public void TestPrint(string tag) { DateTime time = new DateTime(2019, 10, 29, 15, 55, 40, 200); Plane testPlane = new Plane { Tag = tag, CurrentTime = time }; testPlane.SeparationCond.Add("ABC1234"); // Setup test data File.Delete(path); _uut.Print(testPlane); // Act: Trigger the fake object to execute event invocation // Assert something here or use an NSubstitute Received Assert.IsTrue(File.Exists(path)); }