public void IsDigit() { for (char c = '0'; c <= '9'; c++) { Assert.IsTrue(CharBuffer.IsDigit(c)); } for (char c = 'a'; c <= 'z'; c++) { Assert.IsFalse(CharBuffer.IsDigit(c)); } for (char c = 'A'; c <= 'Z'; c++) { Assert.IsFalse(CharBuffer.IsDigit(c)); } }