feat: add describe.for (#7253)

Author: hi-ogawa

docs/api/index.md

@@ -948,6 +948,11 @@ describe.todo('unimplemented suite')
 
 - **Alias:** `suite.each`
 
+::: tip
+While `describe.each` is provided for Jest compatibility,
+Vitest also has [`describe.for`](#describe-for) which simplifies argument types and aligns with [`test.for`](#test-for).
+:::
+
 Use `describe.each` if you have more than one test that depends on the same data.
 
 ```ts
@@ -998,6 +1003,37 @@ describe.each`
 You cannot use this syntax when using Vitest as [type checker](/guide/testing-types).
 :::
 
+### describe.for
+
+- **Alias:** `suite.for`
+
+The difference from `describe.each` is how array case is provided in the arguments.
+Other non array case (including template string usage) works exactly same.
+
+```ts
+// `each` spreads array case
+describe.each([
+  [1, 1, 2],
+  [1, 2, 3],
+  [2, 1, 3],
+])('add(%i, %i) -> %i', (a, b, expected) => { // [!code --]
+  test('test', () => {
+    expect(a + b).toBe(expected)
+  })
+})
+
+// `for` doesn't spread array case
+describe.for([
+  [1, 1, 2],
+  [1, 2, 3],
+  [2, 1, 3],
+])('add(%i, %i) -> %i', ([a, b, expected]) => { // [!code ++]
+  test('test', () => {
+    expect(a + b).toBe(expected)
+  })
+})
+```
+
 ## Setup and Teardown
 
 These functions allow you to hook into the life cycle of tests to avoid repeating setup and teardown code. They apply to the current context: the file if they are used at the top-level or the current suite if they are inside a `describe` block. These hooks are not called, when you are running Vitest as a type checker.

packages/runner/src/suite.ts

@@ -594,6 +594,31 @@ function createSuite() {
     }
   }
 
+  suiteFn.for = function <T>(
+    this: {
+      withContext: () => SuiteAPI
+      setContext: (key: string, value: boolean | undefined) => SuiteAPI
+    },
+    cases: ReadonlyArray<T>,
+    ...args: any[]
+  ) {
+    if (Array.isArray(cases) && args.length) {
+      cases = formatTemplateString(cases, args)
+    }
+
+    return (
+      name: string | Function,
+      optionsOrFn: ((...args: T[]) => void) | TestOptions,
+      fnOrOptions?: ((...args: T[]) => void) | number | TestOptions,
+    ) => {
+      const name_ = formatName(name)
+      const { options, handler } = parseArguments(optionsOrFn, fnOrOptions)
+      cases.forEach((item, idx) => {
+        suite(formatTitle(name_, toArray(item), idx), options, () => handler(item))
+      })
+    }
+  }
+
   suiteFn.skipIf = (condition: any) =>
     (condition ? suite.skip : suite) as SuiteAPI
   suiteFn.runIf = (condition: any) =>

packages/runner/src/types/tasks.ts

@@ -360,6 +360,11 @@ interface TestForFunction<ExtraContext> {
   >
 }
 
+interface SuiteForFunction {
+  <T>(cases: ReadonlyArray<T>): EachFunctionReturn<[T]>
+  (...args: [TemplateStringsArray, ...any]): EachFunctionReturn<any[]>
+}
+
 interface TestCollectorCallable<C = object> {
   /**
    * @deprecated Use options as the second argument instead
@@ -525,6 +530,7 @@ type ChainableSuiteAPI<ExtraContext = object> = ChainableFunction<
   SuiteCollectorCallable<ExtraContext>,
   {
     each: TestEachFunction
+    for: SuiteForFunction
   }
 >
 

test/core/test/__snapshots__/test-for-suite.test.ts.snap

@@ -0,0 +1,45 @@
+// Vitest Snapshot v1, https://vitest.dev/guide/snapshot.html
+
+exports[`add(1, 1) > test 1`] = `2`;
+
+exports[`add(1, 2) > test 1`] = `3`;
+
+exports[`add(2, 1) > test 1`] = `3`;
+
+exports[`basic case1 > test 1`] = `
+{
+  "args": [
+    "case1",
+  ],
+}
+`;
+
+exports[`basic case2 > test 1`] = `
+{
+  "args": [
+    "case2",
+  ],
+}
+`;
+
+exports[`template 'x' true > test 1`] = `
+{
+  "args": [
+    {
+      "a": "x",
+      "b": true,
+    },
+  ],
+}
+`;
+
+exports[`template 'y' false > test 1`] = `
+{
+  "args": [
+    {
+      "a": "y",
+      "b": false,
+    },
+  ],
+}
+`;

test/core/test/test-for-suite.test.ts

@@ -0,0 +1,35 @@
+import { describe, expect, expectTypeOf, test } from 'vitest'
+
+describe.for(['case1', 'case2'])(
+  'basic %s',
+  (...args) => {
+    test('test', () => {
+      expectTypeOf(args).toEqualTypeOf<[string]>()
+      expect({ args }).matchSnapshot()
+    })
+  },
+)
+
+describe.for`
+  a         | b
+  ${'x'}    | ${true}
+  ${'y'}    | ${false}
+`(
+  'template $a $b',
+  (...args) => {
+    test('test', () => {
+      expectTypeOf(args).toEqualTypeOf<any[]>()
+      expect({ args }).toMatchSnapshot()
+    })
+  },
+)
+
+describe.for([
+  [1, 1],
+  [1, 2],
+  [2, 1],
+])('add(%i, %i)', ([a, b]) => {
+  test('test', () => {
+    expect(a + b).matchSnapshot()
+  })
+})