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/ownership/run.sh

@@ -7,24 +7,22 @@ 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
 
 docker compose exec backup backup
 
-tmp_dir=$(mktemp -d)
-sudo tar --same-owner -xvf ./local/backup.tar.gz -C $tmp_dir
+TMP_DIR=$(mktemp -d)
+tar --same-owner -xvf "$LOCAL_DIR/backup.tar.gz" -C $TMP_DIR
 
-sudo find $tmp_dir/backup/postgres > /dev/null
+find $TMP_DIR/backup/postgres > /dev/null
 pass "Backup contains files at expected location"
 
-for file in $(sudo find $tmp_dir/backup/postgres); do
-  if [ "$(sudo stat -c '%u:%g' $file)" != "70:70" ]; then
-    fail "Unexpected file ownership for $file: $(sudo stat -c '%u:%g' $file)"
+for file in $(find $TMP_DIR/backup/postgres); do
+  if [ "$(stat -c '%u:%g' $file)" != "70:70" ]; then
+    fail "Unexpected file ownership for $file: $(stat -c '%u:%g' $file)"
   fi
 done
 pass "All files and directories in backup preserved their ownership."
-
-docker compose down --volumes