Only check top 20 matches for v3 node search tests (#1483)

The order of lower matches can be nondeterministic, so this is just to
help make tests less flaky

internal/server/spanner/golden/query_test.go

@@ -26,6 +26,11 @@ import (
 	"github.com/google/go-cmp/cmp"
 )
 
+const (
+	// Number of matches to validate for SearchNodes tests.
+	NUM_SEARCH_MATCHES = 20
+)
+
 func TestGetNodeProps(t *testing.T) {
 	client := test.NewSpannerClient()
 	if client == nil {
@@ -321,7 +326,10 @@ func TestSearchNodes(t *testing.T) {
 			t.Fatalf("SearchNodes error (%v): %v", c.goldenFile, err)
 		}
 
-		got, err := test.StructToJSON(actual)
+		// Filter actual to top matches to avoid flaky low matches.
+		topResp := actual[:NUM_SEARCH_MATCHES]
+
+		got, err := test.StructToJSON(topResp)
 		if err != nil {
 			t.Fatalf("StructToJSON error (%v): %v", c.goldenFile, err)
 		}

internal/server/v3/nodesearch/golden/node_search_test.go

@@ -27,6 +27,11 @@ import (
 	"google.golang.org/protobuf/testing/protocmp"
 )
 
+const (
+	// Number of matches to validate for NodeSearch tests.
+	NUM_SEARCH_MATCHES = 20
+)
+
 func TestV3NodeSearch(t *testing.T) {
 	// TODO: Remove check once enabled.
 	if !test.EnableSpannerGraph {
@@ -63,19 +68,25 @@ func TestV3NodeSearch(t *testing.T) {
 				t.Errorf("Could not run V3NodeSearch: %s", err)
 				continue
 			}
+
+			// Filter resp to top matches to avoid flaky low matches.
+			topResp := &pbv3.NodeSearchResponse{
+				Nodes: resp.Nodes[:NUM_SEARCH_MATCHES],
+			}
+
 			if latencyTest {
 				continue
 			}
 			if test.GenerateGolden {
-				test.UpdateGolden(resp, goldenPath, goldenFile)
+				test.UpdateGolden(topResp, goldenPath, goldenFile)
 				continue
 			}
 			var expected pbv3.NodeSearchResponse
 			if err = test.ReadJSON(goldenPath, goldenFile, &expected); err != nil {
 				t.Errorf("Could not Unmarshal golden file: %s", err)
 				continue
 			}
-			if diff := cmp.Diff(resp, &expected, protocmp.Transform()); diff != "" {
+			if diff := cmp.Diff(topResp, &expected, protocmp.Transform()); diff != "" {
 				t.Errorf("%s: got diff: %s", goldenFile, diff)
 				continue
 			}