refactor: simplify after a codebase review

lib/src/cli/init_command.dart

@@ -79,7 +79,7 @@ class InitCommand(final ShutterContext context) extends Command<int> {
     } else {
       File(path)
         ..createSync(recursive: true)
-        ..writeAsStringSync(shellTemplate(project.dependencies).trimLeft());
+        ..writeAsStringSync(shellTemplate(project.dependencies));
       ShutterIO.stdoutSink.writeln('wrote    ${project.shown(path)}');
     }
     return 0;

lib/src/cli/shot_command.dart

@@ -198,9 +198,11 @@ class ShotCommand(final ShutterContext context) extends Command<int> {
       run: p.basename(runDir),
       shots: [...shots]..sort(Shot.bySource),
       shell: shellRecord,
-      actions: [for (final action in actions) action.label],
-      screen: screen,
-      viewport: viewport,
+      setup: (
+        actions: [for (final action in actions) action.label],
+        screen: screen,
+        viewport: viewport,
+      ),
     )..write(runDir);
     reportShots(manifest, runDir, ShutterIO.stdoutSink);
     return manifest.exitCode;

lib/src/engine/flutter_test_engine.dart

@@ -21,9 +21,9 @@ const _maxFontRounds = 3;
 /// `flutter test` exits 79 when a suite registers no tests.
 const _noTestsRan = 79;
 
-/// Engine v1: generates a `flutter_test` file under
-/// `.dart_tool/shutter/test/`, runs
-/// it with `flutter test`, and deletes it.
+/// Engine v1: generates a `flutter_test` suite in a per-run directory,
+/// `.dart_tool/shutter/test/<run-id>/`, runs it with `flutter test`, and
+/// deletes the directory.
 class FlutterTestEngine implements Engine {
   FlutterTestEngine({
     required this.sdk,
@@ -45,7 +45,12 @@ class FlutterTestEngine implements Engine {
     final googleFonts = request.project.packageRoot('google_fonts');
     final cache = FontCache(request.project.googleFontsDir, fetch: fetchFont);
     final design = DesignSupport.detect(request.project, sdk);
-    var pass = await _capture(request, design, cache.list());
+    var pass = await _capture(
+      request,
+      design,
+      cache.list(),
+      googleFonts: googleFonts != null,
+    );
     if (googleFonts == null) return pass.shots;
     final known = <String, GoogleFontFile>{};
     final failures = <String, String>{};
@@ -82,7 +87,7 @@ class FlutterTestEngine implements Engine {
 
       await Future.wait(pending.map(fetch));
       if (!added) break;
-      pass = await _capture(request, design, cache.list());
+      pass = await _capture(request, design, cache.list(), googleFonts: true);
     }
     return [
       for (final shot in pass.shots)
@@ -101,8 +106,9 @@ class FlutterTestEngine implements Engine {
   Future<({List<Shot> shots, Map<String, Set<String>> missingFonts})> _capture(
     CaptureRequest request,
     DesignSupport design,
-    List<CachedFont> fonts,
-  ) async {
+    List<CachedFont> fonts, {
+    required bool googleFonts,
+  }) async {
     final project = request.project;
     final shots = <Shot>[
       for (final library in request.libraries)
@@ -114,7 +120,7 @@ class FlutterTestEngine implements Engine {
         request: request,
         materialFontsDir: sdk.materialFontsDir,
         design: design,
-        googleFonts: project.packageRoot('google_fonts') != null,
+        googleFonts: googleFonts,
         fonts: fonts,
       ),
     );

lib/src/engine/generator.dart

@@ -38,7 +38,7 @@ class const GeneratorConfig({
 });
 
 /// Name of the helper library shooting [CaptureRequest.widget].
-const widgetHelper = 'widget';
+const _widgetHelper = 'widget';
 
