oxc-project/oxc · warning

`{prefix}.hasAssertions` expects no arguments.

Error message

`{prefix}.hasAssertions` expects no arguments.

What it means

From the oxlint `prefer-expect-assertions` rule family (these helpers are shared/public in prefer_expect_assertions.rs): `expect.hasAssertions()` verifies that at least one assertion ran during the test and takes no arguments by design. Passing any argument is a misuse the linter reports immediately, because the argument is silently ignored at runtime.

Source

Thrown at crates/oxc_linter/src/rules/shared/jest_vitest/prefer_expect_assertions.rs:168

test('callback test', () => {
  expect.assertions(1);
  fetchData((data) => {
    expect(data).toBe('peanut butter');
  });
});
```
"#;

fn expect_shadowed_by_parameter(span: Span) -> OxcDiagnostic {
    OxcDiagnostic::warn(
        "`expect` is shadowed by a callback parameter and cannot be used for assertions.",
    )
    .with_help("Rename the parameter to avoid shadowing the global `expect`.")
    .with_label(span)
}

pub fn has_assertions_takes_no_arguments(span: Span, prefix: &str) -> OxcDiagnostic {
    OxcDiagnostic::warn(format!("`{prefix}.hasAssertions` expects no arguments."))
        .with_help(format!("Remove the arguments from `{prefix}.hasAssertions()`."))
        .with_label(span)
}

fn assertions_requires_one_argument(span: Span, prefix: &str) -> OxcDiagnostic {
    OxcDiagnostic::warn(format!("`{prefix}.assertions` expects a single argument of type number."))
        .with_help(format!("Pass a single numeric argument to `{prefix}.assertions()`."))
        .with_label(span)
}

fn assertions_requires_number_argument(span: Span) -> OxcDiagnostic {
    OxcDiagnostic::warn("This argument should be a number.")
        .with_help("Replace this argument with a numeric literal.")
        .with_label(span)
}

pub fn resolve_expect_local_name(ctx: &LintContext<'_>, sources: &[&str]) -> CompactStr {
    for entry in &ctx.module_record().import_entries {

View on GitHub (pinned to e1e7af627c)

Solutions

1. Delete the argument: use `expect.hasAssertions()`.
2. If you actually meant to require a specific count, use `expect.assertions(n)` with a single numeric literal instead.

Example fix

// before
it('syncs', () => {
  expect.hasAssertions(2);
  doSync();
  expect(synced).toBe(true);
});

// after
it('syncs', () => {
  expect.hasAssertions();
  doSync();
  expect(synced).toBe(true);
});

// .oxlintrc.json
{ "rules": { "jest/prefer-expect-assertions": "error" } }

npx oxlint tests/

When it happens

Trigger: A member call on the resolved expect prefix whose member name is `hasAssertions` and whose argument list is non-empty: `expect.hasAssertions(1)`, `expect.hasAssertions('one')`, or the same via a file-level imported alias (e.g. `myExpect.hasAssertions(x)`).

Common situations: Copy-paste from `expect.assertions(2)` where the developer changed the member name but left the count; assuming hasAssertions means 'require N assertions'; autocomplete inserting the wrong member with existing parens content.

Related errors

• `{prefix}.assertions` expects a single argument of type numb
• This argument should be a number.
• `expect` must be inside of a test block.
• Suggest using `toBeCalledWith()` or `toHaveBeenCalledWith()`
• Suggest using the built-in equality matchers.

AI-assisted analysis of oxc-project/oxc@e1e7af627c (2026-08-20). Data as JSON: /api/errors/1eaeb5e881072b82. Report an issue: GitHub.