assert.deepEqual(this.site_controller.model, { id: 's-3' });
+      assert.deepEqual(this.article_controller.model, { id: 'a-3' });
+      assert.equal(this.site_controller.country, 'nz');
+      assert.equal(this.article_controller.q, 'hay');
+      assert.equal(this.article_controller.z, 3);
       assert.equal(this.links['s-1-a-1'].getAttribute('href'), '/site/s-1/a/a-1?q=yeah');
       assert.equal(this.links['s-1-a-2'].getAttribute('href'), '/site/s-1/a/a-2?q=lol&z=1');
       assert.equal(this.links['s-1-a-3'].getAttribute('href'), '/site/s-1/a/a-3?q=hay&z=3');
diff --git a/packages/ember/tests/routing/query_params_test/overlapping_query_params_test.js b/packages/ember/tests/routing/query_params_test/overlapping_query_params_test.js
index 3843cde3489..3ac00725bbd 100644
--- a/packages/ember/tests/routing/query_params_test/overlapping_query_params_test.js
+++ b/packages/ember/tests/routing/query_params_test/overlapping_query_params_test.js
@@ -1,4 +1,5 @@
 import Controller from '@ember/controller';
+import { set } from '@ember/object';
 import Route from '@ember/routing/route';
 import { QueryParamTestCase, moduleFor, runLoopSettled } from 'internal-test-helpers';
 
@@ -37,14 +38,14 @@ moduleFor(
       await this.setAndFlush(parentChildController, 'page', 1);
       this.assertCurrentPath('/parent/child');
 
-      parentController.set('page', 2);
-      parentChildController.set('page', 2);
+      set(parentController, 'page', 2);
+      set(parentChildController, 'page', 2);
       await runLoopSettled();
 
       this.assertCurrentPath('/parent/child?childPage=2&parentPage=2');
 
-      parentController.set('page', 1);
-      parentChildController.set('page', 1);
+      set(parentController, 'page', 1);
+      set(parentChildController, 'page', 1);
       await runLoopSettled();
 
       this.assertCurrentPath('/parent/child');
@@ -115,9 +116,9 @@ moduleFor(
     ) {
       assert.expect(1);
 
-      let parentController = Controller.extend({
-        queryParams: { page: 'page' },
-      });
+      let parentController = class extends Controller {
+        queryParams = [{ page: 'page' }];
+      };
       this.add('controller:parent', parentController);
       this.add(
         'route:parent.child',
@@ -149,19 +150,21 @@ moduleFor(
     async ['@test Support shared but overridable query param defaults'](assert) {
       assert.expect(7);
 
-      let hasPage = {
-        queryParams: 'page',
-        page: 1,
-      };
-
       this.add(
         'controller:parent',
-        Controller.extend(hasPage, {
-          queryParams: { page: 'yespage' },
-        })
+        class extends Controller {
+          queryParams = ['page', { page: 'yespage' }];
+          page = 1;
+        }
       );
 
-      this.add('controller:parent.child', Controller.extend(hasPage));
+      this.add(
+        'controller:parent.child',
+        class extends Controller {
+          queryParams = ['page'];
+          page = 1;
+        }
+      );
 
       await this.setupBase();
       this.assertCurrentPath('/parent/child');
@@ -171,13 +174,13 @@ moduleFor(
 
       await this.setAndFlush(parentChildController, 'page', 2);
       this.assertCurrentPath('/parent/child?page=2');
-      assert.equal(parentController.get('page'), 1);
-      assert.equal(parentChildController.get('page'), 2);
+      assert.equal(parentController.page, 1);
+      assert.equal(parentChildController.page, 2);
 
       await this.setAndFlush(parentController, 'page', 2);
       this.assertCurrentPath('/parent/child?page=2&yespage=2');
-      assert.equal(parentController.get('page'), 2);
-      assert.equal(parentChildController.get('page'), 2);
+      assert.equal(parentController.page, 2);
+      assert.equal(parentChildController.page, 2);
     }
   }
 );
diff --git a/packages/ember/tests/routing/router_service_test/basic_test.js b/packages/ember/tests/routing/router_service_test/basic_test.js
index aa5cc812eea..a2f20bef83b 100644
--- a/packages/ember/tests/routing/router_service_test/basic_test.js
+++ b/packages/ember/tests/routing/router_service_test/basic_test.js
@@ -19,7 +19,7 @@ moduleFor(
         assert.deepEqual(queryParams, {});
         assert.deepEqual(paramNames, []);
 
