Visual Studio doesn't discover my unit tests!

I added a unit test class to a project today, and Visual Studio couldn't find my new unit tests. Quick hack: modify your output window to "Show output from:" "Tests." This may help you find the reason why. In my case, it told me pretty directly what the issue was:

UTA001: TestClass attribute defined on non-public class MyTests

My test class wasn't public, which it appears is a requirement for discovery.

Downloading an ISO for Visual Studio 2017

Note to Self

There isn't an ISO image download for VS 2017, you download the web installer, then pass it the commands to construct a disk layout for you. Here's the location of instructions to do so:

    Create an offline installer for Visual Studio 2017

That page includes instructions for:

• Creating an offline installation layout.
• Installing from an offline installation layout (may not be necessary, see the comments on this instruction).
• Customizing the offline installer.
• Updating the offline installer.
• Troubleshooting.

And here's the command line I use:

    vs_Community.exe --layout c:\vs2017-community-en-US-offline --lang en-US