fix: diff for toBeNaN/toBeUndefined/toBeNull

packages/expect/src/jest-expect.ts

@@ -376,13 +376,34 @@ export const JestChaiExpect: ChaiPlugin = (chai, utils) => {
     )
   })
   def('toBeNaN', function () {
-    return this.be.NaN
+    const obj = utils.flag(this, 'object')
+    this.assert(
+      Number.isNaN(obj),
+      'expected #{this} to be NaN',
+      'expected #{this} not to be NaN',
+      NaN,
+      obj,
+    )
   })
   def('toBeUndefined', function () {
-    return this.be.undefined
+    const obj = utils.flag(this, 'object')
+    this.assert(
+      undefined === obj,
+      'expected #{this} to be undefined',
+      'expected #{this} not to be undefined',
+      undefined,
+      obj,
+    )
   })
   def('toBeNull', function () {
-    return this.be.null
+    const obj = utils.flag(this, 'object')
+    this.assert(
+      null === obj,
+      'expected #{this} to be null',
+      'expected #{this} not to be null',
+      null,
+      obj,
+    )
   })
   def('toBeDefined', function () {
     const obj = utils.flag(this, 'object')

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

@@ -327,17 +327,68 @@ undefined",
 exports[`diff 2`] = `
 {
   "actual": "Object {
-  "k": "v",
+  "hello": "world",
 }",
   "diff": "- Expected: 
 false
 
 + Received: 
 Object {
-  "k": "v",
+  "hello": "world",
 }",
   "expected": "false",
-  "message": "expected { k: 'v' } to be falsy",
+  "message": "expected { hello: 'world' } to be falsy",
+}
+`;
+
+exports[`diff 3`] = `
+{
+  "actual": "Object {
+  "hello": "world",
+}",
+  "diff": "- Expected: 
+NaN
+
++ Received: 
+Object {
+  "hello": "world",
+}",
+  "expected": "NaN",
+  "message": "expected { hello: 'world' } to be NaN",
+}
+`;
+
+exports[`diff 4`] = `
+{
+  "actual": "Object {
+  "hello": "world",
+}",
+  "diff": "- Expected: 
+undefined
+
++ Received: 
+Object {
+  "hello": "world",
+}",
+  "expected": "undefined",
+  "message": "expected { hello: 'world' } to be undefined",
+}
+`;
+
+exports[`diff 5`] = `
+{
+  "actual": "Object {
+  "hello": "world",
+}",
+  "diff": "- Expected: 
+null
+
++ Received: 
+Object {
+  "hello": "world",
+}",
+  "expected": "null",
+  "message": "expected { hello: 'world' } to be null",
 }
 `;
 

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

@@ -1357,5 +1357,8 @@ it('timeout', () => new Promise(resolve => setTimeout(resolve, 500)))
 
 it('diff', () => {
   snapshotError(() => expect(undefined).toBeTruthy())
-  snapshotError(() => expect({ k: 'v' }).toBeFalsy())
+  snapshotError(() => expect({ hello: 'world' }).toBeFalsy())
+  snapshotError(() => expect({ hello: 'world' }).toBeNaN())
+  snapshotError(() => expect({ hello: 'world' }).toBeUndefined())
+  snapshotError(() => expect({ hello: 'world' }).toBeNull())
 })