public async Task UpdateSchemaVersion()
        {
            // arrange
            IMongoCollection <Schema> schemas =
                _mongoResource.CreateCollection <Schema>();
            IMongoCollection <SchemaVersion> versions =
                _mongoResource.CreateCollection <SchemaVersion>();
            IMongoCollection <SchemaPublishReport> publishReports =
                _mongoResource.CreateCollection <SchemaPublishReport>();

            var repository = new SchemaRepository(schemas, versions, publishReports);
            var schema     = new Schema("foo", "bar");
            await repository.AddSchemaAsync(schema);

            var schemaVersion = new SchemaVersion(
                schema.Id,
                "bar",
                "baz",
                new[]
            {
                new Tag("a", "b", DateTime.UtcNow)
            },
                DateTime.UtcNow);

            await repository.AddSchemaVersionAsync(schemaVersion);

            var updatedSchemaVersion = new SchemaVersion(
                schemaVersion.Id,
                schema.Id,
                "baz",
                "qux",
                new[]
            {
                new Tag("a", "b", DateTime.UtcNow)
            },
                DateTime.UtcNow);

            // act
            await repository.UpdateSchemaVersionAsync(updatedSchemaVersion);

            // assert
            SchemaVersion retrieved = await versions.AsQueryable()
                                      .Where(t => t.Id == schemaVersion.Id)
                                      .FirstOrDefaultAsync();

            Assert.NotNull(retrieved);
            Assert.Equal(schemaVersion.Id, retrieved.Id);
            Assert.Equal(schemaVersion.Published, retrieved.Published, TimeSpan.FromSeconds(1));
            Assert.Equal(schemaVersion.SchemaId, retrieved.SchemaId);
            Assert.Equal(updatedSchemaVersion.SourceText, retrieved.SourceText);
            Assert.Equal(updatedSchemaVersion.Hash, retrieved.Hash);
            Assert.Equal(updatedSchemaVersion.Tags.Count, retrieved.Tags.Count);
        }