diff --git a/src/Microsoft.CodeAnalysis.Testing/Microsoft.CodeAnalysis.CodeFix.Testing/CodeFixTest`1.cs b/src/Microsoft.CodeAnalysis.Testing/Microsoft.CodeAnalysis.CodeFix.Testing/CodeFixTest`1.cs
index ff1d2c0650..411b8a0d8b 100644
--- a/src/Microsoft.CodeAnalysis.Testing/Microsoft.CodeAnalysis.CodeFix.Testing/CodeFixTest`1.cs
+++ b/src/Microsoft.CodeAnalysis.Testing/Microsoft.CodeAnalysis.CodeFix.Testing/CodeFixTest`1.cs
@@ -695,24 +695,35 @@ private async Task VerifyProjectAsync(ProjectState newState, Project project, IV
                     return (project, ExceptionDispatchInfo.Capture(ex));
                 }
 
+                var fixableDiagnostics = analyzerDiagnostics
+                    .Where(diagnostic => codeFixProviders.Any(provider => provider.FixableDiagnosticIds.Contains(diagnostic.diagnostic.Id)))
+                    .Where(diagnostic => project.Solution.GetDocument(diagnostic.diagnostic.Location.SourceTree) is object)
+                    .ToImmutableArray();
+
+                if (CodeFixTestBehaviors.HasFlag(CodeFixTestBehaviors.FixOne))
+                {
+                    var diagnosticToFix = TrySelectDiagnosticToFix(fixableDiagnostics.Select(x => x.diagnostic).ToImmutableArray());
+                    fixableDiagnostics = diagnosticToFix is object ? ImmutableArray.Create(fixableDiagnostics.Single(x => x.diagnostic == diagnosticToFix)) : ImmutableArray<(Project project, Diagnostic diagnostic)>.Empty;
+                }
+
                 Diagnostic? firstDiagnostic = null;
                 CodeFixProvider? effectiveCodeFixProvider = null;
                 string? equivalenceKey = null;
-                foreach (var (_, diagnostic) in analyzerDiagnostics)
+                foreach (var (_, diagnostic) in fixableDiagnostics)
                 {
                     var actions = new List<(CodeAction, CodeFixProvider)>();
 
+                    var diagnosticDocument = project.Solution.GetDocument(diagnostic.Location.SourceTree);
                     foreach (var codeFixProvider in codeFixProviders)
                     {
-                        if (!codeFixProvider.FixableDiagnosticIds.Contains(diagnostic.Id)
-                            || !(project.Solution.GetDocument(diagnostic.Location.SourceTree) is { } document))
+                        if (!codeFixProvider.FixableDiagnosticIds.Contains(diagnostic.Id))
                         {
                             // do not pass unsupported diagnostics to a code fix provider
                             continue;
                         }
 
                         var actionsBuilder = ImmutableArray.CreateBuilder<CodeAction>();
-                        var context = new CodeFixContext(document, diagnostic, (a, d) => actionsBuilder.Add(a), cancellationToken);
+                        var context = new CodeFixContext(diagnosticDocument, diagnostic, (a, d) => actionsBuilder.Add(a), cancellationToken);
                         await codeFixProvider.RegisterCodeFixesAsync(context).ConfigureAwait(false);
                         actions.AddRange(FilterCodeActions(actionsBuilder.ToImmutable()).Select(action => (action, codeFixProvider)));
                     }