-        assert.equal(this.routerService.get('currentRouteName'), 'parent.index');
+        assert.equal(this.routerService.currentRouteName, 'parent.index');
       });
     }
 
@@ -35,7 +35,7 @@ moduleFor(
         assert.deepEqual(queryParams, {});
         assert.deepEqual(paramNames, []);
 
-        assert.equal(this.routerService.get('currentRouteName'), 'parent.child');
+        assert.equal(this.routerService.currentRouteName, 'parent.child');
       });
     }
 
@@ -57,7 +57,7 @@ moduleFor(
           assert.equal(name, 'parent.sister');
           assert.equal(localName, 'sister');
 
-          assert.equal(this.routerService.get('currentRouteName'), 'parent.sister');
+          assert.equal(this.routerService.currentRouteName, 'parent.sister');
         });
     }
 
@@ -93,7 +93,7 @@ moduleFor(
           assert.equal(name, 'parent.child');
           assert.equal(localName, 'child');
 
-          assert.equal(this.routerService.get('currentRouteName'), 'parent.child');
+          assert.equal(this.routerService.currentRouteName, 'parent.child');
 
           return this.visit('/sister');
         })
@@ -103,7 +103,7 @@ moduleFor(
           assert.equal(name, 'parent.sister');
           assert.equal(localName, 'sister');
 
-          assert.equal(this.routerService.get('currentRouteName'), 'parent.sister');
+          assert.equal(this.routerService.currentRouteName, 'parent.sister');
 
           return this.visit('/brother');
         })
@@ -113,7 +113,7 @@ moduleFor(
           assert.equal(name, 'parent.brother');
           assert.equal(localName, 'brother');
 
-          assert.equal(this.routerService.get('currentRouteName'), 'parent.brother');
+          assert.equal(this.routerService.currentRouteName, 'parent.brother');
         });
     }
 
@@ -121,7 +121,7 @@ moduleFor(
       assert.expect(1);
 
       return this.visit('/').then(() => {
-        assert.equal(this.routerService.get('rootURL'), '/');
+        assert.equal(this.routerService.rootURL, '/');
       });
     }
 
@@ -139,7 +139,7 @@ moduleFor(
       );
 
       return this.visit('/').then(() => {
-        assert.equal(this.routerService.get('rootURL'), '/homepage');
+        assert.equal(this.routerService.rootURL, '/homepage');
       });
     }
 
@@ -147,7 +147,7 @@ moduleFor(
       assert.expect(2);
 
       return this.visit('/').then(() => {
-        let location = this.routerService.get('location');
+        let location = this.routerService.location;
         assert.ok(location);
         assert.ok(location instanceof NoneLocation);
       });
@@ -156,14 +156,19 @@ moduleFor(
     ['@test RouterService can be injected into router and accessed on init'](assert) {
       assert.expect(1);
 
-      this.router.reopen({
-        routerService: service('router'),
-        init() {
-          this.routerService.one('routeDidChange', () => {
-            assert.ok(true, 'routeDidChange event listener called');
-          });
-        },
-      });
+      this.subclass(
+        'router:main',
+        (Router) =>
+          class extends Router {
+            @service('router') routerService;
+
+            init() {
+              this.routerService.one('routeDidChange', () => {
+                assert.ok(true, 'routeDidChange event listener called');
+              });
+            }
+          }
+      );
 
       return this.visit('/');
     }
diff --git a/packages/ember/tests/routing/router_service_test/recognize_test.js b/packages/ember/tests/routing/router_service_test/recognize_test.js
index 19674c280dd..03884bcf61d 100644
--- a/packages/ember/tests/routing/router_service_test/recognize_test.js
+++ b/packages/ember/tests/routing/router_service_test/recognize_test.js
@@ -33,9 +33,13 @@ moduleFor(
     }
 
     '@test respects the usage of a different rootURL'(assert) {
-      this.router.reopen({
-        rootURL: '/app/',
-      });
+      this.subclass(
+        'router:main',
+        (Router) =>
+          class extends Router {
+            rootURL = '/app/';
+          }
+      );
 
       return this.visit('/app').then(() => {
         let routeInfo = this.routerService.recognize('/app/child/');
@@ -51,9 +55,13 @@ moduleFor(
       this.add('template:parent', precompileTemplate('Parent'));
       this.add('template:dynamic-with-child.child', precompileTemplate('Dynamic Child'));
 
-      this.router.reopen({
-        rootURL: '/app/',
-      });
+      this.subclass(
+        'router:main',
+        (Router) =>
+          class extends Router {
+            rootURL = '/app/';
+          }
+      );
 
       return this.visit('/app').then(() => {
         expectAssertion(() => {
@@ -138,9 +146,13 @@ moduleFor(
     }
 
