[Test]
public void ExecuteCommandWithAnInvalidParameter()
{
    string result = consoleCommands.ExecuteCommand("AddFloats 1 a");
    const string ExpectedEnglish =
        "Error: Can't process parameter no. 2: 'Input string was not in a correct format.'";
    const string ExpectedGerman =
        "Error: Can't process parameter no. 2: 'Die Eingabezeichenfolge hat das falsche Format.'";
    Assert.IsTrue(ExpectedEnglish.Equals(result) || ExpectedGerman.Equals(result));
}

[Test]
public void ExecuteCommandWithAnInvalidParameter()
{
    string result = consoleCommands.ExecuteCommand("AddFloats 1 a");
    const string ExpectedEnglish =
        "Error: Can't process parameter no. 2: 'Input string was not in a correct format.'";
    const string ExpectedGerman =
        "Error: Can't process parameter no. 2: 'Die Eingabezeichenfolge hat das falsche Format.'";
    Assert.IsTrue(ExpectedEnglish.Equals(result) || ExpectedGerman.Equals(result));
}