### Question:
MutableHandlerRegistry extends HandlerRegistry { @Override @Nullable public ServerMethodDefinition<?, ?> lookupMethod(String methodName, @Nullable String authority) { String serviceName = MethodDescriptor.extractFullServiceName(methodName); if (serviceName == null) { return null; } ServerServiceDefinition service = services.get(serviceName); if (service == null) { return null; } return service.getMethod(methodName); }  @Nullable ServerServiceDefinition addService(ServerServiceDefinition service); @Nullable ServerServiceDefinition addService(BindableService bindableService); boolean removeService(ServerServiceDefinition service); @Override @ExperimentalApi("https://github.com/grpc/grpc-java/issues/2222") List<ServerServiceDefinition> getServices(); @Override @Nullable ServerMethodDefinition<?, ?> lookupMethod(String methodName, @Nullable String authority);  }### Answer:
@Test public void missingMethodLookupReturnsNull() { assertNull(registry.lookupMethod("bad")); }