Fix toString bug

morganstanley · May 19, 2022 · f379b36 · f379b36
1 parent a5b0fcf
commit f379b36
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Showing 3 changed files with 27 additions and 3 deletions.
diff --git a/main/mock/operators.ts b/main/mock/operators.ts
@@ -43,7 +43,10 @@ export function setupFunction<T, C extends ConstructorFunction<T>, U extends Fun
             mocked.functionReplacementLookup['function'] || {});
         functionLookup[functionName as string] = mockFunction;
 
-        if (mocked.mock[functionName] == null) {
+        // we do not replace an existing function in case it has already been destructured and sut already has a reference to it
+        // we do replace the mocked implementation above though
+        // eslint-disable-next-line @typescript-eslint/ban-types
+        if ((mocked.mock[functionName] as Function)?.name != functionReplacement.name) {
             mocked.mock[functionName] = functionReplacement as any;
         }
         mocked.functionCallLookup[functionName] = [];
@@ -53,7 +56,7 @@ export function setupFunction<T, C extends ConstructorFunction<T>, U extends Fun
 }
 
 /**
- * Mocks a staticfunction on an existing Mock.
+ * Mocks a static function on an existing Mock.
  * Allows function call verification to be performed later in the test.
  * You can optionally set a mock function implementation that will be called.
  *
@@ -83,7 +86,8 @@ export function setupStaticFunction<
             mocked.functionReplacementLookup['staticFunction'] || {});
         staticFunctionLookup[functionName as string] = mockFunction;
 
-        if (mocked.mockConstructor[functionName] == null) {
+        // eslint-disable-next-line @typescript-eslint/ban-types
+        if ((mocked.mockConstructor[functionName] as Function)?.name != functionReplacement.name) {
             mocked.mockConstructor[functionName] = functionReplacement as any;
         }
         mocked.staticFunctionCallLookup[functionName] = [];

diff --git a/spec/mock/mock-static.spec.ts b/spec/mock/mock-static.spec.ts
@@ -1445,6 +1445,15 @@ describe('mock with statics', () => {
             expect(newMock.mockConstructor.functionWithParamsAndNoReturn('', 123, true)).toBeUndefined();
             expect(newMock.mockConstructor.functionWithParamsAndReturn('')).toBeUndefined();
         });
+
+        it(`should work with predefined function toString`, () => {
+            const mockedValue = 'mocked toString return value';
+            const toStringMock = Mock.create<SampleMockedClass, typeof SampleMockedClass>().setup(
+                setupStaticFunction('toString', () => mockedValue),
+            );
+
+            expect(toStringMock.mockConstructor.toString()).toEqual(mockedValue);
+        });
     });
 });
 
@@ -1456,6 +1465,10 @@ class SampleMockedClass {
 
     constructor(_paramsOne: {}, _paramTwo: Date) {}
 
+    public static toString(): string {
+        return 'original toString';
+    }
+
     public static functionWithNoParamsAndNoReturn(): void {}
 
     public functionWithNoParamsAndNoReturn(): void {}

diff --git a/spec/mock/mock.spec.ts b/spec/mock/mock.spec.ts
@@ -1653,6 +1653,13 @@ describe('mock', () => {
             expect(newMock.functionWithParamsAndNoReturn('', 123, true)).toBeUndefined();
             expect(newMock.functionWithParamsAndReturn('')).toBeUndefined();
         });
+
+        it(`should work with predefined function toString`, () => {
+            const mockedValue = 'mocked toString return value';
+            const toStringMock = Mock.create<Buffer>().setup(setupFunction('toString', () => mockedValue));
+
+            expect(toStringMock.mock.toString()).toEqual(mockedValue);
+        });
     });
 
     describe('parameter comparison', () => {