     '@test respects the usage of a different rootURL'(assert) {
-      this.router.reopen({
-        rootURL: '/app/',
-      });
+      this.subclass(
+        'router:main',
+        (Router) =>
+          class extends Router {
+            rootURL = '/app/';
+          }
+      );
 
       return this.visit('/app')
         .then(() => {
@@ -156,9 +168,13 @@ moduleFor(
     }
 
     '@test must include rootURL'() {
-      this.router.reopen({
-        rootURL: '/app/',
-      });
+      this.subclass(
+        'router:main',
+        (Router) =>
+          class extends Router {
+            rootURL = '/app/';
+          }
+      );
 
       return this.visit('/app').then(() => {
         expectAssertion(() => {
diff --git a/packages/ember/tests/routing/router_service_test/transitionTo_test.js b/packages/ember/tests/routing/router_service_test/transitionTo_test.js
index 2378177d65d..af7776804ba 100644
--- a/packages/ember/tests/routing/router_service_test/transitionTo_test.js
+++ b/packages/ember/tests/routing/router_service_test/transitionTo_test.js
@@ -3,7 +3,7 @@ import Component from '@glimmer/component';
 import Route from '@ember/routing/route';
 import NoneLocation from '@ember/routing/none-location';
 import Controller from '@ember/controller';
-import { action, get } from '@ember/object';
+import { action, get, set } from '@ember/object';
 import { precompileTemplate } from '@ember/template-compilation';
 import { setComponentTemplate } from '@glimmer/manager';
 import { RouterTestCase, moduleFor } from 'internal-test-helpers';
@@ -24,12 +24,12 @@ moduleFor(
         class extends NoneLocation {
           setURL(path) {
             testCase.state.push(path);
-            this.set('path', path);
+            set(this, 'path', path);
           }
 
           replaceURL(path) {
             testCase.state.splice(testCase.state.length - 1, 1, path);
-            this.set('path', path);
+            set(this, 'path', path);
           }
         }
       );
@@ -127,7 +127,7 @@ moduleFor(
       componentInstance.transitionToSister();
       await settled();
 
-      assert.equal(this.routerService.get('currentRouteName'), 'parent.sister');
+      assert.equal(this.routerService.currentRouteName, 'parent.sister');
     }
 
     async ['@test RouterService#transitionTo with basic route using URL'](assert) {
@@ -161,7 +161,7 @@ moduleFor(
       componentInstance.transitionToSister();
       await settled();
 
-      assert.equal(this.routerService.get('currentRouteName'), 'parent.sister');
+      assert.equal(this.routerService.currentRouteName, 'parent.sister');
     }
 
     async ['@test RouterService#transitionTo with dynamic segment'](assert) {
@@ -197,8 +197,8 @@ moduleFor(
       componentInstance.transitionToDynamic();
       await settled();
 
-      assert.equal(this.routerService.get('currentRouteName'), 'dynamic');
-      assert.equal(this.routerService.get('currentURL'), '/dynamic/1');
+      assert.equal(this.routerService.currentRouteName, 'dynamic');
+      assert.equal(this.routerService.currentURL, '/dynamic/1');
       this.assertText('much dynamicism');
     }
 
@@ -244,8 +244,8 @@ moduleFor(
       componentInstance.transitionToDynamic();
       await settled();
 
-      assert.equal(this.routerService.get('currentRouteName'), 'dynamic');
-      assert.equal(this.routerService.get('currentURL'), '/dynamic/1');
+      assert.equal(this.routerService.currentRouteName, 'dynamic');
+      assert.equal(this.routerService.currentURL, '/dynamic/1');
       this.assertText('much dynamicism');
     }
 
@@ -256,10 +256,11 @@ moduleFor(
 
       this.add(
         'controller:parent.child',
-        Controller.extend({
-          queryParams: ['sort'],
-          sort: 'ASC',
-        })
+        class extends Controller {
+          queryParams = ['sort'];
+
+          sort = 'ASC';
+        }
       );
 
       let queryParams = this.buildQueryParams({ sort: 'ASC' });
@@ -269,7 +270,7 @@ moduleFor(
           return this.routerService.transitionTo('parent.child', queryParams);
         })
         .then(() => {
-          assert.equal(this.routerService.get('currentURL'), '/child');
+          assert.equal(this.routerService.currentURL, '/child');
         });
     }
 
