Data-driven testing in NUnit?

Question

In MSTest you can do something like:

[TestMethod]
[DataSource(\"Microsoft.VisualStudio.TestTools.DataSource.CSV\", 
            \"testdata.csv\", \"testdata#         


        

Answer 1

Here is another example very similar to Tim Abell's however not using a framework for the CSV reader and showing the specifics of the test. Note when you use the TestCaseAttribute the TestAttribute can be omitted.

        [TestCaseSource("GetDataFromCSV")]
    public void TestDataFromCSV(int num1,int num2,int num3)
    {
        Assert.AreEqual(num1 + num2 ,num3);
    }

    private IEnumerable GetDataFromCSV()
    {
        CsvReader reader = new CsvReader(path);
        while (reader.Next())
        {
            int column1 = int.Parse(reader[0]);
            int column2 = int.Parse(reader[1]);
            int column3 = int.Parse(reader[2]);
            yield return new int[] { column1, column2, column3 };
        }
    }


public class CsvReader : IDisposable
{
    private string path;
    private string[] currentData;
    private StreamReader reader;

    public CsvReader(string path)
    {
        if (!File.Exists(path)) throw new InvalidOperationException("path does not exist");
        this.path = path;
        Initialize();
    }

    private void Initialize()
    {
        FileStream stream = new FileStream(path, FileMode.Open, FileAccess.Read);
        reader = new StreamReader(stream);
    }

    public bool Next()
    {
        string current = null;
        if ((current = reader.ReadLine()) == null) return false;
        currentData = current.Split(',');
        return true;
    }

    public string this[int index]
    {
        get { return currentData[index]; }
    }


    public void Dispose()
    {
        reader.Close();
    }
}

CSV Data:

10,200,210 20,190,210 30,180,210 40,170,210 50,160,210 60,150,210 70,140,210 80,130,210 90,120,210 100,110,210

Note: The 3rd column is a sum of the first two columns and this will be asserted in the unit test.

Results:

Find below an alternative using TestCaseData objects and setting a return type (which off-course is mandatory)

        [TestCaseSource("GetDataFromCSV2")]
    public int TestDataFromCSV2(int num1, int num2)
    {
        return num1 + num2;
    }

    private IEnumerable GetDataFromCSV2()
    {
        CsvReader reader = new CsvReader(path);
        while (reader.Next())
        {
            int column1 = int.Parse(reader[0]);
            int column2 = int.Parse(reader[1]);
            int column3 = int.Parse(reader[2]);
            yield return new TestCaseData(column1, column2).Returns(column3);
        }
    }