Expose test artifacts to the Gitlab CI interface

Make tests generate JUnit artifacts and expose them to the Gitlab CI UI.

test/integration-test.yml

@@ -30,14 +30,14 @@
       slurp:
         src: "/artifacts/pytest.xml"
       register: pytest_xml
-      when: "pytest_xml_stat and pytest_xml_stat.exists"
+      when: "pytest_xml_stat.exists | default(False)"
 
     - name: Store test results locally
       local_action:
         module: copy
         dest: "pytest.xml"
         content: "{{ pytest_xml['content'] | b64decode }}"
-      when: "pytest_xml_stat and pytest_xml_stat.exists"
+      when: "pytest_xml_stat.exists | default(False)"
 
   vars:
     test_image: "registry.git.autistici.org/ai3/float:integration-test"