fix(expect): implement chai inspect for AsymmetricMatcher

packages/expect/src/jest-asymmetric-matchers.ts

@@ -41,6 +41,16 @@ export abstract class AsymmetricMatcher<
   abstract toString(): string
   getExpectedType?(): string
   toAsymmetricMatcher?(): string
+
+  // implement custom chai/loupe inspect for better AssertionError.message formatting
+  // https://github.com/chaijs/loupe/blob/9b8a6deabcd50adc056a64fb705896194710c5c6/src/index.ts#L29
+  [Symbol.for('chai/inspect')](options: { depth: number; truncate: number }) {
+    // minimal pretty-format with simple manual truncation
+    const result = stringify(this, options.depth, { min: true })
+    if (result.length <= options.truncate)
+      return result
+    return `${this.toString()}{…}`
+  }
 }
 
 export class StringContaining extends AsymmetricMatcher<string> {

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

@@ -0,0 +1,229 @@
+// Vitest Snapshot v1, https://vitest.dev/guide/snapshot.html
+
+exports[`asymmetric matcher error 1`] = `
+{
+  "actual": "hello",
+  "diff": null,
+  "expected": "StringContaining "xx"",
+  "message": "expected 'hello' to deeply equal StringContaining "xx"",
+}
+`;
+
+exports[`asymmetric matcher error 2`] = `
+{
+  "actual": "hello",
+  "diff": null,
+  "expected": "StringNotContaining "ll"",
+  "message": "expected 'hello' to deeply equal StringNotContaining "ll"",
+}
+`;
+
+exports[`asymmetric matcher error 3`] = `
+{
+  "actual": "Object {
+  "foo": "hello",
+}",
+  "diff": "- Expected
++ Received
+
+  Object {
+-   "foo": StringContaining "xx",
++   "foo": "hello",
+  }",
+  "expected": "Object {
+  "foo": StringContaining "xx",
+}",
+  "message": "expected { foo: 'hello' } to deeply equal { foo: StringContaining "xx" }",
+}
+`;
+
+exports[`asymmetric matcher error 4`] = `
+{
+  "actual": "Object {
+  "foo": "hello",
+}",
+  "diff": "- Expected
++ Received
+
+  Object {
+-   "foo": StringNotContaining "ll",
++   "foo": "hello",
+  }",
+  "expected": "Object {
+  "foo": StringNotContaining "ll",
+}",
+  "message": "expected { foo: 'hello' } to deeply equal { foo: StringNotContaining "ll" }",
+}
+`;
+
+exports[`asymmetric matcher error 5`] = `
+{
+  "actual": "hello",
+  "diff": "- Expected: 
+stringContainingCustom<xx>
+
++ Received: 
+"hello"",
+  "expected": "stringContainingCustom<xx>",
+  "message": "expected 'hello' to deeply equal stringContainingCustom<xx>",
+}
+`;
+
+exports[`asymmetric matcher error 6`] = `
+{
+  "actual": "hello",
+  "diff": "- Expected: 
+not.stringContainingCustom<ll>
+
++ Received: 
+"hello"",
+  "expected": "not.stringContainingCustom<ll>",
+  "message": "expected 'hello' to deeply equal not.stringContainingCustom<ll>",
+}
+`;
+
+exports[`asymmetric matcher error 7`] = `
+{
+  "actual": "Object {
+  "foo": "hello",
+}",
+  "diff": "- Expected
++ Received
+
+  Object {
+-   "foo": stringContainingCustom<xx>,
++   "foo": "hello",
+  }",
+  "expected": "Object {
+  "foo": stringContainingCustom<xx>,
+}",
+  "message": "expected { foo: 'hello' } to deeply equal { foo: stringContainingCustom<xx> }",
+}
+`;
+
+exports[`asymmetric matcher error 8`] = `
+{
+  "actual": "Object {
+  "foo": "hello",
+}",
+  "diff": "- Expected
++ Received
+
+  Object {
+-   "foo": not.stringContainingCustom<ll>,
++   "foo": "hello",
