fix(expect): improve toThrow(asymmetricMatcher) failure message (#5000

)

packages/expect/src/jest-expect.ts

@@ -581,7 +581,6 @@ export const JestChaiExpect: ChaiPlugin = (chai, utils) => {
         `expected error not to be instance of ${name}`,
         expected,
         thrown,
-        false,
       )
     }
 
@@ -601,9 +600,8 @@ export const JestChaiExpect: ChaiPlugin = (chai, utils) => {
         thrown && matcher.asymmetricMatch(thrown),
         'expected error to match asymmetric matcher',
         'expected error not to match asymmetric matcher',
-        matcher.toString(),
+        matcher,
         thrown,
-        false,
       )
     }
 

test/core/test/__snapshots__/jest-expect.test.ts.snap

@@ -227,3 +227,86 @@ exports[`asymmetric matcher error 16`] = `
   "message": "expected 'hello' to deeply equal StringContaining{…}",
 }
 `;
+
+exports[`asymmetric matcher error 17`] = `
+{
+  "actual": "hello",
+  "diff": null,
+  "expected": "StringContaining "xx"",
+  "message": "expected error to match asymmetric matcher",
+}
+`;
+
+exports[`asymmetric matcher error 18`] = `
+{
+  "actual": "hello",
+  "diff": "- Expected: 
+stringContainingCustom<xx>
+
++ Received: 
+"hello"",
+  "expected": "stringContainingCustom<xx>",
+  "message": "expected error to match asymmetric matcher",
+}
+`;
+
+exports[`asymmetric matcher error 19`] = `
+{
+  "actual": "hello",
+  "diff": null,
+  "expected": "StringContaining "ll"",
+  "message": "expected error not to match asymmetric matcher",
+}
+`;
+
+exports[`asymmetric matcher error 20`] = `
+{
+  "actual": "hello",
+  "diff": "- Expected: 
+stringContainingCustom<ll>
+
++ Received: 
+"hello"",
+  "expected": "stringContainingCustom<ll>",
+  "message": "expected error not to match asymmetric matcher",
+}
+`;
+
+exports[`asymmetric matcher error 21`] = `
+{
+  "actual": "[Error: hello]",
+  "diff": "- Expected: 
+StringContaining "ll"
+
++ Received: 
+[Error: hello]",
+  "expected": "StringContaining "ll"",
+  "message": "expected error to match asymmetric matcher",
+}
+`;
+
+exports[`asymmetric matcher error 22`] = `
+{
+  "actual": "[Error: hello]",
+  "diff": "- Expected: 
+stringContainingCustom<ll>
+
++ Received: 
+[Error: hello]",
+  "expected": "stringContainingCustom<ll>",
+  "message": "expected error to match asymmetric matcher",
+}
+`;
+
+exports[`asymmetric matcher error 23`] = `
+{
+  "actual": "[Error: hello]",
+  "diff": "- Expected: 
+[Function MyError1]
+
++ Received: 
+[Error: hello]",
+  "expected": "[Function MyError1]",
+  "message": "expected error to be instance of MyError1",
+}
+`;

test/core/test/jest-expect.test.ts

@@ -1057,6 +1057,31 @@ it('asymmetric matcher error', () => {
 
   // simple truncation if pretty-format is too long
   snapshotError(() => expect('hello').toEqual(expect.stringContaining('a'.repeat(40))))
+
+  // error message on `toThrow(asymmetricMatcher)` failure
+  function throwError() {
+    // eslint-disable-next-line no-throw-literal
+    throw 'hello'
+  }
+  snapshotError(() => expect(throwError).toThrow(expect.stringContaining('xx')))
+  snapshotError(() => expect(throwError).toThrow((expect as any).stringContainingCustom('xx')))
+  snapshotError(() => expect(throwError).not.toThrow(expect.stringContaining('ll')))
+  snapshotError(() => expect(throwError).not.toThrow((expect as any).stringContainingCustom('ll')))
+
+  snapshotError(() => expect(() => {
+    throw new Error('hello')
+  }).toThrow(expect.stringContaining('ll')))
+  snapshotError(() => expect(() => {
+    throw new Error('hello')
+  }).toThrow((expect as any).stringContainingCustom('ll')))
+
+  // error constructor
+  class MyError1 extends Error {}
+  class MyError2 extends Error {}
+
+  snapshotError(() => expect(() => {
+    throw new MyError2('hello')
+  }).toThrow(MyError1))
 })
 
 it('timeout', () => new Promise(resolve => setTimeout(resolve, 500)))