unit test

Author: Rosie Ellis

SingularityService/src/main/java/com/hubspot/singularity/config/SingularityConfiguration.java

@@ -2136,7 +2136,7 @@ public boolean allowEmptyRequestInstances() {
     return allowEmptyRequestInstances;
   }
 
-  public void setallowEmptyRequestInstances(boolean allowEmptyRequestInstances) {
+  public void setAllowEmptyRequestInstances(boolean allowEmptyRequestInstances) {
     this.allowEmptyRequestInstances = allowEmptyRequestInstances;
   }
 }

SingularityService/src/main/java/com/hubspot/singularity/data/SingularityValidator.java

@@ -231,16 +231,12 @@ public SingularityRequest checkSingularityRequest(
       request.getId()
     );
 
-    if (singularityConfiguration.allowEmptyRequestInstances()) {
-      checkBadRequest(
-        (
-          !existingRequest.flatMap(SingularityRequest::getInstances).isPresent() &&
-          !request.getInstances().isPresent()
-        ) ||
-        request.getInstances().get() > 0,
-        "Instances must be greater than 0"
-      );
+    checkBadRequest(
+      !request.getInstances().isPresent() || request.getInstances().get() > 0,
+      "Instances must be greater than 0"
+    );
 
+    if (singularityConfiguration.allowEmptyRequestInstances()) {
       if (
         (
           request.getRequestType().equals(RequestType.SERVICE) ||
@@ -252,11 +248,6 @@ public SingularityRequest checkSingularityRequest(
         request =
           request.toBuilder().setInstances(existingRequest.get().getInstances()).build();
       }
-    } else {
-      checkBadRequest(
-        !request.getInstances().isPresent() || request.getInstances().get() > 0,
-        "Instances must be greater than 0"
-      );
     }
 
     checkBadRequest(

SingularityService/src/test/java/com/hubspot/singularity/data/ValidatorTest.java

@@ -562,4 +562,30 @@ public void itDoesNotAllowOtherRequestTypesToChange() {
         )
     );
   }
+
+  @Test
+  public void itKeepPreviousInstancesCountWhenEmpty() {
+    singularityConfiguration.setAllowEmptyRequestInstances(true);
+    SingularityRequest request = new SingularityRequestBuilder("test", RequestType.WORKER)
+      .setInstances(Optional.of(5))
+      .build();
+    SingularityRequest newRequest = new SingularityRequestBuilder(
+      "test",
+      RequestType.WORKER
+    )
+    .build();
+
+    SingularityRequest returnedRequest = validator.checkSingularityRequest(
+      newRequest,
+      Optional.of(request),
+      Optional.empty(),
+      Optional.empty()
+    );
+
+    Assertions.assertTrue(returnedRequest.getInstances().isPresent());
+    Assertions.assertSame(
+      returnedRequest.getInstances().get(),
+      request.getInstances().get()
+    );
+  }
 }