From 68fc5da74b0f96949013c1aef60eb07db39fb2ee Mon Sep 17 00:00:00 2001
From: ersimont <8042088+ersimont@users.noreply.github.com>
Date: Fri, 13 Nov 2020 16:47:27 -0500
Subject: [PATCH] feat(ng-dev): `AngularContext.tick()` better simulates real
 change detection

---
 .../lib/test-context/angular-context.spec.ts  | 46 +++++++++++++++----
 .../src/lib/test-context/angular-context.ts   |  1 +
 .../src/lib/test-context/component-context.ts |  2 +-
 3 files changed, 38 insertions(+), 11 deletions(-)

diff --git a/projects/ng-dev/src/lib/test-context/angular-context.spec.ts b/projects/ng-dev/src/lib/test-context/angular-context.spec.ts
index 855f5a71..0857aeda 100644
--- a/projects/ng-dev/src/lib/test-context/angular-context.spec.ts
+++ b/projects/ng-dev/src/lib/test-context/angular-context.spec.ts
@@ -154,12 +154,12 @@ describe('AngularContext', () => {
     });
 
     it('runs change detection even if no tasks are queued', () => {
-      let changeDetectionCount = 0;
+      let ranChangeDetection = false;
 
       @Component({ template: '' })
       class LocalComponent implements DoCheck {
         ngDoCheck(): void {
-          ++changeDetectionCount;
+          ranChangeDetection = true;
         }
       }
       TestBed.overrideComponent(LocalComponent, {});
@@ -170,20 +170,20 @@ describe('AngularContext', () => {
         const componentRef = factory.create(ctx.inject(Injector));
         ctx.inject(ApplicationRef).attachView(componentRef.hostView);
 
-        expect(changeDetectionCount).toBe(0);
+        expect(ranChangeDetection).toBe(false);
         ctx.tick();
-        expect(changeDetectionCount).toBe(1);
+        expect(ranChangeDetection).toBe(true);
       });
     });
 
     it('flushes micro tasks before running change detection', () => {
-      let promiseResolved = false;
-      let promiseResolvedBeforeChangeDetection = false;
+      let ranChangeDetection = false;
+      let flushedMicroTasksBeforeChangeDetection = false;
 
       @Component({ template: '' })
       class LocalComponent implements DoCheck {
         ngDoCheck(): void {
-          promiseResolvedBeforeChangeDetection = promiseResolved;
+          ranChangeDetection = true;
         }
       }
       TestBed.overrideComponent(LocalComponent, {});
@@ -195,14 +195,40 @@ describe('AngularContext', () => {
         ctx.inject(ApplicationRef).attachView(componentRef.hostView);
 
         Promise.resolve().then(() => {
-          promiseResolved = true;
+          flushedMicroTasksBeforeChangeDetection = !ranChangeDetection;
         });
         ctx.tick();
-        expect(promiseResolvedBeforeChangeDetection).toBe(true);
+        expect(flushedMicroTasksBeforeChangeDetection).toBe(true);
       });
     });
 
-    it('advances `performance.now()` as well', () => {
+    it('runs change detection after timeouts', () => {
+      let ranTimeout = false;
+      let ranChangeDetectionAfterTimeout = false;
+
+      @Component({ template: '' })
+      class LocalComponent implements DoCheck {
+        ngDoCheck(): void {
+          ranChangeDetectionAfterTimeout = ranTimeout;
+        }
+      }
+      TestBed.overrideComponent(LocalComponent, {});
+
+      ctx.run(() => {
+        const resolver = ctx.inject(ComponentFactoryResolver);
+        const factory = resolver.resolveComponentFactory(LocalComponent);
+        const componentRef = factory.create(ctx.inject(Injector));
+        ctx.inject(ApplicationRef).attachView(componentRef.hostView);
+
+        setTimeout(() => {
+          ranTimeout = true;
+        });
+        ctx.tick();
+        expect(ranChangeDetectionAfterTimeout).toBe(true);
+      });
+    });
+
+    it('advances `performance.now()`', () => {
       ctx.run(() => {
         const start = performance.now();
         ctx.tick(10);
diff --git a/projects/ng-dev/src/lib/test-context/angular-context.ts b/projects/ng-dev/src/lib/test-context/angular-context.ts
index ef63fe6e..dcdd0c10 100644
--- a/projects/ng-dev/src/lib/test-context/angular-context.ts
+++ b/projects/ng-dev/src/lib/test-context/angular-context.ts
@@ -188,6 +188,7 @@ export class AngularContext<InitOptions = {}> {
     this.runChangeDetection();
 
     tick(convertTime(amount, unit, 'ms'));
+    this.runChangeDetection();
   }
 
   /**
diff --git a/projects/ng-dev/src/lib/test-context/component-context.ts b/projects/ng-dev/src/lib/test-context/component-context.ts
index ba215f08..0e49175d 100644
--- a/projects/ng-dev/src/lib/test-context/component-context.ts
+++ b/projects/ng-dev/src/lib/test-context/component-context.ts
@@ -59,7 +59,7 @@ export abstract class ComponentContext<
   protected abstract componentType: Type<ComponentType>;
 
   /**
-   * @param moduleMetadata passed along to [TestBed.configureTestingModule()]{@linkcode https://angular.io/api/core/testing/TestBed#configureTestingModule}. Automatically includes {@link NoopAnimationsModule} and {@link HttpClientTestingModule} for you.
+   * @param moduleMetadata passed along to [TestBed.configureTestingModule()]{@linkcode https://angular.io/api/core/testing/TestBed#configureTestingModule}. Automatically includes {@link NoopAnimationsModule}, in addition to those provided by {@link AngularContext}.
    */
   constructor(moduleMetadata: TestModuleMetadata = {}) {
     super(extendMetadata(moduleMetadata, { imports: [NoopAnimationsModule] }));