/// <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)
{
if (analyzer == null)
{
throw new ArgumentNullException(nameof(analyzer));
}
if (codeFixProvider == null)
{
throw new ArgumentNullException(nameof(codeFixProvider));
}
var document = DiagnosticVerifier.CreateDocument(oldSource, language);
var analyzerDiagnostics = DiagnosticVerifier.GetSortedDiagnosticsFromDocuments(analyzer, document);
var compilerDiagnostics = GetCompilerDiagnostics(document).ToArray();
var attempts = analyzerDiagnostics.Length;
for (var 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.RegisterCodeFixesAsync(context).Wait();
if (!actions.Any())
{
break;
}
if (codeFixIndex != null)
{
document = ApplyFix(document, actions.ElementAt(codeFixIndex.Value));
break;
}
document = ApplyFix(document, actions.ElementAt(0));
analyzerDiagnostics = DiagnosticVerifier.GetSortedDiagnosticsFromDocuments(analyzer, 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.Fail(
"Fix introduced new compiler diagnostics. " +
$"\r\n{document.GetSyntaxRootAsync().Result.ToFullString()}" +
$"\r\n\r\n{string.Join(Environment.NewLine, newCompilerDiagnostics.Select(d => d.ToString()))}");
}
//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, "Expected document is not the same as the resulting one.");
}