 /// Writes `.dart_tool/shutter/test/<run-id>/`: the harness, the design library
 /// adapters, one helper library per source library (and one for the
@@ -65,9 +65,9 @@ String writeGeneratedTest(GeneratorConfig config) {
     helpers.add('l$i');
   }
   if (request.widget case final widget?) {
-    File(p.join(dir, 'sources', '$widgetHelper.dart'))
+    File(p.join(dir, 'sources', '$_widgetHelper.dart'))
         .writeAsStringSync(widget.helperSource());
-    helpers.add(widgetHelper);
+    helpers.add(_widgetHelper);
   }
 
   final testPath = p.join(dir, 'shutter_test.dart');

lib/src/engine/harness_text.dart

@@ -1,9 +1,9 @@
-/// Source of `.dart_tool/shutter/test/<run-id>/shutter_harness.dart`, the runtime
-/// half of the `flutter_test` engine. It is plain Flutter test code: it
-/// depends on `flutter` and `flutter_test` only, so the target project
-/// gains no dependency on shutter. The generated `shutter_test.dart` calls [run]
-/// with the scanned entries; each preview becomes one `testWidgets` that
-/// writes `<run>/<id>.png` and `<run>/.results/<id>.json`.
+/// Source of `.dart_tool/shutter/test/<run-id>/shutter_harness.dart`, the
+/// runtime half of the `flutter_test` engine. It is plain Flutter test code:
+/// it depends on `flutter` and `flutter_test` only, so the target project
+/// gains no dependency on shutter. The generated `shutter_test.dart` calls
+/// [run] with the scanned entries; each preview becomes one `testWidgets`
+/// that writes `<run>/<id>.png` and `<run>/.results/<id>.json`.
 ///
 /// The end-to-end tests under `test/e2e/` compile and run this text
 /// against `example/`.
@@ -196,8 +196,8 @@ Map<String, Object?> _entryFields(
 ) => {
   'id': id,
   'name': name,
-  if (entry.file != null) 'file': entry.file,
-  if (entry.line != null) 'line': entry.line,
+  'file': ?entry.file,
+  'line': ?entry.line,
 };
 
 /// `at` pointing at the declaration; none for an expression.
@@ -258,9 +258,8 @@ Future<void> _capture(
   };
   final result = <String, Object?>{
     ..._entryFields(entry, id, name),
-    if (preview.brightness != null) 'brightness': preview.brightness!.name,
-    if (preview.textScaleFactor != null)
-      'text_scale_factor': preview.textScaleFactor,
+    'brightness': ?preview.brightness?.name,
+    'text_scale_factor': ?preview.textScaleFactor,
   };
   LocalizationsResolver? resolver;
   // What undoes a held action: a pressed or hovering pointer, the focus

lib/src/engine/interaction.dart

@@ -47,18 +47,21 @@ class const ShotAction({
 }) {
   /// As given on the command line, and recorded in the manifest:
   /// `tap text:Save`, `enter key:name=Koji`.
-  String get label => switch (text) {
-    final text? => '${kind.name} ${by.name}:$value=$text',
-    null => '${kind.name} ${by.name}:$value',
-  };
+  String get label {
+    final text = switch (this.text) {
+      final text? => '=$text',
+      null => '',
+    };
+    return '${kind.name} ${by.name}:$value$text';
+  }
 
   /// The harness's `ShutterAction` for this action, as Dart source.
-  String get source => switch (text) {
-    final text? =>
-      '\$shutter.ShutterAction(.${kind.name}, .${by.name}, '
-          '${dartString(value)}, text: ${dartString(text)})',
-    null =>
-      '\$shutter.ShutterAction(.${kind.name}, .${by.name}, '
-          '${dartString(value)})',
-  };
+  String get source {
+    final text = switch (this.text) {
+      final text? => ', text: ${dartString(text)}',
+      null => '',
+    };
+    return '\$shutter.ShutterAction(.${kind.name}, .${by.name}, '
+        '${dartString(value)}$text)';
+  }
 }

lib/src/run/manifest.dart

@@ -129,15 +129,8 @@ class const RunManifest({
   /// The shell file, or null for the default shell.
   final ShellFile? shell,
 
