Clarify behavior when only the default unknown disk is returned

Author: Antoplt

test/integration/disk_test.go

@@ -18,11 +18,18 @@ func TestDiskMetricsContent(t *testing.T) {
 		t.Logf("Encountered partial errors collecting disk metrics: %v", errs)
 	}
 
-	// Verify that we retrieved at least some metrics
+	// If there are truly no metrics, or only the default "unknown" entry, skip in this environment.
 	if len(metricsSlice) == 0 {
 		t.Skip("No disk metrics found. This may indicate restricted disk access or a collection failure.")
 	}
 
+	if len(metricsSlice) == 1 {
+		if dd, ok := metricsSlice[0].(*metric.DiskData); ok &&
+			dd.Device == "unknown" && dd.Mountpoint == "unknown" {
+			t.Skip("Only default 'unknown' disk metric returned; disk metrics not available in this environment.")
+		}
+	}
+
 	foundValidDisk := false
 
 	for _, m := range metricsSlice {