public void to_guid()
{
Assert.Throws <ArgumentNullException>(() => StringExtensions.ToGuid(null));
Assert.Throws <ArgumentException>(() => string.Empty.ToGuid());
const string Invalid = "invalid";
Assert.Equal(Guid.Empty, Guid.Empty.ToString().ToGuid());
Assert.Throws <FormatException>(() => Invalid.ToGuid());
Guid result;
Assert.True(Guid.Empty.ToString().ToGuid(out result));
Assert.Equal(Guid.Empty, result);
Assert.False(Invalid.ToGuid(out result));
Assert.Equal(default(Guid), result);
}
