tests: shell: Search diff tool once and for all

Instead of calling 'which diff' over and over again, just detect the
tool's presence in run-tests.sh and pass $DIFF to each testcase just
like with nft binary.

Fall back to using 'true' command to avoid the need for any conditional
calling in test cases.

While being at it, unify potential diff calls so that a string
comparison in shell happens irrespective of diff presence.

Signed-off-by: Phil Sutter <phil@nwl.cc>
Acked-by: Pablo Neira Ayuso <pablo@netfilter.org>

32 files changed, 40 insertions, 74 deletions

diff --git a/tests/shell/testcases/flowtable/0010delete_handle_0 b/tests/shell/testcases/flowtable/0010delete_handle_0
index 985d4a3a..8dd8d9fd 100755
--- a/tests/shell/testcases/flowtable/0010delete_handle_0
+++ b/tests/shell/testcases/flowtable/0010delete_handle_0
@@ -16,7 +16,6 @@ EXPECTED="table inet t {
 
 GET="$($NFT list ruleset)"
 if [ "$EXPECTED" != "$GET" ] ; then
-	DIFF="$(which diff)"
-	[ -x $DIFF ] && $DIFF -u <(echo "$EXPECTED") <(echo "$GET")
+	$DIFF -u <(echo "$EXPECTED") <(echo "$GET")
 	exit 1
 fi
diff --git a/tests/shell/testcases/listing/0003table_0 b/tests/shell/testcases/listing/0003table_0
index 1b288e43..5060be01 100755
--- a/tests/shell/testcases/listing/0003table_0
+++ b/tests/shell/testcases/listing/0003table_0
@@ -11,15 +11,13 @@ $NFT add table test
 
 GET="$($NFT list table test)"
 if [ "$EXPECTED" != "$GET" ] ; then
-	DIFF="$(which diff)"
-	[ -x $DIFF ] && $DIFF -u <(echo "$EXPECTED") <(echo "$GET")
+	$DIFF -u <(echo "$EXPECTED") <(echo "$GET")
 	exit 1
 fi
 
 # also this way
 GET="$($NFT list table ip test)"
 if [ "$EXPECTED" != "$GET" ] ; then
-	DIFF="$(which diff)"
-	[ -x $DIFF ] && $DIFF -u <(echo "$EXPECTED") <(echo "$GET")
+	$DIFF -u <(echo "$EXPECTED") <(echo "$GET")
 	exit 1
 fi
diff --git a/tests/shell/testcases/listing/0004table_0 b/tests/shell/testcases/listing/0004table_0
index 2c7c9952..1d69119f 100755
--- a/tests/shell/testcases/listing/0004table_0
+++ b/tests/shell/testcases/listing/0004table_0
@@ -12,8 +12,7 @@ $NFT add table test2
 
 GET="$($NFT list table test)"
 if [ "$EXPECTED" != "$GET" ] ; then
-	DIFF="$(which diff)"
-	[ -x $DIFF ] && $DIFF -u <(echo "$EXPECTED") <(echo "$GET")
+	$DIFF -u <(echo "$EXPECTED") <(echo "$GET")
 	exit 1
 fi
 
diff --git a/tests/shell/testcases/listing/0005ruleset_ip_0 b/tests/shell/testcases/listing/0005ruleset_ip_0
index c3266806..39c03282 100755
--- a/tests/shell/testcases/listing/0005ruleset_ip_0
+++ b/tests/shell/testcases/listing/0005ruleset_ip_0
@@ -15,7 +15,6 @@ $NFT add table bridge test
 
 GET="$($NFT list ruleset ip)"
 if [ "$EXPECTED" != "$GET" ] ; then
-	DIFF="$(which diff)"
-	[ -x $DIFF ] && $DIFF -u <(echo "$EXPECTED") <(echo "$GET")
+	$DIFF -u <(echo "$EXPECTED") <(echo "$GET")
 	exit 1
 fi
diff --git a/tests/shell/testcases/listing/0006ruleset_ip6_0 b/tests/shell/testcases/listing/0006ruleset_ip6_0
index 093d5a57..1b67f50c 100755
--- a/tests/shell/testcases/listing/0006ruleset_ip6_0
+++ b/tests/shell/testcases/listing/0006ruleset_ip6_0
@@ -15,7 +15,6 @@ $NFT add table bridge test
 
