public void LoadPredefinedConnectionsShouldNotCrashWhenFileDoesNotExist() { // Arrange const string fileName = "non.existing"; var serializer = Substitute.For <ISerializer>(); if (File.Exists(fileName)) { File.Delete(fileName); } var sut = new ConfigurationSerializer(serializer); // Act var actual = sut.LoadPredefinedConnections(fileName); // Assert Assert.NotNull(actual); Assert.Empty(actual); }