public void WithWriteConcern_should_return_expected_result() { var originalWriteConcern = new WriteConcern(2); var subject = new MongoClient().WithWriteConcern(originalWriteConcern); var newWriteConcern = new WriteConcern(3); var result = subject.WithWriteConcern(newWriteConcern); subject.Settings.WriteConcern.Should().BeSameAs(originalWriteConcern); result.Settings.WriteConcern.Should().BeSameAs(newWriteConcern); result.WithWriteConcern(originalWriteConcern).Settings.Should().Be(subject.Settings); }