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duplicate-test-body

Disallow substantial sibling tests with the same body shape; express their differing inputs as a parameterized case table.

duplicateTestBody Rule source Tests Catalog JSON

Why

Copy-pasted test bodies hide the cases that differ and allow equivalent assertions to drift independently.

Fix

Consider a case table with one named test or subtest per case; preserve setup lifetime, test modifiers, and each case's assertions rather than deleting coverage.

Examples

Before — flagged Sibling tests repeat the same body

src/user.test.ts

test("accepts a", () => {
  const value = "a";
  const result = parse(value);
  expect(result.ok).toBe(true);
  expect(result.value).toBe(value);
});
test("accepts b", () => {
  const value = "b";
  const result = parse(value);
  expect(result.ok).toBe(true);
  expect(result.value).toBe(value);
});

After — preferred A case table shares one test body

src/user.test.ts

test.each(["a", "b"])("accepts %s", (value) => {
  const result = parse(value);
  expect(result.ok).toBe(true);
  expect(result.value).toBe(value);
});