public void write_data()
{
var file = new CsvFile();
file.WriteValues("1", "2", "3");
file.WriteValues("a", "b", "c");
file.WriteValues("foo", "bar", "foo,bar");
file.Contents().Trim().ShouldBe(@"
1,2,3
a,b,c
foo,bar,'foo,bar'
".Trim().Replace("'", "\""));
}