-  /// The actions performed on every preview before the capture, as given
-  /// (`tap text:Save`).
-  final List<String> actions = const [],
-
-  /// The whole viewport was captured (`--capture screen`).
-  final bool screen = false,
-
-  /// The `--viewport` the shots were taken in.
-  final (double, double)? viewport,
+  /// What the run did besides rendering; see [RunSetup].
+  final RunSetup setup = plainSetup,
 }) {
   factory RunManifest.fromJson(Map<String, Object?> json) => RunManifest(
     run: json['run'] as String,
@@ -152,12 +145,14 @@ class const RunManifest({
       ),
       _ => null,
     },
-    actions: [...?(json['actions'] as List<Object?>?)?.cast<String>()],
-    screen: json['capture'] == 'screen',
-    viewport: switch (json['viewport']) {
-      [final num w, final num h] => (w.toDouble(), h.toDouble()),
-      _ => null,
-    },
+    setup: (
+      actions: [...?(json['actions'] as List<Object?>?)?.cast<String>()],
+      screen: json['capture'] == 'screen',
+      viewport: switch (json['viewport']) {
+        [final num w, final num h] => (w.toDouble(), h.toDouble()),
+        _ => null,
+      },
+    ),
   );
 
   /// Reads `<dir>/manifest.json`.
@@ -166,21 +161,22 @@ class const RunManifest({
         as Map<String, Object?>,
   );
 
-  RunSetup get setup => (actions: actions, screen: screen, viewport: viewport);
-
   /// 0 when every shot is ok, 2 when any is an `error`.
   int get exitCode => shots.any((s) => s.status == ShotStatus.error) ? 2 : 0;
 
-  Map<String, Object?> toJson() => {
-    'run': run,
-    if (shell case (:final path, :final sha256)?)
-      'shell': {'path': path, 'sha256': sha256},
-    if (actions.isNotEmpty) 'actions': actions,
-    if (screen) 'capture': 'screen',
-    if (viewport case (final w, final h)?)
-      'viewport': [jsonNumber(w), jsonNumber(h)],
-    'shots': [for (final shot in shots) shot.toJson()],
-  };
+  Map<String, Object?> toJson() {
+    final (:actions, :screen, :viewport) = setup;
+    return {
+      'run': run,
+      if (shell case (:final path, :final sha256)?)
+        'shell': {'path': path, 'sha256': sha256},
+      if (actions.isNotEmpty) 'actions': actions,
+      if (screen) 'capture': 'screen',
+      if (viewport case (final w, final h)?)
+        'viewport': [jsonNumber(w), jsonNumber(h)],
+      'shots': [for (final shot in shots) shot.toJson()],
+    };
+  }
 
   /// Writes `<dir>/manifest.json` as indented JSON.
   void write(String dir) => File(

lib/src/scan/candidate.dart

@@ -33,15 +33,13 @@ class Candidate({
   /// without being compiled.
   final String? error,
 }) {
-  /// First 16 hex of `sha256("<file>|<symbol>|<annotationIndex>")`.
-  String get staticId => shotStaticId(file, symbol, annotationIndex);
+  /// Static half of a shot id: the first 16 hex of
+  /// `sha256("<file>|<symbol>|<annotationIndex>")`. The runtime half (the
+  /// index of the `Preview` produced by `transform()`) is appended after
+  /// a `.`.
+  String get staticId => shortHash('$file|$symbol|$annotationIndex');
 }
 