+  }",
+  "expected": "Object {
+  "foo": not.stringContainingCustom<ll>,
+}",
+  "message": "expected { foo: 'hello' } to deeply equal { foo: not.stringContainingCustom<ll> }",
+}
+`;
+
+exports[`asymmetric matcher error 9`] = `
+{
+  "actual": "undefined",
+  "diff": undefined,
+  "expected": "undefined",
+  "message": "expected "hello" to contain "xx"",
+}
+`;
+
+exports[`asymmetric matcher error 10`] = `
+{
+  "actual": "undefined",
+  "diff": undefined,
+  "expected": "undefined",
+  "message": "expected "hello" not to contain "ll"",
+}
+`;
+
+exports[`asymmetric matcher error 11`] = `
+{
+  "actual": "hello",
+  "diff": "- Expected: 
+testComplexMatcher<[object Object]>
+
++ Received: 
+"hello"",
+  "expected": "testComplexMatcher<[object Object]>",
+  "message": "expected 'hello' to deeply equal testComplexMatcher<[object Object]>",
+}
+`;
+
+exports[`asymmetric matcher error 12`] = `
+{
+  "actual": "Object {
+  "k": "v",
+  "k2": "v2",
+}",
+  "diff": "- Expected
++ Received
+
+- ObjectContaining {
++ Object {
+    "k": "v",
+-   "k3": "v3",
++   "k2": "v2",
+  }",
+  "expected": "ObjectContaining {
+  "k": "v",
+  "k3": "v3",
+}",
+  "message": "expected { k: 'v', k2: 'v2' } to deeply equal ObjectContaining {"k": "v", "k3": "v3"}",
+}
+`;
+
+exports[`asymmetric matcher error 13`] = `
+{
+  "actual": "Array [
+  "a",
+  "b",
+]",
+  "diff": "- Expected
++ Received
+
+- ArrayContaining [
++ Array [
+    "a",
+-   "c",
++   "b",
+  ]",
+  "expected": "ArrayContaining [
+  "a",
+  "c",
+]",
+  "message": "expected [ 'a', 'b' ] to deeply equal ArrayContaining ["a", "c"]",
+}
+`;
+
+exports[`asymmetric matcher error 14`] = `
+{
+  "actual": "hello",
+  "diff": null,
+  "expected": "StringMatching /xx/",
+  "message": "expected 'hello' to deeply equal StringMatching /xx/",
+}
+`;
+
+exports[`asymmetric matcher error 15`] = `
+{
+  "actual": "2.5",
+  "diff": "- Expected
++ Received
+
+- NumberCloseTo 2 (1 digit)
++ 2.5",
+  "expected": "NumberCloseTo 2 (1 digit)",
+  "message": "expected 2.5 to deeply equal NumberCloseTo 2 (1 digit)",
+}
+`;
+
+exports[`asymmetric matcher error 16`] = `
+{
+  "actual": "hello",
+  "diff": null,
+  "expected": "StringContaining "aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa"",
+  "message": "expected 'hello' to deeply equal StringContaining{…}",
+}
+`;

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

@@ -180,7 +180,7 @@ describe('jest-expect', () => {
       }).toEqual({
         sum: expect.closeTo(0.4),
       })
-    }).toThrowErrorMatchingInlineSnapshot(`[AssertionError: expected { sum: 0.30000000000000004 } to deeply equal { sum: CloseTo{ …(4) } }]`)
+    }).toThrowErrorMatchingInlineSnapshot(`[AssertionError: expected { sum: 0.30000000000000004 } to deeply equal { sum: NumberCloseTo 0.4 (2 digits) }]`)
   })
 
   it('asymmetric matchers negate', () => {
@@ -947,7 +947,7 @@ it('toHaveProperty error diff', () => {
   // non match value (with asymmetric matcher)
   expect(getError(() => expect({ name: 'foo' }).toHaveProperty('name', expect.any(Number)))).toMatchInlineSnapshot(`
     [
-      "expected { name: 'foo' } to have property "name" with value Any{ …(3) }",
+      "expected { name: 'foo' } to have property "name" with value Any<Number>",
       "- Expected:
     Any<Number>
 
