private void CharacterToken1() {
AssertTokenizer t = NewAssertTokenizer();
t.Load("?a")[Tokens.Character, "a"].EOF();
t.Load("?Σ")[Tokens.Character, "Σ"].EOF();
// surrogate:
string u12345 = Char.ConvertFromUtf32(0x12345);
t.Load("?" + u12345)[Tokens.Character, u12345].EOF();
// escapes:
t.Load(@"?\u{1}")[Tokens.Character, "\u0001"].EOF();
t.Load(@"?\u{}")[Tokens.Character, "\0"].Expect(Errors.InvalidUnicodeEscape);
t.Load(@"?\u{")[Tokens.Character, "\0"].Expect(Errors.UntermintedUnicodeEscape);
t.Load(@"?\u{1")[Tokens.Character, "\u0001"].Expect(Errors.UntermintedUnicodeEscape);
t.Load(@"?\u{1 2}")[Tokens.Character, "\u0001"].Expect(Errors.UntermintedUnicodeEscape);
t.Load(@"?\u{1123455}")[Tokens.Character, "?"].Expect(Errors.TooLargeUnicodeCodePoint);
}