# 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.