 GET="$($NFT list ruleset ip6)"
 if [ "$EXPECTED" != "$GET" ] ; then
-	DIFF="$(which diff)"
-	[ -x $DIFF ] && $DIFF -u <(echo "$EXPECTED") <(echo "$GET")
+	$DIFF -u <(echo "$EXPECTED") <(echo "$GET")
 	exit 1
 fi
diff --git a/tests/shell/testcases/listing/0007ruleset_inet_0 b/tests/shell/testcases/listing/0007ruleset_inet_0
index b24cc4c0..257c7a90 100755
--- a/tests/shell/testcases/listing/0007ruleset_inet_0
+++ b/tests/shell/testcases/listing/0007ruleset_inet_0
@@ -15,7 +15,6 @@ $NFT add table bridge test
 
 GET="$($NFT list ruleset inet)"
 if [ "$EXPECTED" != "$GET" ] ; then
-	DIFF="$(which diff)"
-	[ -x $DIFF ] && $DIFF -u <(echo "$EXPECTED") <(echo "$GET")
+	$DIFF -u <(echo "$EXPECTED") <(echo "$GET")
 	exit 1
 fi
diff --git a/tests/shell/testcases/listing/0008ruleset_arp_0 b/tests/shell/testcases/listing/0008ruleset_arp_0
index fff0fee3..be42c478 100755
--- a/tests/shell/testcases/listing/0008ruleset_arp_0
+++ b/tests/shell/testcases/listing/0008ruleset_arp_0
@@ -15,7 +15,6 @@ $NFT add table bridge test
 
 GET="$($NFT list ruleset arp)"
 if [ "$EXPECTED" != "$GET" ] ; then
-	DIFF="$(which diff)"
-	[ -x $DIFF ] && $DIFF -u <(echo "$EXPECTED") <(echo "$GET")
+	$DIFF -u <(echo "$EXPECTED") <(echo "$GET")
 	exit 1
 fi
diff --git a/tests/shell/testcases/listing/0009ruleset_bridge_0 b/tests/shell/testcases/listing/0009ruleset_bridge_0
index 247ed477..c6a99f50 100755
--- a/tests/shell/testcases/listing/0009ruleset_bridge_0
+++ b/tests/shell/testcases/listing/0009ruleset_bridge_0
@@ -15,7 +15,6 @@ $NFT add table bridge test
 
 GET="$($NFT list ruleset bridge)"
 if [ "$EXPECTED" != "$GET" ] ; then
-	DIFF="$(which diff)"
-	[ -x $DIFF ] && $DIFF -u <(echo "$EXPECTED") <(echo "$GET")
+	$DIFF -u <(echo "$EXPECTED") <(echo "$GET")
 	exit 1
 fi
diff --git a/tests/shell/testcases/listing/0010sets_0 b/tests/shell/testcases/listing/0010sets_0
index 855cceb8..0f5f2bd5 100755
--- a/tests/shell/testcases/listing/0010sets_0
+++ b/tests/shell/testcases/listing/0010sets_0
@@ -57,7 +57,6 @@ $NFT add set inet filter set2 { type icmpv6_type \; }
 
