fix: merge integration tests into single file

tests/integration/test_charm.py

@@ -88,3 +88,43 @@ async def test_build_and_deploy(ops_test: OpsTest, charm, test_charm):
         "openfga-requires", "0", ops_test.model.units
     )
     assert "running with store" in openfga_requires_unit.workload_status_message
+
+
+@pytest.mark.abort_on_fail
+async def test_upgrade_running_application(ops_test: OpsTest, charm):
+    """Deploy latest published charm and upgrade it with charm-under-test.
+
+    Assert on the application status and health check endpoint after upgrade/refresh took place.
+    """
+    # Starting upgrade/refresh
+    logger.debug("starting upgrade test")
+
+    # Build and deploy charm from local source folder
+    logger.debug("building local charm")
+
+    charm = await ops_test.build_charm(".")
+    resources = {"openfga-image": METADATA["resources"]["openfga-image"]["upstream-source"]}
+
+    # Deploy the charm and wait for active/idle status
+    logger.debug("refreshing running application with the new local charm")
+
+    await ops_test.model.applications[APP_NAME].refresh(
+        path=charm,
+        resources=resources,
+    )
+
+    async with ops_test.fast_forward():
+        await ops_test.model.wait_for_idle(
+            apps=[APP_NAME],
+            status="active",
+            timeout=60,
+        )
+
+    assert ops_test.model.applications[APP_NAME].status == "active"
+
+    upgraded_openfga_unit = await utils.get_unit_by_name(APP_NAME, "0", ops_test.model.units)
+
+    health = await upgraded_openfga_unit.run("curl -s http://localhost:8080/healthz")
+    await health.wait()
+    assert health.results.get("return-code") == 0
+    assert health.results.get("stdout").strip() == '{"status":"SERVING"}'