Need clean way to share data between parameterized tests

[JVimes]

MSTest v2 needs a clean way to share test-data between tests. It should support objects.

Current approaches fall short:

• DataRow can't be shared and doesn't support objects (just compile-time values).
• DataSource doesn't support objects, and requires a database/csv.
• Looping through an array/collection lumps the cases into a single test, making test results less readable.

Suggest adding the equivalent of NUnit's TestCaseSource, which takes the name of a field, property, or method that returns an IEnumerable (which can handle objects):

static object[] DivideCases =
{
    new object[] { 12, 3, 4 },
    new object[] { 12, 2, 6 },
    new object[] { 12, 4, 3 } 
};

[Test, TestCaseSource("DivideCases")]
public void DivideTest(int n, int d, int q)
{
    Assert.AreEqual( q, n / d );
}

[AbhitejJohn]

Absolutely. Thanks for filing this @JVimes . This should also help drive a structure around #141.

[JVimes]

This is being discussed in: microsoft/testfx-docs#12

[AbhitejJohn]

This has been addressed in 1.2.0-beta release of the Framework/Adapter pair.

[JVimes]

Thanks! For others who find this, here's how to try it out:

Make sure you have MSTest v1.2.0 or later. At time of writing it's in beta, so need to install yourself using NuGet's "Include prerelease" checkbox:

Then, add a static, object[][] property to your test class. Fill in data. Add[DynamicData("ThePropertyName")] to your method, and make sure it has the right number/type of parameters:

static object[] Data
{
    get => new[]
    {
        new object[] {1, 2, 3},
        new object[] {4, 5, 6}
    };
}
        
[TestMethod]
[DynamicData("Data")]
public void Test1(int a, int b, int c)
{
    Assert.AreEqual(1, a % 3);
    Assert.AreEqual(2, b % 3);
    Assert.AreEqual(0, c % 3);
}

You can alternatively use a method that returns an IEnumerable<object[]>, instead of a property. I'm going off this doc.