Changed mockName() API to return the current mock name via a separate…

… getMockName() instead of overloading mockName() function to return it when no arguments are passed

docs/en/MockFunctionAPI.md

@@ -18,6 +18,9 @@ Mock functions are also known as "spies", because they let you spy on the behavi
 
 ## Reference
 
+### `mockFn.getMockName()`
+Returns the mock name string set by calling `mockFn.mockName(value)`
+
 ### `mockFn.mock.calls`
 An array that represents all calls that have been made into this mock function. Each call is represented by an array of arguments that were passed during the call.
 

packages/expect/src/spy_matchers.js

@@ -31,7 +31,7 @@ const createToBeCalledMatcher = matcherName => (received, expected) => {
 
   const receivedIsSpy = isSpy(received);
   const type = receivedIsSpy ? 'spy' : 'mock function';
-  const receivedName = receivedIsSpy ? 'spy' : received.mockName();
+  const receivedName = receivedIsSpy ? 'spy' : received.getMockName();
   const count = receivedIsSpy
     ? received.calls.count()
     : received.mock.calls.length;
@@ -61,7 +61,7 @@ const createToBeCalledWithMatcher = matcherName => (
 
   const receivedIsSpy = isSpy(received);
   const type = receivedIsSpy ? 'spy' : 'mock function';
-  const receivedName = receivedIsSpy ? 'spy' : received.mockName();
+  const receivedName = receivedIsSpy ? 'spy' : received.getMockName();
   const calls = receivedIsSpy
     ? received.calls.all().map(x => x.args)
     : received.mock.calls;
@@ -94,7 +94,7 @@ const createLastCalledWithMatcher = matcherName => (
 
   const receivedIsSpy = isSpy(received);
   const type = receivedIsSpy ? 'spy' : 'mock function';
-  const receivedName = receivedIsSpy ? 'spy' : received.mockName();
+  const receivedName = receivedIsSpy ? 'spy' : received.getMockName();
   const calls = receivedIsSpy
     ? received.calls.all().map(x => x.args)
     : received.mock.calls;
@@ -127,7 +127,7 @@ const spyMatchers: MatchersObject = {
 
     const receivedIsSpy = isSpy(received);
     const type = receivedIsSpy ? 'spy' : 'mock function';
-    const receivedName = receivedIsSpy ? 'spy' : received.mockName();
+    const receivedName = receivedIsSpy ? 'spy' : received.getMockName();
     const count = receivedIsSpy
       ? received.calls.count()
       : received.mock.calls.length;

packages/jest-mock/src/__tests__/jest_mock.test.js

@@ -458,36 +458,40 @@ describe('moduleMocker', () => {
     expect(moduleMocker.isMockFunction(mockFn)).toBe(true);
   });
 
+  test('default mockName is jest.fn()', () => {
+    const fn = jest.fn();
+    expect(fn.getMockName()).toBe('jest.fn()');
+  });
+
   test('mockName sets the mock name', () => {
     const fn = jest.fn();
-    expect(fn.mockName()).toBe('jest.fn()');
     fn.mockName('myMockFn');
-    expect(fn.mockName()).toBe('myMockFn');
+    expect(fn.getMockName()).toBe('myMockFn');
   });
 
   test('mockName gets reset by mockReset', () => {
     const fn = jest.fn();
-    expect(fn.mockName()).toBe('jest.fn()');
+    expect(fn.getMockName()).toBe('jest.fn()');
     fn.mockName('myMockFn');
-    expect(fn.mockName()).toBe('myMockFn');
+    expect(fn.getMockName()).toBe('myMockFn');
     fn.mockReset();
-    expect(fn.mockName()).toBe('jest.fn()');
+    expect(fn.getMockName()).toBe('jest.fn()');
   });
 
   test('mockName is not reset by mockRestore', () => {
     const fn = jest.fn(() => false);
     fn.mockName('myMockFn');
-    expect(fn.mockName()).toBe('myMockFn');
+    expect(fn.getMockName()).toBe('myMockFn');
     fn.mockRestore();
-    expect(fn.mockName()).toBe('myMockFn');
+    expect(fn.getMockName()).toBe('myMockFn');
   });
 
   test('mockName is not reset by mockClear', () => {
     const fn = jest.fn(() => false);
     fn.mockName('myMockFn');
-    expect(fn.mockName()).toBe('myMockFn');
+    expect(fn.getMockName()).toBe('myMockFn');
     fn.mockClear();
-    expect(fn.mockName()).toBe('myMockFn');
+    expect(fn.getMockName()).toBe('myMockFn');
   });
 
   describe('spyOn', () => {

packages/jest-mock/src/index.js

@@ -436,14 +436,16 @@ class ModuleMockerClass {
         });
 
       f.mockName = name => {
-        if (arguments.length > 0 && name) {
+        if (name) {
           const mockConfig = this._ensureMockConfig(f);
           mockConfig.mockName = name;
-          return f;
-        } else {
-          const mockConfig = this._ensureMockConfig(f);
-          return mockConfig.mockName || 'jest.fn()';
         }
+        return f;
+      };
+
+      f.getMockName = () => {
+        const mockConfig = this._ensureMockConfig(f);
+        return mockConfig.mockName || 'jest.fn()';
       };
 
       if (metadata.mockImpl) {