 GET="$($NFT list sets)"
 if [ "$EXPECTED" != "$GET" ] ; then
-	DIFF="$(which diff)"
-	[ -x $DIFF ] && $DIFF -u <(echo "$EXPECTED") <(echo "$GET")
+	$DIFF -u <(echo "$EXPECTED") <(echo "$GET")
 	exit 1
 fi
diff --git a/tests/shell/testcases/listing/0011sets_0 b/tests/shell/testcases/listing/0011sets_0
index aac9eac9..b6f12b59 100755
--- a/tests/shell/testcases/listing/0011sets_0
+++ b/tests/shell/testcases/listing/0011sets_0
@@ -38,7 +38,6 @@ $NFT add rule inet filter test tcp dport {80, 443}
 GET="$($NFT list sets)"
 
 if [ "$EXPECTED" != "$GET" ] ; then
-	DIFF="$(which diff)"
-	[ -x $DIFF ] && $DIFF -u <(echo "$EXPECTED") <(echo "$GET")
+	$DIFF -u <(echo "$EXPECTED") <(echo "$GET")
 	exit 1
 fi
diff --git a/tests/shell/testcases/listing/0012sets_0 b/tests/shell/testcases/listing/0012sets_0
index da16d94d..6e4c9590 100755
--- a/tests/shell/testcases/listing/0012sets_0
+++ b/tests/shell/testcases/listing/0012sets_0
@@ -33,7 +33,6 @@ $NFT add set inet filter set2 { type icmpv6_type \; }
 
 GET="$($NFT list sets inet)"
 if [ "$EXPECTED" != "$GET" ] ; then
-	DIFF="$(which diff)"
-	[ -x $DIFF ] && $DIFF -u <(echo "$EXPECTED") <(echo "$GET")
+	$DIFF -u <(echo "$EXPECTED") <(echo "$GET")
 	exit 1
 fi
diff --git a/tests/shell/testcases/listing/0013objects_0 b/tests/shell/testcases/listing/0013objects_0
index f6915796..4d39143d 100755
--- a/tests/shell/testcases/listing/0013objects_0
+++ b/tests/shell/testcases/listing/0013objects_0
@@ -42,7 +42,6 @@ $NFT add table test-ip
 
 GET="$($NFT list table test)"
 if [ "$EXPECTED" != "$GET" ] ; then
-	DIFF="$(which diff)"
-	[ -x $DIFF ] && $DIFF -u <(echo "$EXPECTED") <(echo "$GET")
+	$DIFF -u <(echo "$EXPECTED") <(echo "$GET")
 	exit 1
 fi
diff --git a/tests/shell/testcases/listing/0014objects_0 b/tests/shell/testcases/listing/0014objects_0
index 20f68406..31d94f86 100755
--- a/tests/shell/testcases/listing/0014objects_0
+++ b/tests/shell/testcases/listing/0014objects_0
@@ -17,15 +17,13 @@ $NFT add table test-ip
 
 GET="$($NFT list quotas)"
 if [ "$EXPECTED" != "$GET" ] ; then
-	DIFF="$(which diff)"
-	[ -x $DIFF ] && $DIFF -u <(echo "$EXPECTED") <(echo "$GET")
+	$DIFF -u <(echo "$EXPECTED") <(echo "$GET")
 	exit 1
 fi
 
 GET="$($NFT list quota test https-quota)"
 if [ "$EXPECTED" != "$GET" ] ; then
-	DIFF="$(which diff)"
-	[ -x $DIFF ] && $DIFF -u <(echo "$EXPECTED") <(echo "$GET")
+	$DIFF -u <(echo "$EXPECTED") <(echo "$GET")
 	exit 1
 fi
 
diff --git a/tests/shell/testcases/listing/0015dynamic_0 b/tests/shell/testcases/listing/0015dynamic_0
index 4ff74e32..65fbe62c 100755
--- a/tests/shell/testcases/listing/0015dynamic_0
+++ b/tests/shell/testcases/listing/0015dynamic_0
@@ -16,8 +16,7 @@ $NFT -f - <<< "$EXPECTED"
 
 GET="$($NFT list set ip filter test_set)"
 if [ "$EXPECTED" != "$GET" ] ; then
-	DIFF="$(which diff)"
-	[ -x $DIFF ] && $DIFF -u <(echo "$EXPECTED") <(echo "$GET")
+	$DIFF -u <(echo "$EXPECTED") <(echo "$GET")
 	exit 1
 fi
 
diff --git a/tests/shell/testcases/listing/0017objects_0 b/tests/shell/testcases/listing/0017objects_0
index 8a586e80..c4e72db0 100755
--- a/tests/shell/testcases/listing/0017objects_0
+++ b/tests/shell/testcases/listing/0017objects_0
@@ -13,7 +13,6 @@ $NFT flush map inet filter countermap
 
