Add matcher result tests

packages/jest-matchers/src/__tests__/matchers-test.js

@@ -55,6 +55,20 @@ describe('.toBe()', () => {
     expect(() => jestExpect(obj).toBe({}))
       .toThrowErrorMatchingSnapshot();
   });
+
+  test('assertion error matcherResult property contains matcher name, expected and actual values', () => {
+    const actual = {a: 1};
+    const expected = {a: 2};
+    try {
+      jestExpect(actual).toBe(expected);
+    } catch (error) {
+      expect(error.matcherResult).toEqual(expect.objectContaining({
+        actual,
+        expected,
+        name: 'toBe',
+      }));
+    }
+  });
 });
 
 describe('.toEqual()', () => {
@@ -101,6 +115,20 @@ describe('.toEqual()', () => {
         .toThrowErrorMatchingSnapshot();
     });
   });
+
+  test('assertion error matcherResult property contains matcher name, expected and actual values', () => {
+    const actual = {a: 1};
+    const expected = {a: 2};
+    try {
+      jestExpect(actual).toEqual(expected);
+    } catch (error) {
+      expect(error.matcherResult).toEqual(expect.objectContaining({
+        actual,
+        expected,
+        name: 'toEqual',
+      }));
+    }
+  });
 });
 
 describe('.toBeInstanceOf()', () => {

packages/jest-snapshot/src/__tests__/matcher-test.js

@@ -0,0 +1,27 @@
+/**
+ * Copyright (c) 2016-present, Facebook, Inc. All rights reserved.
+ *
+ * This source code is licensed under the BSD-style license found in the
+ * LICENSE file in the root directory of this source tree. An additional grant
+ * of patent rights can be found in the PATENTS file in the same directory.
+ *
+ */
+'use strict';
+
+const {toMatchSnapshot} = require('../');
+
+it(`matcher returns matcher name, expected and actual values`, () => {
+  const actual = 'a';
+  const expected = 'b';
+  const matcher = toMatchSnapshot.bind({
+    snapshotState: {match: (testName, received) => ({actual, expected})},
+  });
+
+  const matcherResult = matcher({a: 1});
+
+  expect(matcherResult).toEqual(expect.objectContaining({
+    actual,
+    expected,
+    name: 'toMatchSnapshot',
+  }));
+});