include custom mock names in error messages (#6199)

* add tests for including custom mock names in error messages

* add current behaviour in snapshots

* include custom mock name in toBeCalled matcher

* include custom mock name in toReturn matcher

* include custom mock name in toBeCalledTimes matcher

* include custom mock name in toReturnTimes matcher

* include custom mock name in toBeCalledWith matcher

* include custom mock name in toReturnWith matcher

* include custom mock name in lastCalledWith matcher

* include custom mock name in lastReturnedWith matcher

* include custom mock name in nthCalledWith matcher

* include custom mock name in nthReturnedWith matcher

* address linting issues

* update changelog

CHANGELOG.md

@@ -90,6 +90,8 @@
   ([#5879](https://github.com/facebook/jest/pull/5879))
 * `[jest-cli]` Improve snapshot summaries
   ([#6181](https://github.com/facebook/jest/pull/6181))
+* `[expect]` Include custom mock names in error messages
+  ([#6199](https://github.com/facebook/jest/pull/6199))
 
 ### Fixes
 

packages/expect/src/__tests__/__snapshots__/spy_matchers.test.js.snap

@@ -1,5 +1,12 @@
 // Jest Snapshot v1, https://goo.gl/fbAQLP
 
+exports[`lastCalledWith includes the custom mock name in the error message 1`] = `
+"<dim>expect(</><red>named-mock</><dim>).not.lastCalledWith(</><green>expected</><dim>)</>
+
+Expected mock function \\"named-mock\\" to not have been last called with:
+  <green>[\\"foo\\", \\"bar\\"]</>"
+`;
+
 exports[`lastCalledWith works only on spies or jest.fn 1`] = `
 "<dim>expect(</><red>jest.fn()</><dim>)[.not].lastCalledWith(</><dim>)</>
 
@@ -118,6 +125,14 @@ Expected mock function to have been last called with:
   Did not expect argument 2 but it was called with <red>undefined</>."
 `;
 
+exports[`lastReturnedWith includes the custom mock name in the error message 1`] = `
+"<dim>expect(</><red>named-mock</><dim>).lastReturnedWith(</><green>expected</><dim>)</>
+
+Expected mock function \\"named-mock\\" to have last returned:
+  <green>\\"foo\\"</>
+But it did <red>not return</>"
+`;
+
 exports[`lastReturnedWith works only on spies or jest.fn 1`] = `
 "<dim>expect(</><red>jest.fn()</><dim>)[.not].lastReturnedWith(</><dim>)</>
 
@@ -206,6 +221,13 @@ But it last returned:
   <red>\\"foo\\"</>"
 `;
 
+exports[`nthCalledWith includes the custom mock name in the error message 1`] = `
+"<dim>expect(</><red>named-mock</><dim>).not.nthCalledWith(</><green>expected</><dim>)</>
+
+Expected mock function \\"named-mock\\" first call to not have been called with:
+  <green>[\\"foo\\", \\"bar\\"]</>"
+`;
+
 exports[`nthCalledWith should reject non integer nth value 1`] = `"nth value <red>0.1</> must be a positive integer greater than <green>0</>"`;
 
 exports[`nthCalledWith should reject nth value smaller than 1 1`] = `"nth value <red>0</> must be a positive integer greater than <green>0</>"`;
@@ -333,6 +355,14 @@ Expected mock function first call to have been called with:
   Did not expect argument 2 but it was called with <red>undefined</>."
 `;
 
+exports[`nthReturnedWith includes the custom mock name in the error message 1`] = `
+"<dim>expect(</><red>named-mock</><dim>).nthReturnedWith(</><green>expected</><dim>)</>
+
+Expected mock function \\"named-mock\\" first call to have returned with:
+  <green>\\"foo\\"</>
+But it did <red>not return</>"
+`;
+
 exports[`nthReturnedWith should reject non integer nth value 1`] = `"nth value <red>0.1</> must be a positive integer greater than <green>0</>"`;
 
 exports[`nthReturnedWith should reject nth value smaller than 1 1`] = `"nth value <red>0</> must be a positive integer greater than <green>0</>"`;
@@ -474,6 +504,13 @@ Got:
   number: <green>555</>"
 `;
 
+exports[`toBeCalled includes the custom mock name in the error message 1`] = `
+"<dim>expect(</><red>named-mock</><dim>).not.toBeCalled(</><dim>)</>
+
+Expected mock function \\"named-mock\\" not to be called but it was called with:
+  <red>[]</>"
+`;
+
 exports[`toBeCalled passes when called 1`] = `
 "<dim>expect(</><red>jest.fn()</><dim>).not.toBeCalled(</><dim>)</>
 
