I am using Visual Studion 17.12.5 and I am experiencing the following problem.
After upgrading the MSTest-package from 3.7.3 to 3.8.0 and Microsoft.NET.Test.Sdk from 17.12.0 to 17.13.0 the most of my tests are ignored.
More precise: The Test-Explorer of Visual Studion gives a yellow warning-sign with most of the tests, but some ~ 2% are executed OK.
[...]
<ItemGroup>
<PackageReference Include="Microsoft.NET.Test.Sdk" Version="17.13.0" />
<PackageReference Include="MSTest" Version="3.8.0" />
<PackageReference Include="coverlet.collector" Version="6.0.4">
[...]

Reverting back to 3.7.3 and 17.12.0 all tests are executed normally:
[...]
<ItemGroup>
<PackageReference Include="Microsoft.NET.Test.Sdk" Version="17.12.0" />
<PackageReference Include="MSTest" Version="3.7.3" />
<PackageReference Include="coverlet.collector" Version="6.0.4">
[...]
for Code-Coverage I use Fine-Code-Coverage.
BTW: Isn’t it nice(!) that all tests appear green at first glance, only if you look closer you find out that 10152 tests have been skipped, and only 156 have been ok.
See and try code on my GitHub: https://github.com/joecare99/CSharp/tree/master/CSharpBible/Libraries
e.G: BaseLibTests, …
It happens to all targets .net4.6.2 – .net4.8.1 and .net6.0 – .net 9.0
Does anybody experience the same behavior or knows a solution ?
[Edit:]
With some investigation I found out that tests with “[DataRow(…)]”-attribute are skipped e.G:
/// <summary>
/// Test EnumMember-Helper function
/// </summary>
/// <param name="name">The name.</param>
/// <param name="peExp">The expected result</param>
[DataTestMethod()]
[DataRow(nameof(intProp), PropEnum.intProp)]
[DataRow(nameof(boolProp), PropEnum.boolProp)]
[DataRow(nameof(enumProp), PropEnum.enumProp)]
[DataRow(nameof(objectProp), PropEnum.objectProp)]
[DataRow(nameof(stringProp), PropEnum.stringProp)]
[DataRow("BlaBla", null)]
public void EnumMemberTest(string name, PropEnum? peExp)
{
Assert.AreEqual(peExp, typeof(PropEnum).EnumMember(name));
}
“normal” tests are executes ok. e.G:
/// <summary>
/// Test EnumMemberTest, to thow exception.
/// </summary>
[TestMethod()]
public void EnumMemberTest2()
{
Assert.ThrowsException<ArgumentException>(() => typeof(string).EnumMember("Hallo"));
}