public void Edits_Are_Applied_During_Full_Generation()
        {
            var source = @"
class C { }
";

            var         parseOptions = TestOptions.Regular;
            Compilation compilation  = CreateCompilation(source, options: TestOptions.DebugDll, parseOptions: parseOptions);

            compilation.VerifyDiagnostics();
            Assert.Single(compilation.SyntaxTrees);

            AdditionalFileAddedGenerator testGenerator = new AdditionalFileAddedGenerator();
            var text = new InMemoryAdditionalText("a\\file1.cs", "");

            GeneratorDriver driver = CSharpGeneratorDriver.Create(parseOptions: parseOptions,
                                                                  generators: ImmutableArray.Create <ISourceGenerator>(testGenerator),
                                                                  optionsProvider: CompilerAnalyzerConfigOptionsProvider.Empty,
                                                                  additionalTexts: ImmutableArray.Create <AdditionalText>(new InMemoryAdditionalText("a\\file1.cs", "")));

            driver.RunGeneratorsAndUpdateCompilation(compilation, out var outputCompilation, out _);
            Assert.Equal(2, outputCompilation.SyntaxTrees.Count());

            // add multiple edits
            driver = driver.WithPendingEdits(ImmutableArray.Create <PendingEdit>(new AdditionalFileAddedEdit(new InMemoryAdditionalText("a\\file2.cs", "")),
                                                                                 new AdditionalFileAddedEdit(new InMemoryAdditionalText("a\\file3.cs", "")),
                                                                                 new AdditionalFileAddedEdit(new InMemoryAdditionalText("a\\file4.cs", ""))));

            // but just do a full generation (don't try apply)
            driver.RunGeneratorsAndUpdateCompilation(compilation, out outputCompilation, out _);
            Assert.Equal(5, outputCompilation.SyntaxTrees.Count());
        }
        public void Added_Additional_File_With_Full_Generation()
        {
            var source = @"
class C { }
";

            var         parseOptions = TestOptions.Regular;
            Compilation compilation  = CreateCompilation(source, options: TestOptions.DebugDll, parseOptions: parseOptions);

            compilation.VerifyDiagnostics();
            Assert.Single(compilation.SyntaxTrees);

            AdditionalFileAddedGenerator testGenerator = new AdditionalFileAddedGenerator();
            var text = new InMemoryAdditionalText("a\\file1.cs", "");

            GeneratorDriver driver = CSharpGeneratorDriver.Create(parseOptions: parseOptions,
                                                                  generators: ImmutableArray.Create <ISourceGenerator>(testGenerator),
                                                                  optionsProvider: CompilerAnalyzerConfigOptionsProvider.Empty,
                                                                  additionalTexts: ImmutableArray.Create <AdditionalText>(new InMemoryAdditionalText("a\\file1.cs", "")));

            driver = driver.RunGeneratorsAndUpdateCompilation(compilation, out var outputCompilation, out _);

            // we should have a single extra file for the additional texts
            Assert.Equal(2, outputCompilation.SyntaxTrees.Count());

            // even if we run a full gen, or partial, nothing should change yet
            driver = driver.TryApplyEdits(outputCompilation, out var editedCompilation, out var succeeded);
            Assert.True(succeeded);
            Assert.Equal(2, editedCompilation.SyntaxTrees.Count());

            driver = driver.RunGeneratorsAndUpdateCompilation(compilation, out outputCompilation, out _);
            Assert.Equal(2, outputCompilation.SyntaxTrees.Count());

            // create an edit
            AdditionalFileAddedEdit edit = new AdditionalFileAddedEdit(new InMemoryAdditionalText("a\\file2.cs", ""));

            driver = driver.WithPendingEdits(ImmutableArray.Create <PendingEdit>(edit));

            // now try apply edits
            driver = driver.TryApplyEdits(compilation, out editedCompilation, out succeeded);
            Assert.True(succeeded);
            Assert.Equal(3, editedCompilation.SyntaxTrees.Count());

            // if we run a full compilation again, we should still get 3 syntax trees
            driver = driver.RunGeneratorsAndUpdateCompilation(compilation, out outputCompilation, out _);
            Assert.Equal(3, outputCompilation.SyntaxTrees.Count());
        }