@@ -549,6 +586,12 @@ exports[`toBeCalledTimes .not passes if function called more than expected times
 Expected mock function to have been called <green>two times</>, but it was called <red>three times</>."
 `;
 
+exports[`toBeCalledTimes includes the custom mock name in the error message 1`] = `
+"<dim>expect(</><red>named-mock</><dim>).toBeCalledTimes(</><green>2</><dim>)</>
+
+Expected mock function \\"named-mock\\" to have been called <green>two times</>, but it was called <red>one time</>."
+`;
+
 exports[`toBeCalledTimes only accepts a number argument 1`] = `
 "<dim>expect(</><red>received</><dim>)[.not].toBeCalledTimes(</><green>expected</><dim>)</>
 
@@ -611,6 +654,13 @@ Received:
   function: <red>[Function fn]</>"
 `;
 
+exports[`toBeCalledWith includes the custom mock name in the error message 1`] = `
+"<dim>expect(</><red>named-mock</><dim>).not.toBeCalledWith(</><green>expected</><dim>)</>
+
+Expected mock function \\"named-mock\\" not to have been called with:
+  <green>[\\"foo\\", \\"bar\\"]</>"
+`;
+
 exports[`toBeCalledWith works only on spies or jest.fn 1`] = `
 "<dim>expect(</><red>jest.fn()</><dim>)[.not].toBeCalledWith(</><dim>)</>
 
@@ -759,6 +809,13 @@ Got:
   number: <green>555</>"
 `;
 
+exports[`toHaveBeenCalled includes the custom mock name in the error message 1`] = `
+"<dim>expect(</><red>named-mock</><dim>).not.toHaveBeenCalled(</><dim>)</>
+
+Expected mock function \\"named-mock\\" not to be called but it was called with:
+  <red>[]</>"
+`;
+
 exports[`toHaveBeenCalled passes when called 1`] = `
 "<dim>expect(</><red>jest.fn()</><dim>).not.toHaveBeenCalled(</><dim>)</>
 
@@ -834,6 +891,12 @@ exports[`toHaveBeenCalledTimes .not passes if function called more than expected
 Expected mock function to have been called <green>two times</>, but it was called <red>three times</>."
 `;
 
+exports[`toHaveBeenCalledTimes includes the custom mock name in the error message 1`] = `
+"<dim>expect(</><red>named-mock</><dim>).toHaveBeenCalledTimes(</><green>2</><dim>)</>
+
+Expected mock function \\"named-mock\\" to have been called <green>two times</>, but it was called <red>one time</>."
+`;
+
 exports[`toHaveBeenCalledTimes only accepts a number argument 1`] = `
 "<dim>expect(</><red>received</><dim>)[.not].toHaveBeenCalledTimes(</><green>expected</><dim>)</>
 
@@ -896,6 +959,13 @@ Received:
   function: <red>[Function fn]</>"
 `;
 
+exports[`toHaveBeenCalledWith includes the custom mock name in the error message 1`] = `
+"<dim>expect(</><red>named-mock</><dim>).not.toHaveBeenCalledWith(</><green>expected</><dim>)</>
+
+Expected mock function \\"named-mock\\" not to have been called with:
+  <green>[\\"foo\\", \\"bar\\"]</>"
+`;
+
 exports[`toHaveBeenCalledWith works only on spies or jest.fn 1`] = `
 "<dim>expect(</><red>jest.fn()</><dim>)[.not].toHaveBeenCalledWith(</><dim>)</>
 
@@ -1022,6 +1092,13 @@ Expected mock function to have been called with:
   Did not expect argument 2 but it was called with <red>undefined</>."
 `;
 
+exports[`toHaveBeenLastCalledWith includes the custom mock name in the error message 1`] = `
+"<dim>expect(</><red>named-mock</><dim>).not.toHaveBeenLastCalledWith(</><green>expected</><dim>)</>
+
+Expected mock function \\"named-mock\\" to not have been last called with:
+  <green>[\\"foo\\", \\"bar\\"]</>"
+`;
+
 exports[`toHaveBeenLastCalledWith works only on spies or jest.fn 1`] = `
 "<dim>expect(</><red>jest.fn()</><dim>)[.not].toHaveBeenLastCalledWith(</><dim>)</>
 
@@ -1140,6 +1217,13 @@ Expected mock function to have been last called with:
   Did not expect argument 2 but it was called with <red>undefined</>."
 `;
 
