Unit test TestContext Multiple calls

Question

I have a Test Method which is calling 2 Sub Test Methods. Both the sub Methods are Data Driven from an XML file. If I run each sub methods they run fine and successful. However, when I run Main Test Method (caller of both sub methods) it finds TestContext.DataConnection and TestContext.DataRow as null.

    private TestContext testContext;
    public TestContext TestContext
    {
        get { return testContext; }
        set { testContext = value; }
    }
    [TestMethod]
    public void SaveEmpty_Json_LocalStorage()
    {
        // Testing JSON Type format export and save
         SetWindowsUsers();
        // Add Network Information
        SetWifiInformation();

        // More logic and assertions here.
        // More logic and assertions here.
        // More logic and assertions here.
    }

    [TestMethod]
    [DeploymentItem("input.xml")]
    [DataSource("Microsoft.VisualStudio.TestTools.DataSource.XML",
               "input.xml",
               "User",
                DataAccessMethod.Sequential)]
    public void SetWindowsUsers()
    {
      Console.WriteLine(TestContext.DataRow["UserName"].ToString())
      // MORE LOGIC and Asserts  
    }

    [TestMethod]
    [DeploymentItem("input.xml")]
    [DataSource("Microsoft.VisualStudio.TestTools.DataSource.XML",
               "input.xml",
               "WifiList",
                DataAccessMethod.Sequential)]
    public void SetWifiInformation()
    {
      Console.WriteLine(TestContext.DataRow["SSID"].ToString())
      // MORE LOGIC and Asserts  
    }

If I Run All, 2 Methods pass and 1 fails. If I run individually, SaveData_Json_LocalStorage Does not pass, always gets TestContext.DataRow as null. Is it okay to call multiple methods inside. What is best way of writing chained test cases.

Answer 1

Chaining should only be done if one has to have non-recreate-able data. Otherwise make each test a distinct test.

Data Driven from an XML file.

Consider placing the read-only Xml into a property which is run once before thet tests in the ClassInitialization method. Then test the individual operations, followed by the "Main" operation, Each as a separate testable unit.

public static XDocument Xml { get; set; }

[DeploymentItem("input.xml")]
[DataSource("Microsoft.VisualStudio.TestTools.DataSource.XML",
           "input.xml",
           "User",
            DataAccessMethod.Sequential)]
[ClassInitialize()]
public static void ClassInit(TestContext context)
{ // This is done only once and used by other tests.
    Xml = ...
    Assert.IsTrue(Xml.Node ... );
}

---

Otherwise look into mocking the data depending on the test being performed or if it comes from a specific call, how about a shim? See my article Shim Saves The Day in A Tricky Unit Test Situation.