vitest/prefer-expect-assertions

📝 Enforce using expect assertions instead of callbacks.

⚠️ This rule warns in the 🌐 all config.

💡 This rule is manually fixable by editor suggestions.

Ensure every test to have either expect.assertions(<number of assertions>) OR expect.hasAssertions() as its first expression.

This will warn if a test has no assertions, or if it has assertions but they are not the first expression.

Examples

Examples of incorrect code for this rule:

test('no assertions', () => {
  // ...
})

test('assertions not first', () => {
  expect(true).toBe(true)
  // ...
})

Examples of correct code for this rule:

test('assertions first', () => {
  expect.assertions(1)
  // ...
})

test('assertions first', () => {
  expect.hasAssertions()
  // ...
})

Name	Description	Type
`onlyFunctionsWithAsyncKeyword`	Only check test functions declared with the async keyword.	Boolean
`onlyFunctionsWithExpectInCallback`	Only check test functions that contain `expect` in callbacks.	Boolean
`onlyFunctionsWithExpectInLoop`	Only check test functions that contain `expect` inside loops.	Boolean

onlyFunctionsWithAsyncKeyword (default: false)

When true, only functions with the async keyword will be checked.

when this option is enabled the following code will be considered incorrect:

test('assertions first', async () => {
  const data = await fetchData()
  expect(data).toBe('peanut butter')
})

To fix this, you'll need to add expect.assertions(1) or expect.hasAssertions() as the first expression:

test('assertions first', async () => {
  expect.assertions(1)
  const data = await fetchData()
  expect(data).toBe('peanut butter')
})

onlyFunctionsWithExpectInLoop (default: false)

When true, only functions with expect in a loop will be checked.

when this option is enabled the following code will be considered incorrect:

test('assertions first', () => {
  for (let i = 0; i < 10; i++) {
    expect(i).toBeLessThan(10)
  }
})

To fix this, you'll need to add expect.assertions(1) or expect.hasAssertions() as the first expression:

test('assertions first', () => {
  expect.hasAssertions()
  for (let i = 0; i < 10; i++) {
    expect(i).toBeLessThan(10)
  }
})

onlyFunctionsWithExpectInCallback

When true, only functions with expect in a callback will be checked.

when this option is enabled the following code will be considered incorrect:

test('assertions first', () => {
  fetchData((data) => {
    expect(data).toBe('peanut butter')
  })
})

To fix this, you'll need to add expect.assertions(1) or expect.hasAssertions() as the first expression:

test('assertions first', () => {
  expect.assertions(1)
  fetchData((data) => {
    expect(data).toBe('peanut butter')
  })
})