/// <summary>
/// General verifier for codefixes.
/// Creates a Document from the source string, then gets diagnostics on it and applies the relevant codefixes.
/// Then gets the string after the codefix is applied and compares it with the expected result.
/// Note: If any codefix causes new diagnostics to show up, the test fails unless allowNewCompilerDiagnostics is set to true.
/// </summary>
/// <param name="language">The language the source code is in</param>
/// <param name="analyzer">The analyzer to be applied to the source code</param>
/// <param name="codeFixProvider">The codefix to be applied to the code wherever the relevant Diagnostic is found</param>
/// <param name="oldSource">A class in the form of a string before the CodeFix was applied to it</param>
/// <param name="newSource">A class in the form of a string after the CodeFix was applied to it</param>
/// <param name="codeFixIndex">Index determining which codefix to apply if there are multiple</param>
/// <param name="allowNewCompilerDiagnostics">A bool controlling whether or not the test will fail if the CodeFix introduces other warnings after being applied</param>
private void VerifyFix(string language, DiagnosticAnalyzer analyzer, CodeFixProvider codeFixProvider, string oldSource, string newSource, int? codeFixIndex, bool allowNewCompilerDiagnostics)
{
var document = CreateDocument(oldSource, language);
var analyzerDiagnostics = GetSortedDiagnosticsFromDocuments(analyzer, new[] { document });
var compilerDiagnostics = GetCompilerDiagnostics(document);
var attempts = analyzerDiagnostics.Length;
for (int i = 0; i < attempts; ++i)
{
var actions = new List<CodeAction>();
var context = new CodeFixContext(document, analyzerDiagnostics[0], (a, d) => actions.Add(a), CancellationToken.None);
codeFixProvider.ComputeFixesAsync(context).Wait();
if (!actions.Any())
{
break;
}
if (codeFixIndex != null)
{
document = ApplyFix(document, actions.ElementAt((int)codeFixIndex));
break;
}
document = ApplyFix(document, actions.ElementAt(0));
analyzerDiagnostics = GetSortedDiagnosticsFromDocuments(analyzer, new[] { document });
var newCompilerDiagnostics = GetNewDiagnostics(compilerDiagnostics, GetCompilerDiagnostics(document));
//check if applying the code fix introduced any new compiler diagnostics
if (!allowNewCompilerDiagnostics && newCompilerDiagnostics.Any())
{
// Format and get the compiler diagnostics again so that the locations make sense in the output
document = document.WithSyntaxRoot(Formatter.Format(document.GetSyntaxRootAsync().Result, Formatter.Annotation, document.Project.Solution.Workspace));
newCompilerDiagnostics = GetNewDiagnostics(compilerDiagnostics, GetCompilerDiagnostics(document));
Assert.IsTrue(false,
string.Format("Fix introduced new compiler diagnostics:\r\n{0}\r\n\r\nNew document:\r\n{1}\r\n",
string.Join("\r\n", newCompilerDiagnostics.Select(d => d.ToString())),
document.GetSyntaxRootAsync().Result.ToFullString()));
}
//check if there are analyzer diagnostics left after the code fix
if (!analyzerDiagnostics.Any())
{
break;
}
}
//after applying all of the code fixes, compare the resulting string to the inputted one
var actual = GetStringFromDocument(document);
Assert.AreEqual(newSource, actual);
}
