Revise `TryGetProjectOrSolutionFilePath` and `GetSolutionFilePaths` logic for the new dotnet test experience

[Youssef1313]

sdk/src/Cli/dotnet/commands/dotnet-test/SolutionAndProjectUtility.cs

Lines 87 to 88 in 9f73261

	string[] solutionFiles = Directory.GetFiles(directory, CliConstants.SolutionExtensionPattern, SearchOption.TopDirectoryOnly);
	solutionFiles.AddRange(Directory.GetFiles(directory, CliConstants.SolutionXExtensionPattern, SearchOption.TopDirectoryOnly));

The second line above should crash. An array is fixed-length. It's implicitly converted to ICollection<string> in that code path and should throw some exception at run-time.

---

sdk/src/Cli/dotnet/commands/dotnet-test/SolutionAndProjectUtility.cs

Lines 19 to 83 in 9f73261

	public static (bool SolutionOrProjectFileFound, string Message) TryGetProjectOrSolutionFilePath(string directory, out string projectOrSolutionFilePath, out bool isSolution)
	{
	projectOrSolutionFilePath = string.Empty;
	isSolution = false;
	if (!Directory.Exists(directory))
	{
	return (false, string.Format(LocalizableStrings.CmdNonExistentDirectoryErrorDescription, directory));
	}
	var solutionPaths = GetSolutionFilePaths(directory);
	// If more than a single sln file is found, an error is thrown since we can't determine which one to choose.
	if (solutionPaths.Length > 1)
	{
	return (false, string.Format(CommonLocalizableStrings.MoreThanOneSolutionInDirectory, directory));
	}
	if (solutionPaths.Length == 1)
	{
	var projectPaths = GetProjectFilePaths(directory);
	if (projectPaths.Length == 0)
	{
	projectOrSolutionFilePath = solutionPaths[0];
	isSolution = true;
	return (true, string.Empty);
	}
	return (false, LocalizableStrings.CmdMultipleProjectOrSolutionFilesErrorDescription);
	}
	else // If no solutions are found, look for a project file
	{
	string[] projectPaths = GetProjectFilePaths(directory);
	if (projectPaths.Length == 0)
	{
	var solutionFilterPaths = GetSolutionFilterFilePaths(directory);
	if (solutionFilterPaths.Length == 0)
	{
	return (false, LocalizableStrings.CmdNoProjectOrSolutionFileErrorDescription);
	}
	if (solutionFilterPaths.Length == 1)
	{
	projectOrSolutionFilePath = solutionFilterPaths[0];
	isSolution = true;
	return (true, string.Empty);
	}
	else
	{
	return (false, LocalizableStrings.CmdMultipleProjectOrSolutionFilesErrorDescription);
	}
	}
	if (projectPaths.Length == 1)
	{
	projectOrSolutionFilePath = projectPaths[0];
	return (true, string.Empty);
	}
	return (false, string.Format(CommonLocalizableStrings.MoreThanOneSolutionInDirectory, directory));
	}
	}

I'm reading this logic as "If there are no sln/slnx files at all, and a single project file is found, use the project file". But what if the directory has slnf and project file, without sln/slnx? I think we should either prefer the slnf, or error. It's a pattern I have never seen, but ...

Anyways, we should validate the behavior of dotnet build, and make sure we match it, and share some common helpers if needed.

[mariam-abdulla]

For fixing GetSolutionFilePaths, good catch. I will fix it.

However, when we have both slnf and project file together in the same directory. We have the same behavior as msbuild which is considering the project file and ignoring the slnf.

[Youssef1313]

Interesting. @rainersigwald Are the rules for what to consider documented somewhere?

I'm wondering if some of the current behavior are only for backcompat reasons. Maybe we could consider some scenarios as "ambiguous" and do error for the new dotnet test experience as we don't really have backcompat concerns?

[Youssef1313]

I'm re-opening as the second part of this issue wasn't addressed. Ping @rainersigwald @baronfel for what rules we should follow here.