feat: MockHelper with find, findAll and OrFail

README.md

@@ -442,10 +442,18 @@ MockHelper provides 3 methods to get attribute and structural directives from an
 returns attribute or structural directive which belongs to current element.
 
 `MockHelper.findDirective(fixture.debugElement, Directive)` -
-returns first found attribute or structural directive which belongs to current element or any child.
+returns the first found attribute or structural directive which belongs to current element or any child.
 
 `MockHelper.findDirectives(fixture.debugElement, Directive)` -
-returns all found attribute or structural directives which belong to current element and all its child.
+returns an array of all found attribute or structural directives which belong to current element and all its child.
+
+`MockHelper.find(fixture.debugElement, Component)` -
+returns a found DebugElement which belongs to the Component with the correctly typed componentInstance or null.
+
+`MockHelper.findAll(fixture.debugElement, Component)` -
+returns an array of found DebugElements which belong to the Component with the correctly typed componentInstance.
+
+`getDirective`, `findDirective` and `find` have `OrFail` version that throws an error if the desired element wasn't found.
 
 `MockHelper.mockService(instance, methodName)` -
 returns a mocked function / spy of the method. If the method hasn't been mocked yet - mocks it.

lib/mock-helper/mock-helper.spec.ts

@@ -1,6 +1,6 @@
 // tslint:disable:max-classes-per-file
 
-import { Directive, EventEmitter, Input, Output } from '@angular/core';
+import { Component, Directive, EventEmitter, Input, Output } from '@angular/core';
 import { async, TestBed } from '@angular/core/testing';
 import { By } from '@angular/platform-browser';
 
@@ -30,10 +30,29 @@ export class ExampleStructuralDirective {
   @Input() exampleStructuralDirective = true;
 }
 
+@Component({
+  selector: 'component-a',
+  template: 'body-a',
+})
+export class AComponent {
+}
+
+@Component({
+  selector: 'component-b',
+  template: 'body-b',
+})
+export class BComponent {
+}
+
 describe('MockHelper:getDirective', () => {
   beforeEach(async(() => {
     TestBed.configureTestingModule({
-      declarations: [MockDirective(ExampleDirective), MockDirective(ExampleStructuralDirective)],
+      declarations: [
+        MockDirective(ExampleDirective),
+        MockDirective(ExampleStructuralDirective),
+        AComponent,
+        BComponent,
+      ],
     });
   }));
 
@@ -57,7 +76,7 @@ describe('MockHelper:getDirective', () => {
     expect(elementFromHelper).toBe(element);
   });
 
-  it('should return right structural directive', () => {
+  it('should return right structural directive via getDirective', () => {
     const fixture = MockRender(`
       <div id="example-structural-directive" *exampleStructuralDirective="false">hi</div>
     `);
@@ -83,4 +102,85 @@ describe('MockHelper:getDirective', () => {
     // Verification.
     expect(elementFromHelper.exampleStructuralDirective).toEqual(false);
   });
+
+  it('should return right structural directive via getDirectiveOrFail', () => {
+    const fixture = MockRender(`
+      <div id="example-structural-directive" *exampleStructuralDirective="false">hi</div>
+    `);
+
+    // we need to render mocked structural directives manually
+    MockHelper.findDirectives(fixture.debugElement, ExampleStructuralDirective).forEach(
+      (item: MockedDirective<ExampleStructuralDirective>) => {
+        item.__render();
+      }
+    );
+    fixture.detectChanges();
+
+    // Using helper.
+    const elementFromHelper = MockHelper.getDirectiveOrFail(
+      fixture.debugElement.query(By.css('div')),
+      ExampleStructuralDirective
+    );
+
+    // Verification.
+    expect(elementFromHelper.exampleStructuralDirective).toEqual(false);
+  });
+
+  it('find selector: T', () => {
+    const fixture = MockRender(`<component-a></component-a>`);
+    const componentA = MockHelper.findOrFail(fixture.debugElement, AComponent);
+    expect(componentA.componentInstance).toEqual(jasmine.any(AComponent));
+
+    expect(() => MockHelper.findOrFail(componentA, BComponent))
+      .toThrowError('Cannot find an element via MockHelper.findOrFail');
+  });
+
+  it('find selector: string', () => {
+    const fixture = MockRender(`<component-b></component-b>`);
+    const componentB = MockHelper.findOrFail(fixture.debugElement, 'component-b');
+    expect(componentB.componentInstance).toEqual(jasmine.any(BComponent));
+
+    expect(() => MockHelper.findOrFail(componentB, AComponent))
+      .toThrowError('Cannot find an element via MockHelper.findOrFail');
+  });
+
+  it('find selector: T', () => {
+    const fixture = MockRender(`<component-a></component-a>`);
+    const componentA = MockHelper.find(fixture.debugElement, AComponent);
+    expect(componentA && componentA.componentInstance).toEqual(jasmine.any(AComponent));
+
+    const componentB = MockHelper.find(fixture.debugElement, BComponent);
+    expect(componentB).toBe(null); // tslint:disable-line:no-null-keyword
+  });
+
+  it('find selector: string', () => {
+    const fixture = MockRender(`<component-b></component-b>`);
+    const componentB = MockHelper.find(fixture.debugElement, 'component-b');
+    expect(componentB && componentB.componentInstance).toEqual(jasmine.any(BComponent));
+
+    const componentA = MockHelper.find(fixture.debugElement, 'component-a');
+    expect(componentA).toBe(null); // tslint:disable-line:no-null-keyword
+  });
+
+  it('findAll selector: T', () => {
+    const fixture = MockRender(`<component-a></component-a><component-a></component-a>`);
+    const componentA = MockHelper.findAll(fixture.debugElement, AComponent);
+    expect(componentA.length).toBe(2); // tslint:disable-line:no-magic-numbers
+    expect(componentA[0].componentInstance).toEqual(jasmine.any(AComponent));
+    expect(componentA[1].componentInstance).toEqual(jasmine.any(AComponent));
+
+    const componentB = MockHelper.findAll(fixture.debugElement, BComponent);
+    expect(componentB.length).toBe(0);
+  });
+
+  it('findAll selector: string', () => {
+    const fixture = MockRender(`<component-b></component-b><component-b></component-b>`);
+    const componentB = MockHelper.findAll(fixture.debugElement, 'component-b');
+    expect(componentB.length).toEqual(2); // tslint:disable-line:no-magic-numbers
+    expect(componentB[0].componentInstance).toEqual(jasmine.any(BComponent));
+    expect(componentB[0].componentInstance).toEqual(jasmine.any(BComponent));
+
+    const componentA = MockHelper.findAll(fixture.debugElement, 'component-a');
+    expect(componentA.length).toBe(0);
+  });
 });

