no-synthetic-promise-assertions

Disallow .resolves and .rejects assertions against synthetic Promise values.

Rule details

expect(Promise.resolve(...)).resolves and expect(Promise.reject(...)).rejects usually test JavaScript's built-in Promise behavior instead of the code under test. These assertions can make an async test look meaningful while never exercising the production function, adapter, or error path that should return the promise.

Incorrect

it("resolves", async () => {
    await expect(Promise.resolve("ok")).resolves.toBe("ok");
});

it("rejects", async () => {
    await expect(Promise.reject(new Error("boom"))).rejects.toThrow("boom");
});

Correct

it("loads the user", async () => {
    await expect(loadUser("user-1")).resolves.toEqual({ id: "user-1" });
});

it("rejects invalid input", async () => {
    await expect(saveUser({ id: "" })).rejects.toThrow("id is required");
});

What this rule reports

This rule reports executable it(...) and test(...) callbacks where an assertion chain combines .resolves or .rejects with an expect(...) subject that is directly created by Promise.resolve(...) or Promise.reject(...).

The rule intentionally does not flag non-global promise-like factories such as promiseFactory.resolve(...). Those helpers may be part of the behavior under test in a specific codebase.

Options

This rule has no options.

When not to use it

Disable this rule only for tests that intentionally document JavaScript Promise semantics. Product tests should assert a promise returned by the unit under test.

Rule catalog ID: R021