+exports[`toHaveBeenNthCalledWith includes the custom mock name in the error message 1`] = `
+"<dim>expect(</><red>named-mock</><dim>).not.toHaveBeenNthCalledWith(</><green>expected</><dim>)</>
+
+Expected mock function \\"named-mock\\" first call to not have been called with:
+  <green>[\\"foo\\", \\"bar\\"]</>"
+`;
+
 exports[`toHaveBeenNthCalledWith should reject non integer nth value 1`] = `"nth value <red>0.1</> must be a positive integer greater than <green>0</>"`;
 
 exports[`toHaveBeenNthCalledWith should reject nth value smaller than 1 1`] = `"nth value <red>0</> must be a positive integer greater than <green>0</>"`;
@@ -1267,6 +1351,14 @@ Expected mock function first call to have been called with:
   Did not expect argument 2 but it was called with <red>undefined</>."
 `;
 
+exports[`toHaveLastReturnedWith includes the custom mock name in the error message 1`] = `
+"<dim>expect(</><red>named-mock</><dim>).toHaveLastReturnedWith(</><green>expected</><dim>)</>
+
+Expected mock function \\"named-mock\\" to have last returned:
+  <green>\\"foo\\"</>
+But it did <red>not return</>"
+`;
+
 exports[`toHaveLastReturnedWith works only on spies or jest.fn 1`] = `
 "<dim>expect(</><red>jest.fn()</><dim>)[.not].toHaveLastReturnedWith(</><dim>)</>
 
@@ -1355,6 +1447,14 @@ But it last returned:
   <red>\\"foo\\"</>"
 `;
 
+exports[`toHaveNthReturnedWith includes the custom mock name in the error message 1`] = `
+"<dim>expect(</><red>named-mock</><dim>).toHaveNthReturnedWith(</><green>expected</><dim>)</>
+
+Expected mock function \\"named-mock\\" first call to have returned with:
+  <green>\\"foo\\"</>
+But it did <red>not return</>"
+`;
+
 exports[`toHaveNthReturnedWith should reject non integer nth value 1`] = `"nth value <red>0.1</> must be a positive integer greater than <green>0</>"`;
 
 exports[`toHaveNthReturnedWith should reject nth value smaller than 1 1`] = `"nth value <red>0</> must be a positive integer greater than <green>0</>"`;
@@ -1496,6 +1596,13 @@ Got:
   number: <green>555</>"
 `;
 
+exports[`toHaveReturned includes the custom mock name in the error message 1`] = `
+"<dim>expect(</><red>named-mock</><dim>).not.toHaveReturned(</><dim>)</>
+
+Expected mock function \\"named-mock\\" not to have returned, but it returned:
+  <red>42</>"
+`;
+
 exports[`toHaveReturned passes when returned 1`] = `
 "<dim>expect(</><red>jest.fn()</><dim>).not.toHaveReturned(</><dim>)</>
 
@@ -1571,6 +1678,12 @@ exports[`toHaveReturnedTimes .not passes if function returned more than expected
 Expected mock function to have returned <green>two times</>, but it returned <red>three times</>."
 `;
 
+exports[`toHaveReturnedTimes includes the custom mock name in the error message 1`] = `
+"<dim>expect(</><red>named-mock</><dim>).toHaveReturnedTimes(</><green>1</><dim>)</>
+
+Expected mock function \\"named-mock\\" to have returned <green>one time</>, but it returned <red>two times</>."
+`;
+
 exports[`toHaveReturnedTimes only accepts a number argument 1`] = `
 "<dim>expect(</><red>received</><dim>)[.not].toHaveReturnedTimes(</><green>expected</><dim>)</>
 
@@ -1633,6 +1746,14 @@ Received:
   function: <red>[Function fn]</>"
 `;
 
+exports[`toHaveReturnedWith includes the custom mock name in the error message 1`] = `
+"<dim>expect(</><red>named-mock</><dim>).toHaveReturnedWith(</><green>expected</><dim>)</>
+
+Expected mock function \\"named-mock\\" to have returned:
+  <green>\\"foo\\"</>
+But it did <red>not return</>."
+`;
+
 exports[`toHaveReturnedWith works only on spies or jest.fn 1`] = `
 "<dim>expect(</><red>jest.fn()</><dim>)[.not].toHaveReturnedWith(</><dim>)</>
 
@@ -1762,6 +1883,13 @@ Got:
   number: <green>555</>"
 `;
 
+exports[`toReturn includes the custom mock name in the error message 1`] = `
+"<dim>expect(</><red>named-mock</><dim>).not.toReturn(</><dim>)</>
+
+Expected mock function \\"named-mock\\" not to have returned, but it returned:
+  <red>42</>"
+`;
+
 exports[`toReturn passes when returned 1`] = `
 "<dim>expect(</><red>jest.fn()</><dim>).not.toReturn(</><dim>)</>
 
