Data Driven Test Removes Whitespace

Question

I am writing a unit test to test the following method.

public void MyMethod(string parm1)
{
    // Validate parm1.
    string[] invalidTokens = new string[] { "/", "{", "}", ".", "--", ";", " ", ",", "=", "(", ")", "\"", "'", "?" };
    foreach (string token in invalidTableTokens)
    {
        if (parm1.Contains(token))
            throw new ArgumentException("Parameter cannot contain \"" + token + "\".");
    }

    // No invalid characters so continue processing...
}

The unit test should verify that passing a string that contains an invalid character results in an exception. I want my unit test to be data driven with an XML (or CSV) datasource.

[TestMethod()]
[DeploymentItem("\\path\my_data.xml")]
[DataSource("Microsoft.VisualStudio.TestTools.DataSource.XML", "|DataDirectory|\\my_data.xml", "Token", DataAccessMethod.Sequential)]
public void MyMethod_Parm1ContainsInvalidCharacters_ThowsException()
{
    // Arrange
    string invalidToken = TestContext.DataRow["Token_Text"].ToString();
    MyClass sut = new MyClass ();

    // Act
    string errorMessage = "";
    try
    {
        sut.MyMethod(invalidToken);
    }
    catch (ArgumentException ex)
    {
        errorMessage = ex.Message;
    }

    // Assert
    Assert.AreEqual(errorMessage, "Parameter cannot contain \"" + invalidToken + "\".");
}

This works except when the tests needs to pass a single space character " ". Unfortunately, the value for Token_Text is always "" when I need it to be a space.

<?xml version="1.0" encoding="utf-8" ?>
<InvalidTokens>
  <Token>/</Token>
  <Token>{</Token>
  <Token>}</Token>
  <Token>.</Token>
  <Token>--</Token>
  <Token>;</Token>
  <Token> </Token> <!-- Fails here-->
  <Token Token_Text=" "/> <!-- Also fail here -->
  <Token>,</Token>
  <Token>=</Token>
  <Token>(</Token>
  <Token>)</Token>
  <Token>"</Token>
  <Token>'</Token>
  <Token>?</Token>
</InvalidTokens>

I have also tried this with the following CSV file and get the same results.

Token
"/"
"{"
"}"
"."
"--"
";"
" " <-- Fails  here
","
"="
"("
")"
""""
"'"
"?"

How can I represent a single space character for use in a data driven unit test?

Answer 1

I was able to represent a space by using special character decimal encoding.

<Token>&#032;</Token>