added tests

Signed-off-by: Jan-Otto Kröpke <[email protected]>

internal/collector/mssql/mssql.go

@@ -272,6 +272,10 @@ func (c *Collector) Build(logger *slog.Logger, _ *mi.Session) error {
 // Collect sends the metric values for each metric
 // to the provided prometheus Metric channel.
 func (c *Collector) Collect(ch chan<- prometheus.Metric) error {
+	if len(c.mssqlInstances) == 0 {
+		return fmt.Errorf("no SQL instances found: %w", perfdata.ErrNoData)
+	}
+
 	errCh := make(chan error, len(c.collectorFns))
 	errs := make([]error, 0, len(c.collectorFns))
 

internal/collector/update/update.go

@@ -47,7 +47,10 @@ var ConfigDefaults = Config{
 	scrapeInterval: 6 * time.Hour,
 }
 
-var ErrNoUpdates = errors.New("pending gather update metrics")
+var (
+	ErrNoUpdates             = errors.New("pending gather update metrics")
+	ErrUpdateServiceDisabled = errors.New("windows updates service is disabled")
+)
 
 type Collector struct {
 	config Config
@@ -234,7 +237,7 @@ func (c *Collector) scheduleUpdateStatus(ctx context.Context, logger *slog.Logge
 	}(hc)
 
 	if err != nil {
-		initErrCh <- fmt.Errorf("windows updates service is disabled: %w", err)
+		initErrCh <- ErrUpdateServiceDisabled
 
 		return
 	}

internal/utils/testutils/testutils.go

@@ -113,7 +113,9 @@ func TestCollector[C collector.Collector, V interface{}](t *testing.T, fn func(*
 		errors.Is(err, perfdata.ErrNoData),
 		errors.Is(err, mi.MI_RESULT_INVALID_NAMESPACE),
 		errors.Is(err, mi.MI_RESULT_INVALID_QUERY),
-		errors.Is(err, update.ErrNoUpdates):
+		errors.Is(err, update.ErrNoUpdates),
+		errors.Is(err, update.ErrUpdateServiceDisabled):
+		t.Skip("collector not supported on this system")
 	default:
 		require.NoError(t, err)
 	}