Add Nack handling to CS freshness test and localhop test

Bring implementation of localhop test in line with design

refs #3692

Change-Id: I40c49b68b03aa1996e5546465daaccc18e29853e
diff --git a/test_cs_freshness/README.md b/test_cs_freshness/README.md
index cd5d3b1..9d7d3ff 100644
--- a/test_cs_freshness/README.md
+++ b/test_cs_freshness/README.md
@@ -9,6 +9,6 @@
 5. Invoke ndnpeek to send Interest `ndn:/test-caching/A`, MustBeFresh=yes. Fail if this Interest is unanswered.
 6. Kill ndn-traffic-server. Check "total Interests received" equals 1.
 7. Pause 2000ms.
-8. Invoke ndnpeek to send Interest `ndn:/test-caching/A`, MustBeFresh=yes. Fail if this Interest is answered.
+8. Invoke ndnpeek to send Interest `ndn:/test-caching/A`, MustBeFresh=yes. Fail if this Interest is answered with Data.
 9. Invoke ndnpeek to send Interest `ndn:/test-caching/A` without MustBeFresh. Fail if this Interest is unanswered.
 
diff --git a/test_cs_freshness/cs-freshness-test.sh b/test_cs_freshness/cs-freshness-test.sh
index 65a0496..82e647b 100755
--- a/test_cs_freshness/cs-freshness-test.sh
+++ b/test_cs_freshness/cs-freshness-test.sh
@@ -41,16 +41,16 @@
 output=$(grep 'Total Interests Received' logs/server.log | head -1 | cut -d = -f2 | cut -d' ' -f2)
 if [[ $output != '1' ]]
 then
-    echo "FAIL: Expected ndn-traffic-server receives 1 interest. Actual: $output"
+    echo "FAIL: Expected ndn-traffic-server to receive 1 interest. Actual: $output"
     clean_up
     exit 3
 fi
 
-# Invoke ndnpeek to send Interest `ndn:/test-caching/A`, MustBeFresh=yes. Fail if this Interest is answered.
+# Invoke ndnpeek to send Interest `ndn:/test-caching/A`, MustBeFresh=yes. Fail if this Interest is answered with Data.
 output=$(ndnpeek -fp ndn:/test-caching/A)
-if [[ ! -z $output ]]
+if [[ $? == "0" ]]
 then
-    echo "FAIL: Expected no data received for third interest. Actual data received: '$output'"
+    echo "FAIL: Expected no data to be received in response to third interest. Received: '$output'"
     clean_up
     exit 4
 fi
diff --git a/test_cs_freshness/test_cs_freshness.py b/test_cs_freshness/test_cs_freshness.py
index f935f7a..4cd6b3e 100644
--- a/test_cs_freshness/test_cs_freshness.py
+++ b/test_cs_freshness/test_cs_freshness.py
@@ -28,7 +28,7 @@
         errormsg = {
             1 : "No data received for first interest",
             2 : "No data received for second interest",
-            3 : "ndn-traffic-server should receive exact 1 interest",
+            3 : "ndn-traffic-server should receive exactly 1 interest",
             4 : "Data received for third interest (expected no data received)",
             5 : "No data received for fourth interest",
         }