tests: Determine initial version from filename

Makefile

@@ -1,10 +1,6 @@
 MICROOVN_SNAP=microovn.snap
 export MICROOVN_SNAP_PATH := $(CURDIR)/$(MICROOVN_SNAP)
 
-ifndef MICROOVN_SNAP_CHANNEL
-	export MICROOVN_SNAP_CHANNEL="22.03/stable"
-endif
-
 .DEFAULT_GOAL := $(MICROOVN_SNAP)
 
 ALL_TESTS := $(wildcard tests/*.bats)

tests/test_helper/bats/ovsdb_schema_upgrade.bats

@@ -1,5 +1,9 @@
 # This is a bash shell fragment -*- bash -*-
 
+# Define test filename prefix that helps to determine from which version should
+# the upgrade be tested.
+export TEST_NAME_PREFIX="ovsdb_schema_upgrade"
+
 load "test_helper/setup_teardown/$(basename "${BATS_TEST_FILENAME//.bats/.bash}")"
 
 setup() {

tests/test_helper/bats/upgrade.bats

@@ -1,5 +1,9 @@
 # This is a bash shell fragment -*- bash -*-
 
+# Define test filename prefix that helps to determine from which version should
+# the upgrade be tested.
+export TEST_NAME_PREFIX="upgrade"
+
 # Instruct the ``setup_file`` function to perform the upgrade.
 export UPGRADE_DO_UPGRADE=1
 load "test_helper/setup_teardown/$(basename "${BATS_TEST_FILENAME//.bats/.bash}")"

tests/test_helper/common.bash

@@ -138,3 +138,43 @@ function test_snap_is_stable_base() {
 
     [ "$version_info" != "--" ]
 }
+
+
+# get_upgrade_test_version TEST_FILE_NAME TEST_PREFIX
+#
+# Parse test filename of an "upgrade" test to determine which version should the
+# test upgrade from.
+#
+# MicroOVN upgrade tests need to define initial MicroOVN version to be deployed, so that
+# the tests can verify if the upgrade is possible. Initial version is defined in filename.
+#
+# For example, by passing "upgrade_22.03.bats" TEST_FILE_NAME and "upgrade" TEST_PREFIX into
+# this function, it returns "22.03/stable".
+#
+# If there's no version defined in the test filename, (e.g. TEST_FILE_NAME is "upgrade.bats"
+# and TEST_PREFIX is "upgrade"), an empty string is returned.
+#
+# If filename does not match expected formats "<TEST_PREFIX>_<MAJOR_VERSION>.<MINOR_VERSION>.bats",
+# or "<TEST_PREFIX>.bats", this function returns with error code.
+function get_upgrade_test_version() {
+    local test_name=$1; shift
+    local test_prefix=$1; shift
+
+    upgrade_from_version=""
+
+    if [ "$test_name" != "${test_prefix}.bats" ]; then
+        upgrade_from_version=$(sed -nr 's/^'"$test_prefix"'_([0-9]+\.[0-9]+)\.bats/\1/p' <<< "$test_name")
+
+        if [ -z "$upgrade_from_version" ]; then
+            echo "Failed to determine MicroOVN upgrade version for this test: '$test_name'." >&2
+            echo "" >&2
+            echo "Expected test name is '${test_prefix}_<major_version>.<minor_version>.bats'" >&2
+            echo "where '<major_version>.<minor_version>' determine MicroOVN track from which" >&2
+            echo "the test will be performed." >&2
+            exit 1
+        fi
+
+        upgrade_from_version="${upgrade_from_version}/stable"
+    fi
+    echo "$upgrade_from_version"
+}

tests/test_helper/microovn.bash

@@ -45,14 +45,21 @@ function install_microovn() {
 
 # install_microovn_from_store CHANNEL CONTAINER1 [CONTAINER2 ...]
 #
-# Install MicroOVN snap from specified CHANNEL from Snap store in all CONTAINERs.
+# Install MicroOVN snap from specified CHANNEL from Snap store in all CONTAINERs. If
+# the CHANNEL argument is an empty string, a default channel will be used.
 function install_microovn_from_store() {
     local channel=$1; shift
     local containers=$*
+    local source_channel=""
+    local channel_pretty_name="default"
 
+    if [ -n "$channel" ]; then
+        channel_pretty_name="$channel"
+        source_channel="--channel $channel"
+    fi
     for container in $containers; do
-        echo "# Installing MicroOVN from SnapStore in container $container" >&3
-        lxc_exec "$container" "snap install microovn --channel $channel"
+        echo "# Installing MicroOVN from SnapStore ('$channel_pretty_name' channel) in container $container" >&3
+        lxc_exec "$container" "snap install microovn $source_channel"
     done
 }
 

tests/test_helper/setup_teardown/upgrade.bash

@@ -9,10 +9,11 @@ setup_file() {
     ABS_TOP_TEST_DIRNAME="${BATS_TEST_DIRNAME}/"
     export ABS_TOP_TEST_DIRNAME
 
-    # Env variable MICROOVN_SNAP_CHANNEL must be specified for tests to know
-    # from which channel should be MicroOVN installed before upgrading
-    assert [ -n "$MICROOVN_SNAP_CHANNEL" ]
+    # Determine MicroOVN channel from which we are upgrading
+    test_name=$(basename "$BATS_TEST_FILENAME")
+    MICROOVN_SNAP_CHANNEL=$(get_upgrade_test_version "$test_name" "$TEST_NAME_PREFIX")
 
+    # Create test deployment
     TEST_CONTAINERS=$(container_names "$BATS_TEST_FILENAME" 4)
     CENTRAL_CONTAINERS=""
     CHASSIS_CONTAINERS=""