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/docker-compose.yml

@@ -9,9 +9,9 @@ services:
     volumes:
       - postgres_data:/var/lib/postgresql/data
     environment:
-      - POSTGRES_PASSWORD=1FHJMSwt0yhIN1zS7I4DilGUhThBKq0x
-      - POSTGRES_USER=test
-      - POSTGRES_DB=test
+      POSTGRES_PASSWORD: 1FHJMSwt0yhIN1zS7I4DilGUhThBKq0x
+      POSTGRES_USER: test
+      POSTGRES_DB: test
 
   backup:
     image: offen/docker-volume-backup:${TEST_VERSION}
@@ -21,7 +21,7 @@ services:
     volumes:
       - postgres_data:/backup/postgres:ro
       - /var/run/docker.sock:/var/run/docker.sock:ro
-      - ./local:/archive
+      - ${LOCAL_DIR:-./local}:/archive
 
 volumes:
   postgres_data: