Under the Nigerian legal system, customary law is an essential source of law but must satisfy certain statutory validity tests before it can be enforced by the courts. Which test specifically requires that a rule of customary law must NOT be contrary to any existing statutory enactment for the time being in force in Nigeria?

The Incompatibility Test mandates that no rule of customary law shall be enforced if it is incompatible, either directly or by necessary implication, with any written law (statute) currently in force in Nigeria. The Repugnancy Test requires that it must not be repugnant to natural justice, equity, and good conscience, while the Public Policy Test ensures it does not run contrary to public policy.