An n-complete test suite for automata guarantees to detect all faulty implementations with a bounded number of states. This principle is well-known when testing FSMs for equivalence, but the problem becomes harder for ioco conformance on labeled transitions systems. Existing methods restrict the structure of specifications and implementations. We eliminate those restrictions, using only the number of implementation states, and fairness in test execution. We provide a formalization, a construction and a correctness proof for n-complete test suites for ioco.