Merge pull request #34053 from bprashanth/trim_string

Automatic merge from submit-queue

Check for empty string post trimming

We curl in a retry loop and timeout,  trimming stdout to find endpoint names. When curl hits the timeout, stdout is empty, so we insert the empty string into the received set of endpoints. 

Fixes https://github.com/kubernetes/kubernetes/issues/32684

test/e2e/networking_utils.go

@@ -170,7 +170,10 @@ func (config *NetworkingTestConfig) dialFromContainer(protocol, containerIP, tar
 				continue
 			}
 			for _, hostName := range output["responses"] {
-				eps.Insert(hostName)
+				trimmed := strings.TrimSpace(hostName)
+				if trimmed != "" {
+					eps.Insert(trimmed)
+				}
 			}
 		}
 		framework.Logf("Waiting for endpoints: %v", expectedEps.Difference(eps))
@@ -217,7 +220,10 @@ func (config *NetworkingTestConfig) dialFromNode(protocol, targetIP string, targ
 			// we confirm unreachability.
 			framework.Logf("Failed to execute %v: %v", filterCmd, err)
 		} else {
-			eps.Insert(strings.TrimSpace(stdout))
+			trimmed := strings.TrimSpace(stdout)
+			if trimmed != "" {
+				eps.Insert(trimmed)
+			}
 		}
 		framework.Logf("Waiting for %+v endpoints, got endpoints %+v", expectedEps.Difference(eps), eps)