 GET="$($NFT list map inet filter countermap)"
 if [ "$EXPECTED" != "$GET" ] ; then
-	DIFF="$(which diff)"
-	[ -x $DIFF ] && $DIFF -u <(echo "$EXPECTED") <(echo "$GET")
+	$DIFF -u <(echo "$EXPECTED") <(echo "$GET")
 	exit 1
 fi
diff --git a/tests/shell/testcases/listing/0018data_0 b/tests/shell/testcases/listing/0018data_0
index 544b6bf5..4af253dc 100755
--- a/tests/shell/testcases/listing/0018data_0
+++ b/tests/shell/testcases/listing/0018data_0
@@ -13,7 +13,6 @@ $NFT flush map inet filter ipmap
 
 GET="$($NFT list map inet filter ipmap)"
 if [ "$EXPECTED" != "$GET" ] ; then
-	DIFF="$(which diff)"
-	[ -x $DIFF ] && $DIFF -u <(echo "$EXPECTED") <(echo "$GET")
+	$DIFF -u <(echo "$EXPECTED") <(echo "$GET")
 	exit 1
 fi
diff --git a/tests/shell/testcases/listing/0019set_0 b/tests/shell/testcases/listing/0019set_0
index 54a8a064..6e8cb4d6 100755
--- a/tests/shell/testcases/listing/0019set_0
+++ b/tests/shell/testcases/listing/0019set_0
@@ -13,7 +13,6 @@ $NFT flush set inet filter ipset
 
 GET="$($NFT list set inet filter ipset)"
 if [ "$EXPECTED" != "$GET" ] ; then
-	DIFF="$(which diff)"
-	[ -x $DIFF ] && $DIFF -u <(echo "$EXPECTED") <(echo "$GET")
+	$DIFF -u <(echo "$EXPECTED") <(echo "$GET")
 	exit 1
 fi
diff --git a/tests/shell/testcases/listing/0020flowtable_0 b/tests/shell/testcases/listing/0020flowtable_0
index 6f630f14..2f0a98d1 100755
--- a/tests/shell/testcases/listing/0020flowtable_0
+++ b/tests/shell/testcases/listing/0020flowtable_0
@@ -15,7 +15,6 @@ $NFT -f - <<< "$EXPECTED"
 
 GET="$($NFT list flowtable inet filter f)"
 if [ "$EXPECTED" != "$GET" ] ; then
-	DIFF="$(which diff)"
-	[ -x $DIFF ] && $DIFF -u <(echo "$EXPECTED") <(echo "$GET")
+	$DIFF -u <(echo "$EXPECTED") <(echo "$GET")
 	exit 1
 fi
diff --git a/tests/shell/testcases/maps/0003map_add_many_elements_0 b/tests/shell/testcases/maps/0003map_add_many_elements_0
index 047f9497..2b254c51 100755
--- a/tests/shell/testcases/maps/0003map_add_many_elements_0
+++ b/tests/shell/testcases/maps/0003map_add_many_elements_0
@@ -61,8 +61,7 @@ EXPECTED="table ip x {
 }"
 GET=$($NFT list ruleset)
 if [ "$EXPECTED" != "$GET" ] ; then
-	DIFF="$(which diff)"
-	[ -x $DIFF ] && $DIFF -u <(echo "$EXPECTED") <(echo "$GET")
+	$DIFF -u <(echo "$EXPECTED") <(echo "$GET")
 	exit 1
 fi
 
