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no-broad-object-key-count-assertions

Disallow object key-count assertions that only prove an object is non-empty.

Rule detailsโ€‹

Object.keys(value).length > 0 proves only that an object has at least one own enumerable key. It does not prove that the object has the expected shape, required keys, or expected values. These assertions are especially weak for API payloads and config objects where a regression can keep returning the wrong keys while still being non-empty.

Incorrectโ€‹

it("returns config", () => {
    expect(Object.keys(loadConfig()).length).toBeGreaterThan(0);
});
it("returns config", () => {
    expect(Object.keys(loadConfig()).length).not.toBe(0);
});

Correctโ€‹

it("returns config", () => {
    expect(loadConfig()).toMatchObject({ mode: "production" });
});
it("returns config keys", () => {
    expect(Object.keys(loadConfig())).toEqual(["mode", "region"]);
});

What this rule reportsโ€‹

This rule reports executable it(...) and test(...) callbacks with broad non-empty key-count checks against Object.keys(...).length:

  • toBeGreaterThan(0)
  • toBeGreaterThanOrEqual(1)
  • not.toBe(0)
  • not.toHaveLength(0)

The rule intentionally does not flag exact key counts or computed thresholds.

Optionsโ€‹

This rule has no options.

When not to use itโ€‹

Disable this rule for tests whose real contract is only that an object is non-empty. Most product tests should assert the expected keys, shape, or values.

Rule catalog ID: R024