no-loop-static-title

📝 Disallow a static test or suite title inside a loop.

💼 This rule is enabled in the following configs: ✅ recommended, ☑️ unopinionated.

Generating tests in a loop is a common pattern, but if the title is a static string, every iteration registers a test with the same title. That makes failures ambiguous (you cannot tell which iteration failed) and defeats the purpose of looping. The fix is to include the loop variable in the title.

This rule reports a test/it/describe/suite call whose title resolves to a constant string when it appears directly inside a loop (for, for…of, for…in, while, do…while) or inside a map/forEach/flatMap callback. A title that interpolates the loop variable is not static, so it is left alone. A static title nested under a dynamically-named describe is also fine, since the parent suite makes it unique.

Unlike no-identical-title, which compares distinct call sites, this rule catches duplicates produced by a single call site that runs many times.

Examples

import {test} from 'node:test';

// ❌
for (const input of inputs) {
	test('handles input', () => {
		assert.ok(process(input));
	});
}

// ✅
for (const input of inputs) {
	test(`handles ${input}`, () => {
		assert.ok(process(input));
	});
}