diff --git a/tests/shell/testcases/maps/0004interval_map_create_once_0 b/tests/shell/testcases/maps/0004interval_map_create_once_0
index 58b399c1..3de0c9de 100755
--- a/tests/shell/testcases/maps/0004interval_map_create_once_0
+++ b/tests/shell/testcases/maps/0004interval_map_create_once_0
@@ -60,8 +60,7 @@ EXPECTED="table ip x {
 }"
 GET=$($NFT list ruleset)
 if [ "$EXPECTED" != "$GET" ] ; then
-	DIFF="$(which diff)"
-	[ -x $DIFF ] && $DIFF -u <(echo "$EXPECTED") <(echo "$GET")
+	$DIFF -u <(echo "$EXPECTED") <(echo "$GET")
 	exit 1
 fi
 
diff --git a/tests/shell/testcases/maps/0008interval_map_delete_0 b/tests/shell/testcases/maps/0008interval_map_delete_0
index 7da6eb38..39ea3127 100755
--- a/tests/shell/testcases/maps/0008interval_map_delete_0
+++ b/tests/shell/testcases/maps/0008interval_map_delete_0
@@ -26,7 +26,6 @@ $NFT add element filter m { 127.0.0.2 : 0x2 }
 
 GET=$($NFT -s list ruleset)
 if [ "$EXPECTED" != "$GET" ] ; then
-	DIFF="$(which diff)"
-	[ -x $DIFF ] && $DIFF -u <(echo "$EXPECTED") <(echo "$GET")
+	$DIFF -u <(echo "$EXPECTED") <(echo "$GET")
 	exit 1
 fi
diff --git a/tests/shell/testcases/netns/0001nft-f_0 b/tests/shell/testcases/netns/0001nft-f_0
index 81942263..a591f2cd 100755
--- a/tests/shell/testcases/netns/0001nft-f_0
+++ b/tests/shell/testcases/netns/0001nft-f_0
@@ -93,8 +93,7 @@ fi
 KERNEL_RULESET="$($IP netns exec $NETNS_NAME $NFT list ruleset)"
 $IP netns del $NETNS_NAME
 if [ "$RULESET" != "$KERNEL_RULESET" ] ; then
-        DIFF="$(which diff)"
-        [ -x $DIFF ] && $DIFF -u <(echo "$RULESET") <(echo "$KERNEL_RULESET")
+        $DIFF -u <(echo "$RULESET") <(echo "$KERNEL_RULESET")
         exit 1
 fi
 exit 0
diff --git a/tests/shell/testcases/netns/0002loosecommands_0 b/tests/shell/testcases/netns/0002loosecommands_0
index 465c2e86..231f1fb7 100755
--- a/tests/shell/testcases/netns/0002loosecommands_0
+++ b/tests/shell/testcases/netns/0002loosecommands_0
@@ -56,7 +56,6 @@ RULESET="table ip t {
 KERNEL_RULESET="$($IP netns exec $NETNS_NAME $NFT list ruleset)"
 $IP netns del $NETNS_NAME
 if [ "$RULESET" != "$KERNEL_RULESET" ] ; then
-        DIFF="$(which diff)"
-        [ -x $DIFF ] && $DIFF -u <(echo "$RULESET") <(echo "$KERNEL_RULESET")
+        $DIFF -u <(echo "$RULESET") <(echo "$KERNEL_RULESET")
         exit 1
 fi
diff --git a/tests/shell/testcases/netns/0003many_0 b/tests/shell/testcases/netns/0003many_0
index a5fcb5d6..afe9117d 100755
--- a/tests/shell/testcases/netns/0003many_0
+++ b/tests/shell/testcases/netns/0003many_0
@@ -97,8 +97,7 @@ function test_netns()
 	KERNEL_RULESET="$($IP netns exec $NETNS_NAME $NFT list ruleset)"
 	if [ "$RULESET" != "$KERNEL_RULESET" ] ; then
 		echo "E: ruleset in netns $NETNS_NAME differs from the loaded" >&2
-	        DIFF="$(which diff)"
-	        [ -x $DIFF ] && $DIFF -u <(echo "$RULESET") <(echo "$KERNEL_RULESET")
+	        $DIFF -u <(echo "$RULESET") <(echo "$KERNEL_RULESET")
 		$IP netns del $NETNS_NAME
 	        exit 1
 	fi
diff --git a/tests/shell/testcases/nft-f/0016redefines_1 b/tests/shell/testcases/nft-f/0016redefines_1
index 4c26b379..1f59f6b8 100755
--- a/tests/shell/testcases/nft-f/0016redefines_1
+++ b/tests/shell/testcases/nft-f/0016redefines_1
@@ -26,8 +26,7 @@ $NFT -f - <<< "$RULESET"
 GET="$($NFT list ruleset)"
 