@@ -959,7 +959,7 @@ it('toHaveProperty error diff', () => {
   // non match key (with asymmetric matcher)
   expect(getError(() => expect({ noName: 'foo' }).toHaveProperty('name', expect.any(Number)))).toMatchInlineSnapshot(`
     [
-      "expected { noName: 'foo' } to have property "name" with value Any{ …(3) }",
+      "expected { noName: 'foo' } to have property "name" with value Any<Number>",
       "- Expected:
     Any<Number>
 
@@ -993,4 +993,70 @@ it('toHaveProperty error diff', () => {
   `)
 })
 
+it('asymmetric matcher error', () => {
+  setupColors(getDefaultColors())
+
+  function snapshotError(f: () => unknown) {
+    try {
+      f()
+      return expect.unreachable()
+    }
+    catch (error) {
+      const e = processError(error)
+      expect({
+        message: e.message,
+        diff: e.diff,
+        expected: e.expected,
+        actual: e.actual,
+      }).toMatchSnapshot()
+    }
+  }
+
+  expect.extend({
+    stringContainingCustom(received: unknown, other: string) {
+      return {
+        pass: typeof received === 'string' && received.includes(other),
+        message: () => `expected ${this.utils.printReceived(received)} ${this.isNot ? 'not ' : ''}to contain ${this.utils.printExpected(other)}`,
+      }
+    },
+  })
+
+  // builtin: stringContaining
+  snapshotError(() => expect('hello').toEqual(expect.stringContaining('xx')))
+  snapshotError(() => expect('hello').toEqual(expect.not.stringContaining('ll')))
+  snapshotError(() => expect({ foo: 'hello' }).toEqual({ foo: expect.stringContaining('xx') }))
+  snapshotError(() => expect({ foo: 'hello' }).toEqual({ foo: expect.not.stringContaining('ll') }))
+
+  // custom
+  snapshotError(() => expect('hello').toEqual((expect as any).stringContainingCustom('xx')))
+  snapshotError(() => expect('hello').toEqual((expect as any).not.stringContainingCustom('ll')))
+  snapshotError(() => expect({ foo: 'hello' }).toEqual({ foo: (expect as any).stringContainingCustom('xx') }))
+  snapshotError(() => expect({ foo: 'hello' }).toEqual({ foo: (expect as any).not.stringContainingCustom('ll') }))
+
+  // assertion form
+  snapshotError(() => (expect('hello') as any).stringContainingCustom('xx'))
+  snapshotError(() => (expect('hello') as any).not.stringContainingCustom('ll'))
+
+  // matcher with complex argument
+  // (serialized by `String` so it becomes "testComplexMatcher<[object Object]>", which is same as jest's asymmetric matcher and pretty-format)
+  expect.extend({
+    testComplexMatcher(_received: unknown, _arg: unknown) {
+      return {
+        pass: false,
+        message: () => `NA`,
+      }
+    },
+  })
+  snapshotError(() => expect('hello').toEqual((expect as any).testComplexMatcher({ x: 'y' })))
+
+  // more builtins
+  snapshotError(() => expect({ k: 'v', k2: 'v2' }).toEqual(expect.objectContaining({ k: 'v', k3: 'v3' })))
+  snapshotError(() => expect(['a', 'b']).toEqual(expect.arrayContaining(['a', 'c'])))
+  snapshotError(() => expect('hello').toEqual(expect.stringMatching(/xx/)))
+  snapshotError(() => expect(2.5).toEqual(expect.closeTo(2, 1)))
+
+  // simple truncation if pretty-format is too long
+  snapshotError(() => expect('hello').toEqual(expect.stringContaining('a'.repeat(40))))
+})
+
 it('timeout', () => new Promise(resolve => setTimeout(resolve, 500)))