backport of commit 8c0b70c161 (#16337)

Co-authored-by: cskh <hui.kang@hashicorp.com>

test/integration/connect/envoy/case-dogstatsd-udp/verify.bats

@@ -20,12 +20,7 @@ load helpers
 }
 
 @test "s1 upstream should be able to connect to s2" {
-  run retry_default curl -s -f -d hello localhost:5000
-
-  echo "OUTPUT: $output"
-
-  [ "$status" == 0 ]
-  [ "$output" == "hello" ]
+  retry_default assert_upstream_message 5000
 }
 
 @test "s1 proxy should be sending metrics to statsd" {

test/integration/connect/envoy/case-statsd-udp/verify.bats

@@ -20,9 +20,7 @@ load helpers
 }
 
 @test "s1 upstream should be able to connect to s2" {
-  run retry_default curl -s -f -d hello localhost:5000
-  [ "$status" == 0 ]
-  [ "$output" == "hello" ]
+  retry_default assert_upstream_message 5000
 }
 
 @test "s1 proxy should be sending metrics to statsd" {

test/integration/connect/envoy/case-zipkin/verify.bats

@@ -28,9 +28,7 @@ load helpers
 }
 
 @test "s1 upstream should be able to connect to s2" {
-  run retry_default curl -s -f -d hello localhost:5000
-  [ "$status" == "0" ]
-  [ "$output" == "hello" ]
+  retry_default assert_upstream_message 5000
 }
 
 @test "s1 proxy should send trace spans to zipkin/jaeger" {

test/integration/connect/envoy/helpers.bash

@@ -46,6 +46,25 @@ function retry_long {
   retry 30 1 "$@"
 }
 
+# assert_upstream_message asserts both the returned code
+# and message from upstream service
+function assert_upstream_message {
+  local HOSTPORT=$1
+  run curl -s -d hello localhost:$HOSTPORT
+
+  if [ "$status" -ne 0 ]; then
+    echo "Command failed"
+    return 1
+  fi
+
+  if (echo $output | grep 'hello'); then
+    return 0
+  fi
+
+  echo "expected message not found in $output"
+  return 1
+}
+
 function is_set {
   # Arguments:
   #   $1 - string value to check its truthiness