Skip to main content

no-vacuous-string-assertions

Disallow string assertions with expected values that match anything.

Rule detailsโ€‹

Assertions such as expect(text).toContain("") and expect(text).toMatch(/.*/) look like string coverage, but they keep passing for every string value. They do not prove that the code rendered the expected label, token, error message, or format.

Incorrectโ€‹

it("renders content", () => {
    expect(renderedText()).toContain("");
});
it("renders content", () => {
    expect(renderedText()).toMatch(/.*/);
});
it("renders content", () => {
    expect(renderedText()).toEqual(expect.stringContaining(""));
});

Correctโ€‹

it("renders content", () => {
    expect(renderedText()).toContain("Saved");
});
it("renders content", () => {
    expect(renderedText()).toMatch(/^Saved \d+ items$/);
});

What this rule reportsโ€‹

This rule reports executable it(...) and test(...) callbacks that use:

  • toContain("")
  • toMatch(/.*/)
  • toMatch(/^.*$/)
  • expect.stringContaining("") as the direct expected assertion value

The rule intentionally does not evaluate computed strings or regular expressions. Project-specific constants may encode meaningful expectations.

Optionsโ€‹

This rule has no options.

When not to use itโ€‹

Disable this rule only for tests that intentionally document matcher semantics. Product tests should assert the specific text or format produced by the code under test.

Rule catalog ID: R022