lib/mock-helper/mock-helper.ts

@@ -1,7 +1,9 @@
 /* tslint:disable:variable-name */
 
 import { DebugNode, Type } from '@angular/core';
+import { By } from '@angular/platform-browser';
 
+import { DebugElementType } from '../mock-render';
 import { MockedFunction, mockServiceHelper } from '../mock-service';
 
 interface INestedNodes extends DebugNode {
@@ -19,7 +21,28 @@ function nestedCheck<T>(result: T[], node: INestedNodes, callback: (node: INeste
   });
 }
 
-export const MockHelper = {
+export const MockHelper: {
+  find<T>(debugElement: DebugElementType<any>, component: Type<T>): null | DebugElementType<T>;
+  find(debugElement: DebugElementType<any>, cssSelector: string): null | DebugElementType<any>;
+  findAll<T>(debugElement: DebugElementType<any>, component: Type<T>): Array<DebugElementType<T>>;
+  findAll(debugElement: DebugElementType<any>, cssSelector: string): Array<DebugElementType<any>>;
+  findDirective<T>(debugNode: DebugNode, directive: Type<T>): undefined | T;
+  findDirectiveOrFail<T>(debugNode: DebugNode, directive: Type<T>): T;
+  findDirectives<T>(debugNode: DebugNode, directive: Type<T>): T[];
+  findOrFail<T>(debugElement: DebugElementType<any>, component: Type<T>): DebugElementType<T>;
+  findOrFail(debugElement: DebugElementType<any>, cssSelector: string): DebugElementType<any>;
+  getDirective<T>(debugNode: DebugNode, directive: Type<T>): undefined | T;
+  getDirectiveOrFail<T>(debugNode: DebugNode, directive: Type<T>): T;
+  mockService<T = MockedFunction>(instance: any, name: string, style?: 'get' | 'set'): T;
+} = {
+  getDirectiveOrFail: <T>(debugNode: DebugNode, directive: Type<T>): T => {
+    const result = MockHelper.getDirective(debugNode, directive);
+    if (!result) {
+      throw new Error(`Cannot find a directive via MockHelper.getDirectiveOrFail`);
+    }
+    return result;
+  },
+
   getDirective: <T>(debugNode: DebugNode, directive: Type<T>): undefined | T => {
     // Looking for related attribute directive.
     try {
@@ -49,6 +72,14 @@ export const MockHelper = {
     }
   },
 
+  findDirectiveOrFail: <T>(debugNode: DebugNode, directive: Type<T>): T => {
+    const result = MockHelper.findDirective(debugNode, directive);
+    if (!result) {
+      throw new Error(`Cannot find a directive via MockHelper.findDirectiveOrFail`);
+    }
+    return result;
+  },
+
   findDirective: <T>(debugNode: DebugNode, directive: Type<T>): undefined | T => {
     const result: T[] = [];
     nestedCheck<T>(result, debugNode, node => {
@@ -73,6 +104,24 @@ export const MockHelper = {
     return result;
   },
 
+  findOrFail: (el: DebugElementType<any>, sel: any) => {
+    const result = MockHelper.find(el, sel);
+    if (!result) {
+      throw new Error(`Cannot find an element via MockHelper.findOrFail`);
+    }
+    return result;
+  },
+
+  find: (el: DebugElementType<any>, sel: any) => {
+    const term = typeof sel === 'string' ? By.css(sel) : By.directive(sel);
+    return el.query(term);
+  },
+
+  findAll: (el: DebugElementType<any>, sel: any) => {
+    const term = typeof sel === 'string' ? By.css(sel) : By.directive(sel);
+    return el.queryAll(term);
+  },
+
   mockService: <T = MockedFunction>(instance: any, name: string, style?: 'get' | 'set'): T =>
     mockServiceHelper.mock(instance, name, style),
 };