tests: skip boot loader check during testing preparation on s390x (#1…

…1423)

* Skip bootloader check during testing preparation on classic

As snapd does not care about the bootloader in classic systems, the idea
is to avoid this check to make the tests work on s390x architecture
where the bootloader is zipl.

* Skip bootloader check on s390x

tests/lib/prepare.sh

@@ -365,13 +365,16 @@ prepare_classic() {
 
         disable_refreshes
 
-        echo "Ensure that the bootloader environment output does not contain any of the snap_* variables on classic"
-        # shellcheck disable=SC2119
-        output=$("$TESTSTOOLS"/boot-state bootenv show)
-        if echo "$output" | MATCH snap_ ; then
-            echo "Expected bootloader environment without snap_*, got:"
-            echo "$output"
-            exit 1
+        # Check bootloader environment output in architectures different to s390x which uses zIPL
+        if ! [ "$(uname  -m)" = "s390x" ]; then
+            echo "Ensure that the bootloader environment output does not contain any of the snap_* variables on classic"
+            # shellcheck disable=SC2119
+            output=$("$TESTSTOOLS"/boot-state bootenv show)
+            if echo "$output" | MATCH snap_ ; then
+                echo "Expected bootloader environment without snap_*, got:"
+                echo "$output"
+                exit 1
+            fi
         fi
 
         setup_experimental_features