Run tests Docker in Docker (#261)

* Try running tests in Docker

* Spawn new container for each test

* Store test artifacts outside of mount

* When requested, build up to date image in test script

* sudo is unneccessary in containerized test env

* Skip azure test

* Backdate fixture file in JSON database

* Pin versions for azure tools

* Mount temp volume for /var/lib/docker to prevent dangling ones created by VOLUME instruction

* Fail backdating tests with message

* Add some documentation on test setup

* Cache images

* Run compose stacks with shortened default timeout

test/notifications/.gitignore

@@ -1 +0,0 @@
-local

test/notifications/docker-compose.yml

@@ -12,7 +12,7 @@ services:
       NOTIFICATION_URLS: ${NOTIFICATION_URLS}
       EXTRA_VALUE: extra-value
     volumes:
-      - ./local:/archive
+      - ${LOCAL_DIR:-./local}:/archive
       - app_data:/backup/app_data:ro
       - ./notifications.tmpl:/etc/dockervolumebackup/notifications.d/notifications.tmpl
 

test/notifications/run.sh

@@ -6,7 +6,7 @@ cd $(dirname $0)
 . ../util.sh
 current_test=$(basename $(pwd))
 
-mkdir -p local
+export LOCAL_DIR=$(mktemp -d)
 
 docker compose up -d --quiet-pull
 sleep 5
@@ -46,5 +46,3 @@ if [ "$MESSAGE_BODY" != "Backing up /tmp/test.tar.gz succeeded." ]; then
   fail "Unexpected notification body $MESSAGE_BODY"
 fi
 pass "Custom notification body was used."
-
-docker compose down --volumes