metrics: Fix Metrics should have the correct labels test

`sriov_kubepoddevice` metric might end up in the Prometheus
database after a while, as the default scrape interval is 30s. This leads
to failures in the end-to-end lane like:

```
[sriov] Metrics Exporter When Prometheus operator is available [It] Metrics should have the correct labels
/root/opr-ocp2-1/data/sriov-network-operator/sriov-network-operator/test/conformance/tests/test_exporter_metrics.go:132

  [FAILED] no value for metric sriov_kubepoddevice
```

Put the metric assertion in an `Eventually` statement

Signed-off-by: Andrea Panattoni <[email protected]>

Author: zeeke

test/conformance/tests/test_exporter_metrics.go

@@ -158,15 +158,17 @@ var _ = Describe("[sriov] Metrics Exporter", Ordered, ContinueOnFailure, func()
 			}, "90s", "1s").Should(Succeed())
 
 			// sriov_kubepoddevice has a different sets of label than statistics metrics
-			samples := runPromQLQuery(fmt.Sprintf(`sriov_kubepoddevice{namespace="%s",pod="%s"}`, pod.Namespace, pod.Name))
-			Expect(samples).ToNot(BeEmpty(), "no value for metric sriov_kubepoddevice")
-			Expect(samples[0].Metric).To(And(
-				HaveKey(model.LabelName("pciAddr")),
-				HaveKeyWithValue(model.LabelName("node"), model.LabelValue(pod.Spec.NodeName)),
-				HaveKeyWithValue(model.LabelName("dev_type"), model.LabelValue("openshift.io/metricsResource")),
-				HaveKeyWithValue(model.LabelName("namespace"), model.LabelValue(pod.Namespace)),
-				HaveKeyWithValue(model.LabelName("pod"), model.LabelValue(pod.Name)),
-			))
+			Eventually(func(g Gomega) {
+				samples := runPromQLQuery(fmt.Sprintf(`sriov_kubepoddevice{namespace="%s",pod="%s"}`, pod.Namespace, pod.Name))
+				g.Expect(samples).ToNot(BeEmpty(), "no value for metric sriov_kubepoddevice")
+				g.Expect(samples[0].Metric).To(And(
+					HaveKey(model.LabelName("pciAddr")),
+					HaveKeyWithValue(model.LabelName("node"), model.LabelValue(pod.Spec.NodeName)),
+					HaveKeyWithValue(model.LabelName("dev_type"), model.LabelValue("openshift.io/metricsResource")),
+					HaveKeyWithValue(model.LabelName("namespace"), model.LabelValue(pod.Namespace)),
+					HaveKeyWithValue(model.LabelName("pod"), model.LabelValue(pod.Name)),
+				))
+			}, "60s", "1s").Should(Succeed())
 		})
 	})
 })