public void ToMutable_should_return_expected_result() { var subject = new GridFSBucketOptions { BucketName = "bucket", ChunkSizeBytes = 123, ReadPreference = ReadPreference.Secondary, WriteConcern = WriteConcern.WMajority }.ToImmutable(); var result = subject.ToMutable(); result.BucketName.Should().Be(subject.BucketName); result.ChunkSizeBytes.Should().Be(subject.ChunkSizeBytes); result.ReadPreference.Should().Be(subject.ReadPreference); result.WriteConcern.Should().Be(subject.WriteConcern); }