Disallow using expect outside of it or test blocks (no-standalone-expect)

Prevents expect statements outside of a test or it block. An expect within a helper function (but outside of a test or it block) will not trigger this rule.

Rule Details

This rule aims to eliminate expect statements that will not be executed. An expect inside of a describe block but outside of a test or it block or outside a describe will not execute and therefore will trigger this rule. It is viable, however, to have an expect in a helper function that is called from within a test or it block so expect statements in a function will not trigger this rule.

Statements like expect.hasAssertions() will NOT trigger this rule since these calls will execute if they are not in a test block.

Examples of incorrect code for this rule:

```js // in describe describe(‘a test’, () => { expect(1).toBe(1); });

// below other tests describe(‘a test’, () => { it(‘an it’, () => { expect(1).toBe(1); });

expect(1).toBe(1); }); ```

Examples of correct code for this rule:

```js // in it block describe(‘a test’, () => { it(‘an it’, () => { expect(1).toBe(1); }); });

// in helper function describe(‘a test’, () => { const helper = () => { expect(1).toBe(1); };

it(‘an it’, () => { helper(); }); });

describe(‘a test’, () => { expect.hasAssertions(1); }); ```

*Note that this rule will not trigger if the helper function is never used even thought the expect will not execute. Rely on a rule like no-unused-vars for this case.

Options

additionalTestBlockFunctions

This array can be used to specify the names of functions that should also be treated as test blocks:

json { "rules": { "jest/no-standalone-expect": [ "error", { "additionalTestBlockFunctions": ["each.test"] } ] } }

The following is correct when using the above configuration:

js each([ [1, 1, 2], [1, 2, 3], [2, 1, 3], ]).test('returns the result of adding %d to %d', (a, b, expected) => { expect(a + b).toBe(expected); });

When Not To Use It

Don’t use this rule on non-jest test files.