@@ -278,9 +279,9 @@ moduleFor(
 
       this.add(
         'controller:parent.child',
-        Controller.extend({
-          queryParams: ['sort'],
-        })
+        class extends Controller {
+          queryParams = ['sort'];
+        }
       );
 
       let queryParams = this.buildQueryParams({ sort: 'DESC' });
@@ -290,13 +291,13 @@ moduleFor(
           return this.routerService.transitionTo('parent.child');
         })
         .then(() => {
-          assert.equal(this.routerService.get('currentURL'), '/child');
+          assert.equal(this.routerService.currentURL, '/child');
         })
         .then(() => {
           return this.routerService.transitionTo(queryParams);
         })
         .then(() => {
-          assert.equal(this.routerService.get('currentURL'), '/child?sort=DESC');
+          assert.equal(this.routerService.currentURL, '/child?sort=DESC');
         });
     }
 
@@ -305,12 +306,15 @@ moduleFor(
 
       this.add(
         'controller:parent.child',
-        Controller.extend({
-          queryParams: ['sort', 'page', 'category', 'extra'],
-          sort: 'ASC',
-          page: null,
-          category: undefined,
-        })
+        class extends Controller {
+          queryParams = ['sort', 'page', 'category', 'extra'];
+
+          sort = 'ASC';
+
+          page = null;
+
+          category = undefined;
+        }
       );
 
       let queryParams = this.buildQueryParams({ sort: 'DESC' });
@@ -320,7 +324,7 @@ moduleFor(
           return this.routerService.transitionTo('parent.child', queryParams);
         })
         .then(() => {
-          assert.equal(this.routerService.get('currentURL'), '/child?sort=DESC');
+          assert.equal(this.routerService.currentURL, '/child?sort=DESC');
         });
     }
 
@@ -331,12 +335,15 @@ moduleFor(
 
       this.add(
         'controller:parent.child',
-        Controller.extend({
-          queryParams: {
-            cont_sort: 'url_sort',
-          },
-          cont_sort: 'ASC',
-        })
+        class extends Controller {
+          queryParams = [
+            {
+              cont_sort: 'url_sort',
+            },
+          ];
+
+          cont_sort = 'ASC';
+        }
       );
 
       let queryParams = this.buildQueryParams({ url_sort: 'DESC' });
@@ -346,7 +353,7 @@ moduleFor(
           return this.routerService.transitionTo('parent.child', queryParams);
         })
         .then(() => {
-          assert.equal(this.routerService.get('currentURL'), '/child?url_sort=DESC');
+          assert.equal(this.routerService.currentURL, '/child?url_sort=DESC');
         });
     }
 
@@ -357,12 +364,15 @@ moduleFor(
 
       this.add(
         'controller:parent.child',
-        Controller.extend({
-          queryParams: {
-            cont_sort: 'url_sort',
-          },
-          cont_sort: 'ASC',
-        })
+        class extends Controller {
+          queryParams = [
+            {
+              cont_sort: 'url_sort',
+            },
+          ];
+
+          cont_sort = 'ASC';
+        }
       );
 
       let queryParams = this.buildQueryParams({ cont_sort: 'ASC' });
@@ -396,16 +406,17 @@ moduleFor(
 
       this.add(
         'route:parent.child',
-        Route.extend({
-          queryParams: {
+        class extends Route {
+          queryParams = {
             cont_sort: { as: 'url_sort' },
-          },
-          cont_sort: 'ASC',
-        })
+          };
+
+          cont_sort = 'ASC';
+        }
       );
 
       return this.visit('/').then(() => {
-        assert.equal(this.routerService.get('currentURL'), '/child?url_sort=ASC');
+        assert.equal(this.routerService.currentURL, '/child?url_sort=ASC');
       });
     }
 
@@ -426,13 +437,13 @@ moduleFor(
       );
       this.add(
         'controller:parent',
-        Controller.extend({
-          queryParams: ['url_sort'],
-        })
+        class extends Controller {
+          queryParams = ['url_sort'];
+        }
       );
 
       return this.visit('/child?url_sort=a').then(() => {
-        assert.equal(this.routerService.get('currentURL'), '/?url_sort=a');
+        assert.equal(this.routerService.currentURL, '/?url_sort=a');
       });
     }
 
@@ -459,22 +470,23 @@ moduleFor(
 
       this.add(
         'controller:parent.child',
-        Controller.extend({
-          queryParams: ['bar'],
-          bar: null,
-        })
+        class extends Controller {
+          queryParams = ['bar'];
+
+          bar = null;
+        }
       );
 
       await this.visit('/');
       await this.routerService.transitionTo('parent.child').followRedirects();
 
       assert.equal(
-        this.routerService.get('currentURL'),
+        this.routerService.currentURL,
         '/child?bar=1',
         'redirected to self with query param'
       );
 
