diff --git a/test/210_dns_multicast_test.sh b/test/210_dns_multicast_test.sh
index bb83cec7..9629c12f 100755
--- a/test/210_dns_multicast_test.sh
+++ b/test/210_dns_multicast_test.sh
@@ -25,7 +25,6 @@ weave_on $HOST1 run --with-dns $C1/24 --name=c1 -t aanand/docker-dnsutils /bin/s
 
 assert_dns_record $HOST1 c1 $NAME $C2
 
-ok=$(exec_on $HOST1 c1 getent hosts 8.8.8.8)
-assert_raises "echo $ok | grep google"
+assert_raises "exec_on $HOST1 c1 getent hosts 8.8.8.8 | grep google"
 
 end_suite
diff --git a/test/300_fallback_dns_test.sh b/test/300_fallback_dns_test.sh
index bcaf5f9a..8e665efb 100755
--- a/test/300_fallback_dns_test.sh
+++ b/test/300_fallback_dns_test.sh
@@ -10,10 +10,7 @@ docker_on $HOST1 rm -f c1 || true
 
 weave_on $HOST1 run --with-dns 10.2.1.5/24 --name=c1 -t aanand/docker-dnsutils /bin/sh
 
-ok=$(exec_on $HOST1 c1 host -t mx weave.works)
-assert_raises "echo $ok | grep google"
-
-ok=$(exec_on $HOST1 c1 getent hosts 8.8.8.8)
-assert_raises "echo $ok | grep google"
+assert_raises "exec_on $HOST1 c1 host -t mx weave.works | grep google"
+assert_raises "exec_on $HOST1 c1 getent hosts 8.8.8.8   | grep google"
 
 end_suite
diff --git a/test/400_weave_local_test.sh b/test/400_weave_local_test.sh
index 2658a160..0b198951 100755
--- a/test/400_weave_local_test.sh
+++ b/test/400_weave_local_test.sh
@@ -11,8 +11,8 @@ assert_raises "docker_on $HOST1 ps | grep weave" 0
 
 docker_on $HOST1 rm -f c1 || true
 run_on $HOST1 sudo ./weave --local run 10.2.6.5/24 -ti --name=c1 ubuntu
-ok=$(exec_on $HOST1 c1 ifconfig | grep ethwe)
-assert "test -n \"$ok\" && echo pass" "pass"
+
+assert_raises "exec_on $HOST1 c1 ifconfig | grep ethwe"
 
 docker_on $HOST1 rm -f c1 || true
 
diff --git a/test/config.sh b/test/config.sh
index e4950b1e..02656018 100644
--- a/test/config.sh
+++ b/test/config.sh
@@ -90,10 +90,8 @@ exec_on() {
 
 # assert_dns_record <host> <container> <name> <ip>
 assert_dns_record() {
-    ok=$(exec_on $1 $2 getent hosts $3)
-    assert "echo $ok" "$4 $3"
-    ok=$(exec_on $1 $2 getent hosts $4)
-    assert "echo $ok" "$4 $3"
+    assert "exec_on $1 $2 getent hosts $3 | tr -s ' '" "$4 $3"
+    assert "exec_on $1 $2 getent hosts $4 | tr -s ' '" "$4 $3"
 }
 
 start_suite() {