 if [ "$EXPECTED" != "$GET" ] ; then
-        DIFF="$(which diff)"
-        [ -x $DIFF ] && $DIFF -u <(echo "$EXPECTED") <(echo "$GET")
+        $DIFF -u <(echo "$EXPECTED") <(echo "$GET")
         exit 1
 fi
 
diff --git a/tests/shell/testcases/optionals/delete_object_handles_0 b/tests/shell/testcases/optionals/delete_object_handles_0
index a2ae4228..9b65e677 100755
--- a/tests/shell/testcases/optionals/delete_object_handles_0
+++ b/tests/shell/testcases/optionals/delete_object_handles_0
@@ -37,7 +37,6 @@ table ip6 test-ip6 {
 GET="$($NFT list ruleset)"
 
 if [ "$EXPECTED" != "$GET" ] ; then
-	DIFF="$(which diff)"
-	[ -x $DIFF ] && $DIFF -u <(echo "$EXPECTED") <(echo "$GET")
+	$DIFF -u <(echo "$EXPECTED") <(echo "$GET")
 	exit 1
 fi
diff --git a/tests/shell/testcases/optionals/update_object_handles_0 b/tests/shell/testcases/optionals/update_object_handles_0
index 17c0c86c..8b12b8c5 100755
--- a/tests/shell/testcases/optionals/update_object_handles_0
+++ b/tests/shell/testcases/optionals/update_object_handles_0
@@ -19,7 +19,6 @@ EXPECTED="table ip test-ip {
 
 GET="$($NFT list ruleset)"
 if [ "$EXPECTED" != "$GET" ] ; then
-	DIFF="$(which diff)"
-	[ -x $DIFF ] && $DIFF -u <(echo "$EXPECTED") <(echo "$GET")
+	$DIFF -u <(echo "$EXPECTED") <(echo "$GET")
 	exit 1
 fi
diff --git a/tests/shell/testcases/rule_management/0001addinsertposition_0 b/tests/shell/testcases/rule_management/0001addinsertposition_0
index bb3fda51..237e9e32 100755
--- a/tests/shell/testcases/rule_management/0001addinsertposition_0
+++ b/tests/shell/testcases/rule_management/0001addinsertposition_0
@@ -30,8 +30,7 @@ for arg in "position 2" "handle 2" "index 0"; do
 
 	GET="$($NFT list ruleset)"
 	if [ "$EXPECTED" != "$GET" ] ; then
-		DIFF="$(which diff)"
-		[ -x $DIFF ] && $DIFF -u <(echo "$EXPECTED") <(echo "$GET")
+		$DIFF -u <(echo "$EXPECTED") <(echo "$GET")
 		exit 1
 	fi
 done
@@ -42,8 +41,7 @@ for arg in "position 3" "handle 3" "index 1"; do
 
 	GET="$($NFT list ruleset)"
 	if [ "$EXPECTED" != "$GET" ] ; then
-		DIFF="$(which diff)"
-		[ -x $DIFF ] && $DIFF -u <(echo "$EXPECTED") <(echo "$GET")
+		$DIFF -u <(echo "$EXPECTED") <(echo "$GET")
 		exit 1
 	fi
 done
@@ -62,8 +60,7 @@ for arg in "position 3" "handle 3" "index 1"; do
 
 	GET="$($NFT list ruleset)"
 	if [ "$EXPECTED" != "$GET" ] ; then
-		DIFF="$(which diff)"
-		[ -x $DIFF ] && $DIFF -u <(echo "$EXPECTED") <(echo "$GET")
+		$DIFF -u <(echo "$EXPECTED") <(echo "$GET")
 		exit 1
 	fi
 done
@@ -82,8 +79,7 @@ for arg in "position 2" "handle 2" "index 0"; do
 
