public async void BadXmlThrowsKnowledgebaseException()
        {
            var ex = await Assert.ThrowsAsync <KnowledgebaseException>(
                () => _knowledgebase.GetSubjectAsync <Incidents>(KnowedgebaseSubjects.Tocs, CancellationToken.None));

            Assert.Equal("Error when deserialising xml for Tocs", ex.Message);
        }
        public async void SourceFailsThrowsKnowledgebaseException()
        {
            var knowledgebase = new Knowledgebase(
                new FileSource(TestFiles.TocFileOnly, Substitute.For <ILogger>()),
                Substitute.For <ILogger>());

            var ex = await Assert.ThrowsAsync <KnowledgebaseException>(
                () => knowledgebase.GetSubjectAsync <Incidents>(KnowedgebaseSubjects.Incidents, CancellationToken.None));

            Assert.Equal("Incidents file not configured", ex.Message);
        }