(With apologies for any transcription errors in the code below: I was testing this on a remote computer without copy/paste)
I tested the message
parameter as suggested by Manuel.
[Test]
public void LongTest()
{
string s1 = new string('.', 1000);
string s1 = new string('.', 500) + "+" + new string('.', 500);
Assert.That(s1, Is.EqualTo(s2));
}
and got the equivalent result to the one in the question:
Changing the Assert
to
Assert.That(s1, Is.EqualTo(s2), s1 + "\r\n\r\n" + s2);
changed the result to
which is possibly less than helpful, especially when the tooltip comes up showing you the entire thing. However, you can right-click on that area in the GUI runner and Copy it, and you do indeed get the whole text copied to the clipboard.