/// <summary>
        ///     General method that gets a collection of actual diagnostics found in the source after the analyzer is run, then verifies each of them.
        /// </summary>
        /// <param name="sources">
        ///     An array of strings to create source documents from to run the analyzers on.
        /// </param>
        /// <param name="language">
        ///     The language of the classes represented by the source strings.
        /// </param>
        /// <param name="analyzer">
        ///     The analyzer to be run on the source code.
        /// </param>
        /// <param name="expected">
        ///     DiagnosticResults that should appear after the analyzer is run on the sources.</param>
        private void VerifyDiagnostics(string[] sources, string language, DiagnosticAnalyzer analyzer, params DiagnosticResult[] expected)
        {
            var diagnostics = DiagnosticVerifier.GetSortedDiagnostics(sources, language, analyzer);

            VerifyDiagnosticResults(diagnostics, analyzer, expected);
        }