Merge pull request #2096 from satanTime/issues/2087

fix(MockInstance): correctly accepts falsy values #2087

Author: satanTime

libs/ng-mocks/src/lib/mock-instance/mock-instance.ts

@@ -42,8 +42,8 @@ const parseMockInstanceArgs = (args: any[]): MockInstanceArgs => {
     set.accessor = args[2];
   } else {
     set.value = args[0];
-    if (typeof set.value !== 'function') {
-      set.value = set.value?.init;
+    if (set.value && typeof set.value === 'object') {
+      set.value = set.value.init;
     }
   }
 
@@ -177,9 +177,9 @@ export function MockInstance<T>(
 export function MockInstance<T>(declaration: Type<T> | AbstractType<T> | InjectionToken<T>, ...args: any[]) {
   funcImportExists(declaration, 'MockInstance');
 
-  const { key, value, accessor } = parseMockInstanceArgs(args);
+  if (args.length) {
+    const { key, value, accessor } = parseMockInstanceArgs(args);
 
-  if (value) {
     return mockInstanceConfig(declaration, key, value, accessor);
   }
 

tests/issue-2087/test.spec.ts

@@ -0,0 +1,60 @@
+import { CommonModule } from '@angular/common';
+import { Component, Directive, NgModule } from '@angular/core';
+import {
+  MockBuilder,
+  MockInstance,
+  MockProvider,
+  MockRender,
+} from 'ng-mocks';
+
+@Directive({
+  selector: 'target',
+})
+class MockDirective {
+  public readonly boolean = false;
+  public readonly number = 0;
+  public readonly string = '';
+}
+
+@Component({
+  selector: 'target',
+  template: ``,
+})
+class TargetComponent {
+  public constructor(public readonly mock: MockDirective) {}
+}
+
+@NgModule({
+  declarations: [TargetComponent, MockDirective],
+  imports: [CommonModule],
+})
+class TargetModule {}
+
+// MockInstance doesn't provide falsy values.
+// @see https://github.com/ike18t/ng-mocks/issues/2087
+describe('issue-2087', () => {
+  MockInstance.scope();
+  beforeEach(() => MockBuilder(TargetComponent, TargetModule));
+
+  const tests: Array<[keyof MockDirective, any, any]> = [
+    ['string', '', 'test'],
+    ['number', 0, 1],
+    ['boolean', false, true],
+  ];
+
+  tests.forEach(([kind, falsy, truthy]) =>
+    describe(kind, () => {
+      it(`works for falsy`, () => {
+        MockInstance(MockDirective, kind, falsy);
+        const fixture = MockRender(TargetComponent);
+        expect(fixture.componentInstance.mock[kind]).toEqual(falsy);
+      });
+
+      it(`works for truthy`, () => {
+        MockInstance(MockDirective, kind, truthy);
+        const fixture = MockRender(TargetComponent);
+        expect(fixture.componentInstance.mock[kind]).toEqual(truthy);
+      });
+    }),
+  );
+});