isDuplicate('key-1')); } public function test_second_call_is_duplicate(): void { $store = new InMemoryIdempotencyStore(); $store->isDuplicate('key-1'); self::assertTrue($store->isDuplicate('key-1')); } public function test_different_keys_are_independent(): void { $store = new InMemoryIdempotencyStore(); $store->isDuplicate('key-1'); self::assertFalse($store->isDuplicate('key-2')); } }