How to test a value supplied via the pipeline to a C# cmdlet

Question

Assuming that I have a C# Cmdlet that accepts values from the pipeline:

[System.Management.Automation.Parameter(Position = 0, Mandatory = true, ValueFromPipeline=true)]
public string Query
{
    get { return query; }
    set { query = value; }
}
private string query;

I would test this:

[TestMethod()]
public void ShouldReturnAnInfoObjectCollection()
{

    // arrange
    string query = "SELECT si_id, si_name FROM ci_infoobjects WHERE si_id=23";
    InfoObjects actual = null;

    GetInfoObjects cmdlet = new GetInfoObjects();
    cmdlet.Query = query;

    // act
    IEnumerator result = cmdlet.Invoke().GetEnumerator();
    while (result.MoveNext())
    {
        actual = ((InfoObjects)result.Current);
    }

    // assert
    Assert.IsInstanceOfType(actual, typeof(InfoObjects));

}

How would I test this Cmdlet's ability to accept a value for Query via the pipeline?

Answer 1

Using Pipeline.Input for Powershell testing was helpful.

Configure runspace:

[ClassInitialize()]
public static void MyClassInitialize(TestContext testContext)
{
    config = RunspaceConfiguration.Create();
}

Create test:

[TestMethod()]
public void Get_InfoObjects_with_multiple_values_from_pipeline()
{

    // "SELECT ..." | Get-InfoObjects ...

    //
    // arrange
    //

    string[] queries = { "SELECT * FROM ci_infoobjects WHERE si_id=23", "SELECT * FROM ci_infoobjects WHERE si_id=4" };

    Command command = new Command("Get-InfoObjects");

    using (Runspace runspace = RunspaceFactory.CreateRunspace(config))
    {

        runspace.Open();

        using (Pipeline pipeline = runspace.CreatePipeline())
        {

            foreach (string query in queries)
            {
                pipeline.Input.Write(query);
            }

            pipeline.Commands.Add(command);

            //
            // act
            // 

            var actual = pipeline.Invoke();

            //
            // assert
            //

            Assert.AreEqual(1, actual.Count);
            Assert.IsInstanceOfType(actual[0], typeof(System.Management.Automation.PSObject));

        } // using Pipeline
    } // using // Runspace

} // test