-/// Static half of a shot id. The runtime half (the index of the
-/// `Preview` produced by `transform()`) is appended after a `.`.
-String shotStaticId(String file, String symbol, int annotationIndex) =>
-    shortHash('$file|$symbol|$annotationIndex');
-
 /// First 16 hex digits of `sha256(input)`.
 String shortHash(String input) =>
     sha256.convert(utf8.encode(input)).toString().substring(0, 16);

test/cli/misc_commands_test.dart

@@ -96,7 +96,7 @@ void main() {
     expect(first.stdout, 'wrote    lib/preview/shell.dart\n');
     expect(
       File(p.join(root, 'lib', 'preview', 'shell.dart')).readAsStringSync(),
-      shellTemplate(const {}).trimLeft(),
+      shellTemplate(const {}),
     );
     writeFiles(root, {'lib/preview/shell.dart': '// mine'});
     final second = await runCli(['init'], fakeContext(root));

test/cli/shot_command_test.dart

@@ -284,8 +284,9 @@ void main() {
     expect(report['capture'], 'screen');
     expect(report['viewport'], [390, 844]);
     final manifest = RunManifest.read(report['run'] as String);
-    expect(manifest.actions, labels);
-    expect((manifest.screen, manifest.viewport), (true, (390.0, 844.0)));
+    final setup = manifest.setup;
+    expect(setup.actions, labels);
+    expect((setup.screen, setup.viewport), (true, (390.0, 844.0)));
 
     for (final (flag, kind) in [
       ('--hover', ActionKind.hover),

test/diff/diff_engine_test.dart

@@ -41,9 +41,7 @@ void main() {
         run: 'pressed',
         shots: [],
         shell: (path: 'lib/preview/shell.dart', sha256: '1f2e'),
-        actions: ['press text:OK'],
-        screen: true,
-        viewport: (390, 844),
+        setup: (actions: ['press text:OK'], screen: true, viewport: (390, 844)),
       )..write(dir),
     );
     final diff = diffRuns(run('plain', const [], const {}), pressed);

test/reporters/shot_reporter_test.dart

@@ -83,9 +83,11 @@ shots:
       const RunManifest(
         run: 'r',
         shots: [],
-        actions: ['tap text:Open', 'press key:save'],
-        screen: true,
-        viewport: (390, 844),
+        setup: (
+          actions: ['tap text:Open', 'press key:save'],
+          screen: true,
+          viewport: (390, 844),
+        ),
       ),
     );
     expect(
@@ -99,7 +101,11 @@ shots:
       ),
     );
     final screenOnly = await render(
-      const RunManifest(run: 'r', shots: [], screen: true),
+      const RunManifest(
+        run: 'r',
+        shots: [],
+        setup: (actions: [], screen: true, viewport: null),
+      ),
     );
     expect(screenOnly, contains('shell: default\ncapture: screen\nsummary:'));
   });

test/run/manifest_test.dart

@@ -76,9 +76,11 @@ void main() {
     const RunManifest(
       run: 'r',
       shots: [],
-      actions: ['tap text:Open', 'press key:save'],
-      screen: true,
-      viewport: (390, 844.5),
+      setup: (
+        actions: ['tap text:Open', 'press key:save'],
+        screen: true,
+        viewport: (390, 844.5),
+      ),
     ).write(dir);
     final back = RunManifest.read(dir);
     final setup = back.setup;

test/scan/candidate_test.dart

@@ -4,6 +4,15 @@ import 'package:test/test.dart';
 void main() {
   test('static id is the first 16 hex of sha256(file|symbol|index)', () {
     // Ids pair shots across runs, so the formula must not drift.
-    expect(shotStaticId('lib/a.dart', 'a', 0), 'e815cfe43338aced');
+    final candidate = Candidate(
+      file: 'lib/a.dart',
+      line: 1,
+      column: 1,
+      symbol: 'a',
+      annotationIndex: 0,
+      annotation: '',
+      target: '',
+    );
+    expect(candidate.staticId, 'e815cfe43338aced');
   });
 }

test/scan/scanner_test.dart

@@ -57,7 +57,7 @@ class Button extends Widget {
     );
     expect(c.target, r'$i2.a');
     expect(c.error, isNull);
-    expect(c.staticId, shotStaticId('lib/preview/a.dart', 'a', 0));
+    expect(c.staticId, shortHash('lib/preview/a.dart|a|0'));
   });
 
   test('only Flutter\'s Preview and MultiPreview make previews; a '