public void VerifyGetFixableDiagnosticIds()
    {
      var fix = new FindSaveAssignmentIssueAnalyzerAddAssignmentCodeFix();
      var ids = fix.FixableDiagnosticIds.ToList();

      Assert.AreEqual(1, ids.Count, nameof(ids.Count));
      Assert.AreEqual(FindSaveAssignmentIssueAnalyzerConstants.DiagnosticId, ids[0],
        nameof(FindSaveAssignmentIssueAnalyzerConstants.DiagnosticId));
    }
    public async Task VerifyGetFixes()
    {
      var code = File.ReadAllText(
        $@"Targets\{nameof(FindSaveAssignmentIssueAnalyzerAddAssignmentCodeFixTests)}\{(nameof(this.VerifyGetFixes))}.cs");
      var document = TestHelpers.Create(code);
      var tree = await document.GetSyntaxTreeAsync();
      var diagnostics = await TestHelpers.GetDiagnosticsAsync(code, new FindSaveAssignmentIssueAnalyzer());
      var sourceSpan = diagnostics[0].Location.SourceSpan;

      var actions = new List<CodeAction>();
      var codeActionRegistration = new Action<CodeAction, ImmutableArray<Diagnostic>>(
        (a, _) => { actions.Add(a); });

      var fix = new FindSaveAssignmentIssueAnalyzerAddAssignmentCodeFix();
      var codeFixContext = new CodeFixContext(document, diagnostics[0],
        codeActionRegistration, new CancellationToken(false));
      await fix.RegisterCodeFixesAsync(codeFixContext);

      Assert.AreEqual(1, actions.Count, nameof(actions.Count));

      await TestHelpers.VerifyActionAsync(actions,
        FindSaveAssignmentIssueAnalyzerAddAssignmentCodeFixConstants.AddAssignmentDescription, document,
        tree, new[] { $@" = x" });
    }