Pass TFM into Buildalyzer build

src/Stryker.Core/Stryker.Core.UnitTest/Initialisation/BuildAnalyzerTestsBase.cs

@@ -253,6 +253,8 @@ internal Mock<IProjectAnalyzer> BuildProjectAnalyzerMock(string csprojPathName,
         projectAnalyzerMock.Setup(x => x.Build(It.IsAny<string[]>())).Returns(sourceProjectAnalyzerResultsMock);
         projectAnalyzerMock.Setup(x => x.Build(It.IsAny<string[]>(), It.IsAny<EnvironmentOptions>())).Returns(sourceProjectAnalyzerResultsMock);
         projectAnalyzerMock.Setup(x => x.Build(It.IsAny<EnvironmentOptions>())).Returns(sourceProjectAnalyzerResultsMock);
+        projectAnalyzerMock.Setup(x => x.Build(It.IsAny<string>())).Returns(sourceProjectAnalyzerResultsMock);
+        projectAnalyzerMock.Setup(x => x.Build(It.IsAny<string>(), It.IsAny<EnvironmentOptions>())).Returns(sourceProjectAnalyzerResultsMock);
         projectAnalyzerMock.Setup(x => x.Build()).Returns(sourceProjectAnalyzerResultsMock);
 
         projectAnalyzerMock.Setup(x => x.ProjectFile).Returns(projectFileMock.Object);

src/Stryker.Core/Stryker.Core.UnitTest/Initialisation/InputFileResolverTests.cs

@@ -908,7 +908,7 @@ public void ShouldSelectFrameworkBasedOnTestProject(string testFrameworks, strin
         var testProjectPath = Path.Combine(_sourcePath, "TestProjectFolder", "TestProject.csproj");
         var sourceProjectPath = Path.Combine(_sourcePath, "ExampleProject", "ExampleProject.csproj");
         var sourceProjectNameFilter = "ExampleProject.csproj";
-        
+
         var fileSystem = new MockFileSystem(new Dictionary<string, MockFileData>
         {
             { sourceProjectPath, new MockFileData(_defaultTestProjectFileContents)},

src/Stryker.Core/Stryker.Core/Initialisation/InputFileResolver.cs

@@ -9,6 +9,7 @@
 using Buildalyzer;
 using Buildalyzer.Environment;
 using Microsoft.Extensions.Logging;
+using NuGet.Frameworks;
 using Stryker.Abstractions.Exceptions;
 using Stryker.Abstractions.Logging;
 using Stryker.Abstractions.Options;
@@ -183,7 +184,7 @@ private IEnumerable<IAnalyzerResult> GetProjectAndAddIt(IStrykerOptions options,
         ConcurrentBag<(IEnumerable<IAnalyzerResult> result, bool isTest)> mutableProjectsAnalyzerResults)
     {
         var project = manager.GetProject(entry.projectFile);
-        IEnumerable<IAnalyzerResult> buildResult = AnalyzeSingleProject(project, options);
+        IEnumerable<IAnalyzerResult> buildResult = AnalyzeSingleProject(project, options, entry.framework);
         if (!buildResult.Any())
         {
             // analysis failed
@@ -237,7 +238,7 @@ private List<string> ScanReferences(ScanMode mode, IEnumerable<IAnalyzerResult>
         return referencesToAdd;
     }
 
-    private IAnalyzerResults AnalyzeSingleProject(IProjectAnalyzer project, IStrykerOptions options)
+    private IAnalyzerResults AnalyzeSingleProject(IProjectAnalyzer project, IStrykerOptions options, string targetFramework = null)
     {
         if (options.DevMode)
         {
@@ -246,7 +247,14 @@ private IAnalyzerResults AnalyzeSingleProject(IProjectAnalyzer project, IStryker
         }
         var projectLogName = Path.GetRelativePath(options.WorkingDirectory, project.ProjectFile.Path);
         _logger.LogDebug("Analyzing {ProjectFilePath}", projectLogName);
-        var buildResult = project.Build();
+
+        string bestFramework = null;
+        if (targetFramework is not null)
+        {
+            bestFramework = DetermineBestTargetFramework(project, targetFramework);
+        }
+
+        var buildResult = project.Build(bestFramework!);
 
         var buildResultOverallSuccess = buildResult.OverallSuccess || Array.
             TrueForAll(project.ProjectFile.TargetFrameworks, tf =>
@@ -273,7 +281,7 @@ private IAnalyzerResults AnalyzeSingleProject(IProjectAnalyzer project, IStryker
                 Restore = true
             };
             // retry the analysis
-            buildResult = project.Build(buildOptions);
+            buildResult = project.Build(bestFramework, buildOptions);
 
             // check the new status
             buildResultOverallSuccess = Array.TrueForAll(project.ProjectFile.TargetFrameworks, tf =>
@@ -302,6 +310,34 @@ private IAnalyzerResults AnalyzeSingleProject(IProjectAnalyzer project, IStryker
         return buildResult.All(br => !IsValid(br)) ? new AnalyzerResults() : buildResult;
     }
 
+    private string DetermineBestTargetFramework(IProjectAnalyzer project, string targetFramework)
+    {
+        var targetFrameworks = project.ProjectFile.TargetFrameworks;
+
+        if (targetFrameworks.Contains(targetFramework))
+        {
+            return targetFramework;
+        }
+
+        var reducer = new FrameworkReducer();
+        var framework = NuGetFramework.Parse(targetFramework);
+        var availableFrameworks = targetFrameworks.Select(NuGetFramework.Parse).ToList();
+
+        var nearest = reducer.GetNearest(framework, availableFrameworks);
+
+        if (nearest is null)
+        {
+            _logger.LogWarning("Could not find any compatible target frameworks for project '{ProjectFilePath}' that are compatible with '{TargetFramework}'.", project.ProjectFile.Path, targetFramework);
+            return null;
+        }
+
+        var bestFramework = nearest.GetShortFolderName();
+
+        _logger.LogInformation("Target framework '{TargetFramework}' not found in project '{ProjectFilePath}'. Using '{BestFramework}' instead.", targetFramework, project.ProjectFile.Path, bestFramework);
+
+        return bestFramework;
+    }
+
     private void LogAnalyzerResult(IAnalyzerResults analyzerResults, IStrykerOptions options)
     {
         // do not log if trace is not enabled
@@ -338,7 +374,7 @@ private void LogAnalyzerResult(IAnalyzerResults analyzerResults, IStrykerOptions
             {
                 if (importantProperties.Contains(property.Key))
                 {
-                    continue; // already logged 
+                    continue; // already logged
                 }
 
                 log.AppendLine($"Property {property.Key}={property.Value.Replace(Environment.NewLine, "\\n")}");