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TEST002-no-asserts — Test File With No Assertions

Dimension: TestSmell Default severity: Medium Languages: All Last reviewed: 2026-05-05

What it detects​

Flags test files that contain at least one test function but no recognised assertion token anywhere in the source text.

A file is considered a "test file" when the [SemanticIndex] contains at least one FunctionLike entry with is_test = true. If the raw source text of such a file matches none of the assertion patterns listed below, one finding spanning the whole file is emitted.

Recognised assertion tokens​

The analyzer uses a single compiled regex with the following alternatives:

TokenLanguage / Framework
assertPython built-in, generic
assert_eq!Rust standard macro
assert_ne!Rust standard macro
panic!Rust macro (counts as assertion of unreachability)
assertEqualPython unittest.TestCase
assertTruePython unittest.TestCase
assertFalsePython unittest.TestCase
assertInPython unittest.TestCase
assertIsPython unittest.TestCase
expectJest, Chai, Vitest, generic
should.Chai should-style
chai.expectChai explicit-import style
sinon.assertSinon.JS spy/stub assertions
jest.Jest utility assertions (jest.fn, jest.spyOn, etc.)

Why it matters​

A test that never asserts anything will always pass regardless of the code under test. These "vacuous" tests give a false sense of coverage and provide no regression protection.

Configuration​

No configuration knobs. The assertion pattern set is fixed.

Example — flagged​

Python:

def test_thing():
    # No assertion → TEST002 will fire.
    x = 1
    _ = x + 1

Rust:

#[test]
fn test_thing() {
    // No assertion → TEST002 will fire.
    let _ = 1;
}

JavaScript:

function test_thing(): void {
    // No assertion → TEST002 will fire.
    const x = 1;
}

Example — not flagged​

Python:

def test_thing():
    x = 1
    assert x == 1   # ← assertion found; file is clean

Rust:

#[test]
fn test_thing() {
    let x = 1;
    assert_eq!(x, 1);  // ← assertion found; file is clean
}

Fix guidance​

  • Add at least one assert / expect / assertEqual / assert_eq! call (or equivalent for your test framework) to every test function.
  • Consider using a linter rule (e.g. pytest's --strict-markers, eslint-plugin-jest/no-standalone-expect) to enforce assertions automatically.

Implementation​

References​