Merge pull request #2099 from satanTime/issues/919

tests(MockRender): covering change detection behavior #919

tests/issue-919/test.spec.ts

@@ -0,0 +1,44 @@
+import { CommonModule } from '@angular/common';
+import { Component, NgModule } from '@angular/core';
+import { MockBuilder, MockRender, ngMocks } from 'ng-mocks';
+import { BehaviorSubject, Observable } from 'rxjs';
+
+@Component({
+  selector: 'target',
+  template: `<ng-container *ngIf="context.data$ | async as data">{{
+    data.value
+  }}</ng-container>`,
+})
+class TargetComponent {
+  public context:
+    | {
+        data$: Observable<{ value: string }>;
+      }
+    | any;
+}
+
+@NgModule({
+  declarations: [TargetComponent],
+  imports: [CommonModule],
+})
+class TargetModule {}
+
+// The goal is to provide properties before the real render.
+// @see https://github.com/ike18t/ng-mocks/issues/919
+describe('issue-919', () => {
+  beforeEach(() => MockBuilder(TargetComponent, TargetModule));
+
+  it('allows to change the component before render', () => {
+    const fixture = MockRender(TargetComponent, {}, false);
+    fixture.point.componentInstance.context = {
+      data$: new BehaviorSubject({ value: 'positive' }),
+    };
+    fixture.detectChanges();
+
+    expect(ngMocks.formatText(fixture)).toEqual('positive');
+  });
+
+  it('fails on render', () => {
+    expect(() => MockRender(TargetComponent)).toThrowError(/data\$/);
+  });
+});