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no-duplicate-test-case

Report repeated literal rows in framework each tables and Vitest for tables.

duplicateCase Rule source Tests Catalog JSON

Why

Identical rows repeat the same inputs and expected values without exposing a distinct case. Accidental duplicates consume test time and hide a missing boundary vector.

Fix

Remove the accidental duplicate or replace it with the intended distinct boundary. Preserve intentional repeated or stateful scenarios with a local explanation; do not delete their coverage automatically.

Examples

Before — flagged A copied row misses the intended boundary

src/format.test.ts

import { it } from "vitest";
it.each([
  [0, "0ms"],
  [0, "0ms"],
])("%s", (input, expected) => {
  expect(format(input)).toBe(expected);
});

After — preferred Distinct inputs have independent rows

src/format.test.ts

import { it } from "vitest";
it.each([
  [0, "0ms"],
  [1, "1ms"],
])("%s", (input, expected) => {
  expect(format(input)).toBe(expected);
});

Before — flagged Vitest for tables retain the same case identity

src/format.test.ts

import { test } from "vitest";
test.for([
  { input: 0, expected: "0ms" },
  { input: 0, expected: "0ms" },
])("$input", ({ input, expected }) => {
  expect(format(input)).toBe(expected);
});

After — preferred Vitest for tables preserve distinct boundaries

src/format.test.ts

import { test } from "vitest";
test.for([
  { input: 0, expected: "0ms" },
  { input: 1, expected: "1ms" },
])("$input", ({ input, expected }) => {
  expect(format(input)).toBe(expected);
});

Before — flagged Fixture reuse preserves the literal case check

src/format.test.ts

import { test as base } from "vitest";
const test = base.extend({ locale: "en" });
test.for([1, 1])("formats %s", (value, { locale }) => {
  expect(format(value, locale)).toBe("1");
});

After — preferred Fixture reuse preserves distinct independent cases

src/format.test.ts

import { test as base } from "vitest";
const test = base.extend({ locale: "en" });
test.for([1, 2])("formats %s", (value, { locale }) => {
  expect(format(value, locale)).toBe(String(value));
});