feat(nested mock): expand PR 884 with tests (#1075)

Author: JacobSiegle

packages/testing/ts-jest/src/mocks.spec.ts

@@ -10,16 +10,28 @@ interface TestInterface {
   func: (num: number, str: string) => boolean;
   func2: (entity: TestClass) => void;
   func3: () => Promise<{ prop: number }>;
+  nested: {
+    someOtherNum: number;
+    func4: () => boolean;
+  };
 }
 
 class TestClass {
   someProperty!: number;
 
+  nested = new NestedTestClass();
+
   someMethod() {
     return 42;
   }
 }
 
+class NestedTestClass {
+  someOtherMethod() {
+    return 24;
+  }
+}
+
 describe('Mocks', () => {
   const request = {
     headers: {
@@ -200,6 +212,22 @@ describe('Mocks', () => {
       expect(serviceMock.foo()).toEqual(false);
       expect(serviceMock.foo()).toEqual(true);
     });
+
+    it('should work with nested properties and functions', () => {
+      const mock = createMock<TestInterface>();
+      mock.nested.someOtherNum = 99;
+      mock.nested.func4.mockReturnValueOnce(true);
+      const result = mock.nested.func4();
+      expect(mock.nested.someOtherNum).toBe(99);
+      expect(result).toBe(true);
+    });
+
+    it('should work with classes having nested properties', () => {
+      const mock = createMock<TestClass>();
+      mock.nested.someOtherMethod.mockReturnValueOnce(99);
+      const result = mock.nested.someOtherMethod();
+      expect(result).toBe(99);
+    });
   });
 
   describe('auto mocked', () => {
@@ -360,7 +388,9 @@ describe('Mocks', () => {
       it('should throw error when calling unstubbed method in strict mode', () => {
         const mock = createMock<TestInterface>({}, { strict: true });
 
-        expect(() => mock.func(1, 'test')).toThrow('Method mock.func was called without being explicitly stubbed');
+        expect(() => mock.func(1, 'test')).toThrow(
+          'Method mock.func was called without being explicitly stubbed',
+        );
 
         mock.func.mockReturnValue(true);
         expect(mock.func(1, 'test')).toBe(true);

packages/testing/ts-jest/src/mocks.ts

@@ -21,7 +21,7 @@ export type DeepMocked<T> = {
   [K in keyof T]: Required<T>[K] extends (...args: any[]) => infer U
     ? jest.MockInstance<ReturnType<Required<T>[K]>, jest.ArgsType<T[K]>> &
         ((...args: jest.ArgsType<T[K]>) => DeepMocked<U>)
-    : T[K];
+    : DeepMocked<T[K]>;
 } & T;
 
 const jestFnProps = new Set([
@@ -49,7 +49,11 @@ const jestFnProps = new Set([
 const createProxy: {
   <T extends object>(name: string, strict: boolean, base: T): T;
   <T extends Mock<any, any> = Mock<any, any>>(name: string, strict: boolean): T;
-} = <T extends object | Mock<any, any>>(name: string, strict: boolean, base?: T): T => {
+} = <T extends object | Mock<any, any>>(
+  name: string,
+  strict: boolean,
+  base?: T,
+): T => {
   const cache = new Map<string | number | symbol, any>();
   const handler: ProxyHandler<T> = {
     get: (obj, prop, receiver) => {
@@ -105,7 +109,9 @@ const createProxy: {
         return result;
       } else {
         if (strict) {
-          throw new Error(`Method ${name} was called without being explicitly stubbed`);
+          throw new Error(
+            `Method ${name} was called without being explicitly stubbed`,
+          );
         }
         if (!cache.has('__apply')) {
           cache.set('__apply', createProxy(name, strict));