-      assert.equal(this.routerService.get('currentRouteName'), 'parent.child');
+      assert.equal(this.routerService.currentRouteName, 'parent.child');
     }
 
     async ['@test Redirecting to same route with query params from beforeModel works via direct visit'](
@@ -500,21 +512,22 @@ moduleFor(
 
       this.add(
         'controller:parent.child',
-        Controller.extend({
-          queryParams: ['bar'],
-          bar: null,
-        })
+        class extends Controller {
+          queryParams = ['bar'];
+
+          bar = null;
+        }
       );
 
       await this.visit('/child');
 
       assert.equal(
-        this.routerService.get('currentURL'),
+        this.routerService.currentURL,
         '/child?bar=1',
         'redirected to self with query param'
       );
 
-      assert.equal(this.routerService.get('currentRouteName'), 'parent.child');
+      assert.equal(this.routerService.currentRouteName, 'parent.child');
     }
 
     async ['@test RouterService#transitionTo supports query params from a service during beforeModel'](
@@ -568,19 +581,15 @@ moduleFor(
 
       await this.visit('/child');
 
-      assert.equal(
-        this.routerService.get('currentRouteName'),
-        'parent',
-        'redirects to the target route'
-      );
+      assert.equal(this.routerService.currentRouteName, 'parent', 'redirects to the target route');
 
-      let currentURL = this.routerService.get('currentURL');
+      let currentURL = this.routerService.currentURL;
 
       assert.equal(currentURL, '/parent?foo=bar', 'uses the query param in the final URL');
 
       let controller = this.controllerFor('parent');
 
-      assert.equal(controller.get('foo'), 'bar', 'sets the controller query param');
+      assert.equal(controller.foo, 'bar', 'sets the controller query param');
     }
 
     async ['@test RouterService#transitionTo with route name and unchanged application query params does not abort or re-run application model hook'](
@@ -611,11 +620,13 @@ moduleFor(
 
       this.add(
         'controller:application',
-        Controller.extend({
-          queryParams: ['filter', 'sort'],
-          filter: '',
-          sort: '',
-        })
+        class extends Controller {
+          queryParams = ['filter', 'sort'];
+
+          filter = '';
+
+          sort = '';
+        }
       );
 
       await this.visit('/?filter=&sort=');
@@ -629,7 +640,7 @@ moduleFor(
       await this.routerService.transitionTo('parent.child');
 
       assert.equal(
-        this.routerService.get('currentRouteName'),
+        this.routerService.currentRouteName,
         'parent.child',
         'transitioned to child route'
       );
@@ -669,11 +680,13 @@ moduleFor(
 
       this.add(
         'controller:application',
-        Controller.extend({
-          queryParams: ['filter', 'sort'],
-          filter: '',
-          sort: '',
-        })
+        class extends Controller {
+          queryParams = ['filter', 'sort'];
+
+          filter = '';
+
+          sort = '';
+        }
       );
 
       await this.visit('/?filter=&sort=');
@@ -687,7 +700,7 @@ moduleFor(
       await this.routerService.transitionTo('/child?filter=&sort=');
 
       assert.equal(
-        this.routerService.get('currentRouteName'),
+        this.routerService.currentRouteName,
         'parent.child',
         'transitioned to child route'
       );
diff --git a/packages/internal-test-helpers/lib/test-cases/test-resolver-application.ts b/packages/internal-test-helpers/lib/test-cases/test-resolver-application.ts
index 199a996607c..13733e39be8 100644
--- a/packages/internal-test-helpers/lib/test-cases/test-resolver-application.ts
+++ b/packages/internal-test-helpers/lib/test-cases/test-resolver-application.ts
@@ -15,4 +15,17 @@ export default abstract class TestResolverApplicationTestCase extends AbstractAp
   add(specifier: string, factory: InternalFactory<object> | object) {
     this.resolver!.add(specifier, factory);
   }
+
+  /**
+    Replaces a registration with a subclass of it.
+
+    The registry caches a class after the first lookup, so the old
+    registration must go before the resolver can supply the subclass.
+  */
+  subclass<T extends object>(specifier: `${string}:${string}`, build: (Base: T) => T) {
+    let Base = this.application.resolveRegistration(specifier) as T;
+
+    this.application.unregister(specifier);
+    this.add(specifier, build(Base));
+  }
 }