test: update test case, types and documentation

vitest-dev · Oct 6, 2023 · 4f765b0 · 4f765b0
1 parent bbd68c9
commit 4f765b0
Show file tree

Hide file tree

Showing 3 changed files with 32 additions and 7 deletions.
diff --git a/docs/api/expect.md b/docs/api/expect.md
@@ -1210,6 +1210,29 @@ If the value in the error message is too truncated, you can increase [chaiConfig
   })
   ```
 
+## expect.closeTo
+
+- **Type:** `(expected: any, precision?: number) => any`
+- **Version:** Since Vitest 1.0.0
+
+`expect.closeTo` is useful when comparing floating point numbers in object properties or array item. If you need to compare a number, please use `.toBeCloseTo` instead.
+
+The optional `numDigits` argument limits the number of digits to check **after** the decimal point. For the default value `2`, the test criterion is `Math.abs(expected - received) < 0.005 (that is, 10 ** -2 / 2)`.
+
+For example, this test passes with a precision of 5 digits:
+
+```js
+test('compare float in object properties', () => {
+  expect({
+    title: '0.1 + 0.2',
+    sum: 0.1 + 0.2,
+  }).toEqual({
+    title: '0.1 + 0.2',
+    sum: expect.closeTo(0.3, 5),
+  })
+})
+```
+
 ## expect.arrayContaining
 
 - **Type:** `<T>(expected: T[]) => any`

diff --git a/packages/expect/src/types.ts b/packages/expect/src/types.ts
@@ -94,7 +94,7 @@ export interface AsymmetricMatchersContaining {
   objectContaining<T = any>(expected: T): any
   arrayContaining<T = unknown>(expected: Array<T>): any
   stringMatching(expected: string | RegExp): any
-  closeTo(expected: any, precision?: number): any
+  closeTo(expected: number, precision?: number): any
 }
 
 export interface JestAssertion<T = any> extends jest.Matchers<void, T> {

diff --git a/test/core/test/jest-expect.test.ts b/test/core/test/jest-expect.test.ts
@@ -144,29 +144,31 @@ describe('jest-expect', () => {
     expect('Mohammad').toEqual(expect.stringMatching(/Moh/))
     expect('Mohammad').not.toEqual(expect.stringMatching(/jack/))
     expect({
-      title: '0.1 + 0.2',
       sum: 0.1 + 0.2,
     }).toEqual({
-      title: '0.1 + 0.2',
       sum: expect.closeTo(0.3, 5),
     })
 
     expect({
-      title: '0.1 + 0.2',
       sum: 0.1 + 0.2,
     }).not.toEqual({
-      title: '0.1 + 0.2',
       sum: expect.closeTo(0.4, 5),
     })
 
     expect({
-      title: '0.1 + 0.2',
       sum: 0.1 + 0.2,
     }).toEqual({
-      title: '0.1 + 0.2',
       sum: expect.not.closeTo(0.4, 5),
     })
 
+    expect(() => {
+      expect({
+        sum: 0.1 + 0.2,
+      }).toEqual({
+        sum: expect.closeTo(0.4),
+      })
+    }).toThrowErrorMatchingInlineSnapshot(`"expected { sum: 0.30000000000000004 } to deeply equal { sum: CloseTo{ …(4) } }"`)
+
     // TODO: support set
     // expect(new Set(['bar'])).not.toEqual(new Set([expect.stringContaining('zoo')]))
   })