Add support for nested matchers on .not/.rejects/.resolves

mattphillips · Aug 7, 2018 · 0fd13a0 · 0fd13a0
1 parent 264a3c7
commit 0fd13a0
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Showing 3 changed files with 71 additions and 17 deletions.
diff --git a/src/__snapshots__/withMessage.test.js.snap b/src/__snapshots__/withMessage.test.js.snap
@@ -6,3 +6,10 @@ exports[`withMessage() throws error with custom message when matcher fails 1`] =
 
 expected ACTUAL to be 1"
 `;
+
+exports[`withMessage() throws error with custom message when not matcher fails 1`] = `
+"Custom message:
+  should fail
+
+expected ACTUAL to not be ACTUAL"
+`;
diff --git a/src/withMessage.js b/src/withMessage.js
@@ -10,23 +10,31 @@ class JestAssertionError extends Error {
 }
 
 const wrapMatchers = (matchers, customMessage) => {
-  return Object.keys(matchers).reduce((acc, key) => {
-    const matcher = matchers[key];
-    const newMatcher = (...args) => {
-      try {
-        matcher(...args);
-      } catch (error) {
-        if (typeof customMessage !== 'string' || customMessage.length < 1 || !error.matcherResult) {
-          throw error;
-        }
+  return Object.keys(matchers).reduce((acc, name) => {
+    const matcher = matchers[name];
+
+    if (typeof matcher === 'function') {
+      const newMatcher = (...args) => {
+        try {
+          matcher(...args);
+        } catch (error) {
+          if (typeof customMessage !== 'string' || customMessage.length < 1 || !error.matcherResult) {
+            throw error;
+          }
+
+          const { matcherResult } = error;
+          const message = () => 'Custom message:\n  ' + customMessage + '\n\n' + matcherResult.message();
 
-        const { matcherResult } = error;
-        const message = () => 'Custom message:\n  ' + customMessage + '\n\n' + matcherResult.message();
+          throw new JestAssertionError(Object.assign({}, matcherResult, { message }), newMatcher);
+        }
+      };
+      return { ...acc, [name]: newMatcher };
+    }
 
-        throw new JestAssertionError(Object.assign({}, matcherResult, { message }), newMatcher);
-      }
+    return {
+      ...acc,
+      [name]: wrapMatchers(matcher, customMessage) // recurse on .not/.resolves/.rejects
     };
-    return Object.assign({}, acc, { [key]: newMatcher });
   }, {});
 };
 

diff --git a/src/withMessage.test.js b/src/withMessage.test.js
@@ -10,18 +10,28 @@ describe('withMessage()', () => {
     expectMock.extend = 'extend';
 
     const newExpect = withMessage(expectMock);
-    newExpect(ACTUAL, 'should fail').toBe(1);
+    newExpect(ACTUAL, 'should fail').toBe(ACTUAL);
     expect(newExpect.extend).toBe('extend');
     expect(expectMock).toHaveBeenCalledWith(ACTUAL);
-    expect(toBeMock).toHaveBeenCalledWith(1);
+    expect(toBeMock).toHaveBeenCalledWith(ACTUAL);
   });
 
   test('does not throw when matcher passes', () => {
     expect.assertions(2);
     const toBeMock = jest.fn();
     const expectMock = jest.fn(() => ({ toBe: toBeMock }));
 
-    withMessage(expectMock)(ACTUAL, 'should fail').toBe(1);
+    withMessage(expectMock)(ACTUAL, 'should fail').toBe(ACTUAL);
+    expect(expectMock).toHaveBeenCalledWith(ACTUAL);
+    expect(toBeMock).toHaveBeenCalledWith(ACTUAL);
+  });
+
+  test('does not throw when matcher passes when using not', () => {
+    expect.assertions(2);
+    const toBeMock = jest.fn();
+    const expectMock = jest.fn(() => ({ not: { toBe: toBeMock } }));
+
+    withMessage(expectMock)(ACTUAL, 'should fail').not.toBe(1);
     expect(expectMock).toHaveBeenCalledWith(ACTUAL);
     expect(toBeMock).toHaveBeenCalledWith(1);
   });
@@ -88,4 +98,33 @@ describe('withMessage()', () => {
       expect(toBeMock).toHaveBeenCalledWith(1);
     }
   });
+
+  test('throws error with custom message when not matcher fails', () => {
+    expect.assertions(4);
+    const originalError = new Error('Boo');
+    originalError.matcherResult = {
+      actual: ACTUAL,
+      expected: 1,
+      message: () => 'expected ACTUAL to not be ACTUAL',
+      pass: false
+    };
+
+    const toBeMock = jest.fn(() => {
+      throw originalError;
+    });
+    const expectMock = jest.fn(() => ({ not: { toBe: toBeMock } }));
+
+    try {
+      withMessage(expectMock)(ACTUAL, 'should fail').not.toBe(ACTUAL);
+    } catch (e) {
+      expect(e.matcherResult).toMatchObject({
+        actual: ACTUAL,
+        expected: 1,
+        pass: false
+      });
+      expect(e.message).toMatchSnapshot();
+      expect(expectMock).toHaveBeenCalledWith(ACTUAL);
+      expect(toBeMock).toHaveBeenCalledWith(ACTUAL);
+    }
+  });
 });