public void DetailsController_RegionDetails_IsNotNull() { // Arrange var regionInfo = new RegionDetails() { Name = "TestRegion" }; _mediator.Setup(s => s.GetRegionDetails("TestRegion")).ReturnsAsync(regionInfo); var controller = new DetailsController(_mediator.Object); // Act var result = controller.RegionDetails("TestRegion").Result; // Assert result.Should().NotBeNull(); }