 	GET="$($NFT list ruleset)"
 	if [ "$EXPECTED" != "$GET" ] ; then
-		DIFF="$(which diff)"
-		[ -x $DIFF ] && $DIFF -u <(echo "$EXPECTED") <(echo "$GET")
+		$DIFF -u <(echo "$EXPECTED") <(echo "$GET")
 		exit 1
 	fi
 done
diff --git a/tests/shell/testcases/sets/0028delete_handle_0 b/tests/shell/testcases/sets/0028delete_handle_0
index 5ad17c22..c6d12534 100755
--- a/tests/shell/testcases/sets/0028delete_handle_0
+++ b/tests/shell/testcases/sets/0028delete_handle_0
@@ -29,7 +29,6 @@ EXPECTED="table ip test-ip {
 GET="$($NFT list ruleset)"
 
 if [ "$EXPECTED" != "$GET" ] ; then
-	DIFF="$(which diff)"
-	[ -x $DIFF ] && $DIFF -u <(echo "$EXPECTED") <(echo "$GET")
+	$DIFF -u <(echo "$EXPECTED") <(echo "$GET")
 	exit 1
 fi
diff --git a/tests/shell/testcases/sets/0036add_set_element_expiration_0 b/tests/shell/testcases/sets/0036add_set_element_expiration_0
index 8dfed6c1..51ed0f2c 100755
--- a/tests/shell/testcases/sets/0036add_set_element_expiration_0
+++ b/tests/shell/testcases/sets/0036add_set_element_expiration_0
@@ -8,6 +8,9 @@ add element ip x y { 1.1.1.1 timeout 30s expires 15s }"
 
 test_output=$($NFT -e -f - <<< "$RULESET" 2>&1)
 
-diff -u <(echo "$test_output") <(echo "$RULESET")
+if [ "$test_output" != "$RULESET" ] ; then
+	$DIFF -u <(echo "$test_output") <(echo "$RULESET")
+	exit 1
+fi
 
 $NFT "add chain ip x c; add rule ip x c ip saddr @y"
diff --git a/tests/shell/testcases/transactions/0003table_0 b/tests/shell/testcases/transactions/0003table_0
index 6861eaba..91186dec 100755
--- a/tests/shell/testcases/transactions/0003table_0
+++ b/tests/shell/testcases/transactions/0003table_0
@@ -14,7 +14,6 @@ fi
 
 KERNEL_RULESET="$($NFT list ruleset)"
 if [ "" != "$KERNEL_RULESET" ] ; then
-	DIFF="$(which diff)"
 	echo "Got a ruleset, but expected empty: "
 	echo "$KERNEL_RULESET"
 	exit 1
@@ -42,7 +41,6 @@ $NFT -f - <<< "$RULESETFAIL" && exit 2
 
 KERNEL_RULESET="$($NFT list ruleset)"
 if [ "$RULESET" != "$KERNEL_RULESET" ] ; then
-        DIFF="$(which diff)"
-        [ -x $DIFF ] && $DIFF -u <(echo "$RULESET") <(echo "$KERNEL_RULESET")
+        $DIFF -u <(echo "$RULESET") <(echo "$KERNEL_RULESET")
         exit 1
 fi
diff --git a/tests/shell/testcases/transactions/0040set_0 b/tests/shell/testcases/transactions/0040set_0
index a404abc8..468816b0 100755
--- a/tests/shell/testcases/transactions/0040set_0
+++ b/tests/shell/testcases/transactions/0040set_0
@@ -29,8 +29,7 @@ fi
 GET="$($NFT list ruleset)"
 
 if [ "$RULESET" != "$GET" ] ; then
-	DIFF="$(which diff)"
-	[ -x $DIFF ] && $DIFF -u <(echo "$RULESET") <(echo "$GET")
+	$DIFF -u <(echo "$RULESET") <(echo "$GET")
 	exit 1
 fi