@@ -1837,6 +1965,12 @@ exports[`toReturnTimes .not passes if function returned more than expected times
 Expected mock function to have returned <green>two times</>, but it returned <red>three times</>."
 `;
 
+exports[`toReturnTimes includes the custom mock name in the error message 1`] = `
+"<dim>expect(</><red>named-mock</><dim>).toReturnTimes(</><green>1</><dim>)</>
+
+Expected mock function \\"named-mock\\" to have returned <green>one time</>, but it returned <red>two times</>."
+`;
+
 exports[`toReturnTimes only accepts a number argument 1`] = `
 "<dim>expect(</><red>received</><dim>)[.not].toReturnTimes(</><green>expected</><dim>)</>
 
@@ -1899,6 +2033,14 @@ Received:
   function: <red>[Function fn]</>"
 `;
 
+exports[`toReturnWith includes the custom mock name in the error message 1`] = `
+"<dim>expect(</><red>named-mock</><dim>).toReturnWith(</><green>expected</><dim>)</>
+
+Expected mock function \\"named-mock\\" to have returned:
+  <green>\\"foo\\"</>
+But it did <red>not return</>."
+`;
+
 exports[`toReturnWith works only on spies or jest.fn 1`] = `
 "<dim>expect(</><red>jest.fn()</><dim>)[.not].toReturnWith(</><dim>)</>
 

packages/expect/src/__tests__/spy_matchers.test.js

@@ -45,6 +45,14 @@ const jestExpect = require('../');
         jestExpect(fn).not[called](555),
       ).toThrowErrorMatchingSnapshot();
     });
+
+    test(`includes the custom mock name in the error message`, () => {
+      const fn = jest.fn().mockName('named-mock');
+
+      fn();
+      jestExpect(fn)[called]();
+      expect(() => jestExpect(fn).not[called]()).toThrowErrorMatchingSnapshot();
+    });
   });
 });
 
@@ -118,6 +126,15 @@ const jestExpect = require('../');
         jestExpect(fn)[calledTimes](2),
       ).toThrowErrorMatchingSnapshot();
     });
+
+    test('includes the custom mock name in the error message', () => {
+      const fn = jest.fn().mockName('named-mock');
+      fn();
+
+      expect(() =>
+        jestExpect(fn)[calledTimes](2),
+      ).toThrowErrorMatchingSnapshot();
+    });
   });
 });
 
@@ -340,6 +357,17 @@ const jestExpect = require('../');
         }).toThrowErrorMatchingSnapshot();
       });
     }
+
+    test(`includes the custom mock name in the error message`, () => {
+      const fn = jest.fn().mockName('named-mock');
+      fn('foo', 'bar');
+
+      caller(jestExpect(fn)[calledWith], 'foo', 'bar');
+
+      expect(() =>
+        caller(jestExpect(fn).not[calledWith], 'foo', 'bar'),
+      ).toThrowErrorMatchingSnapshot();
+    });
   });
 });
 
@@ -383,6 +411,15 @@ const jestExpect = require('../');
         jestExpect(fn).not[returned](555),
       ).toThrowErrorMatchingSnapshot();
     });
+
+    test(`includes the custom mock name in the error message`, () => {
+      const fn = jest.fn(() => 42).mockName('named-mock');
+      fn();
+      jestExpect(fn)[returned]();
+      expect(() =>
+        jestExpect(fn).not[returned](),
+      ).toThrowErrorMatchingSnapshot();
+    });
   });
 });
 
@@ -456,6 +493,18 @@ const jestExpect = require('../');
         jestExpect(fn)[returnedTimes](2),
       ).toThrowErrorMatchingSnapshot();
     });
+
+    test('includes the custom mock name in the error message', () => {
+      const fn = jest.fn(() => 42).mockName('named-mock');
+      fn();
+      fn();
+
+      jestExpect(fn)[returnedTimes](2);
+
+      expect(() =>
+        jestExpect(fn)[returnedTimes](1),
+      ).toThrowErrorMatchingSnapshot();
+    });
   });
 });
 
@@ -674,5 +723,14 @@ const jestExpect = require('../');
         }).toThrowErrorMatchingSnapshot();
       });
     }
+
+    test(`includes the custom mock name in the error message`, () => {
+      const fn = jest.fn().mockName('named-mock');
+      caller(jestExpect(fn).not[returnedWith], 'foo');
+
+      expect(() =>
+        caller(jestExpect(fn)[returnedWith], 'foo'),
+      ).toThrowErrorMatchingSnapshot();
+    });
   });
 });