[chore][receiver/kubeletstats] Introduce retry on test that rely on s…

…hared Informer sync (#33685)

**Description:** <Describe what has changed.>
<!--Ex. Fixing a bug - Describe the bug and how this fixes the issue.
Ex. Adding a feature - Explain what this achieves.-->

This PR introduces a "retry" check on the test that relies on the shared
node informer. This retry will ensure that the first valid scrape will
be after the informer has been "triggered" to handle the node's
addition.

**Link to tracking Issue:** <Issue number if applicable> Related to
#33681.

**Testing:** <Describe what testing was performed and which tests were
added.>

**Documentation:** <Describe the documentation added.>

---------

Signed-off-by: ChrsMark <[email protected]>
Co-authored-by: Tyler Helmuth <[email protected]>

receiver/kubeletstatsreceiver/scraper_test.go

@@ -9,8 +9,10 @@ import (
 	"os"
 	"path/filepath"
 	"testing"
+	"time"
 
 	"github.com/stretchr/testify/require"
+	"go.opentelemetry.io/collector/pdata/pmetric"
 	"go.opentelemetry.io/collector/receiver/receivertest"
 	"go.uber.org/zap"
 	"go.uber.org/zap/zaptest/observer"
@@ -134,9 +136,14 @@ func TestScraperWithNodeUtilization(t *testing.T) {
 		require.NoError(t, err)
 	}
 
-	md, err := r.Scrape(context.Background())
-	require.NoError(t, err)
-	require.Equal(t, numContainers+numPods, md.DataPointCount())
+	var md pmetric.Metrics
+	require.Eventually(t, func() bool {
+		md, err = r.Scrape(context.Background())
+		require.NoError(t, err)
+		return numContainers+numPods == md.DataPointCount()
+	}, 10*time.Second, 100*time.Millisecond,
+		"metrics not collected")
+
 	expectedFile := filepath.Join("testdata", "scraper", "test_scraper_cpu_util_nodelimit_expected.yaml")
 
 	// Uncomment to regenerate '*_expected.yaml' files