Support setting returnvalue from mock to undefined (#3354)

Fixes #3320
jestjs · Apr 25, 2017 · f465fb6 · f465fb6
1 parent fa018cc
commit f465fb6
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diff --git a/packages/jest-mock/src/__tests__/jest-mock-test.js b/packages/jest-mock/src/__tests__/jest-mock-test.js
@@ -330,6 +330,26 @@ describe('moduleMocker', () => {
         expect(fn2()).not.toEqual('abcd');
       });
     });
+
+    it('supports mock value returning undefined', () => {
+      const obj = {
+        func: () => 'some text',
+      };
+
+      moduleMocker.spyOn(obj, 'func').mockReturnValue(undefined);
+
+      expect(obj.func()).not.toEqual('some text');
+    });
+
+    it('supports mock value once returning undefined', () => {
+      const obj = {
+        func: () => 'some text',
+      };
+
+      moduleMocker.spyOn(obj, 'func').mockReturnValueOnce(undefined);
+
+      expect(obj.func()).not.toEqual('some text');
+    });
   });
 
   describe('getMockImplementation', () => {

diff --git a/packages/jest-mock/src/index.js b/packages/jest-mock/src/index.js
@@ -274,6 +274,8 @@ class ModuleMockerClass {
           if (returnValue === undefined) {
             returnValue = mockConfig.defaultReturnValue;
           }
+
+          return returnValue;
         }
 
         // If mockImplementationOnce()/mockImplementation() is last set,