tests/shell: cleanup creating dummy interfaces in tests

In "tests/shell/testcases/chains/netdev_chain_0", calling "trap ...
EXIT" multiple times does not work. Fix it, by calling one cleanup
function.

Note that we run in separate namespaces, so the cleanup is usually not
necessary. Still do it, we might want to run without unshare (via
NFT_TEST_UNSHARE_CMD=""). Without unshare, it's important that the
cleanup always works. In practice it might not, for example, "trap ...
EXIT" does not run for SIGTERM. A leaked interface might break the
follow up test and tests interfere with each other.

Try to workaround that by first trying to delete the interface.

Also failures to create the interfaces are not considered fatal. I don't
understand under what circumstances this might fail, note that there are
other tests that create dummy interface and don't "exit 77" on failure.
We want to know when something odd is going on.

Signed-off-by: Thomas Haller <thaller@redhat.com>
Signed-off-by: Florian Westphal <fw@strlen.de>

2 files changed, 8 insertions, 2 deletions

diff --git a/tests/shell/testcases/flowtable/0012flowtable_variable_0 b/tests/shell/testcases/flowtable/0012flowtable_variable_0
index 8e334224..080059d2 100755
--- a/tests/shell/testcases/flowtable/0012flowtable_variable_0
+++ b/tests/shell/testcases/flowtable/0012flowtable_variable_0
@@ -2,6 +2,12 @@
 
 set -e
 
+iface_cleanup() {
+	ip link del dummy1 &>/dev/null || :
+}
+trap 'iface_cleanup' EXIT
+iface_cleanup
+
 ip link add name dummy1 type dummy
 
 EXPECTED="define if_main = { lo, dummy1 }
diff --git a/tests/shell/testcases/flowtable/dumps/0012flowtable_variable_0.nft b/tests/shell/testcases/flowtable/dumps/0012flowtable_variable_0.nft
index 1cbb2f11..df1c51a2 100644
--- a/tests/shell/testcases/flowtable/dumps/0012flowtable_variable_0.nft
+++ b/tests/shell/testcases/flowtable/dumps/0012flowtable_variable_0.nft
@@ -1,14 +1,14 @@
 table ip filter1 {
 	flowtable Main_ft1 {
 		hook ingress priority filter
-		devices = { dummy1, lo }
+		devices = { lo }
 		counter
 	}
 }
 table ip filter2 {
 	flowtable Main_ft2 {
 		hook ingress priority filter
-		devices = { dummy1, lo }
+		devices = { lo }
 		counter
 	}
 }