no-standalone-expect.md

No standalone expect in a describe block (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 of 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:

// 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:

// 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.

When Not To Use It

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