add unit test for system usage

tests/supervisor/test_views.py

@@ -24,3 +24,16 @@ async def test_allocation_fails_on_invalid_item_hash(aiohttp_client):
             "type": "value_error.unknownhash",
         },
     ]
+
+
+@pytest.mark.asyncio
+async def test_system_usage(aiohttp_client):
+    """Test that the allocation endpoint fails when an invalid item_hash is provided."""
+    client = await aiohttp_client(app)
+    settings.ALLOCATION_TOKEN_HASH = "9f86d081884c7d659a2feaa0c55ad015a3bf4f1b2b0b822cd15d6c15b0f00a08"  # = "test"
+    response: web.Response = await client.get("/about/usage/system")
+    assert response.status == 200
+    # check if it is valid json
+    resp = await response.json()
+    assert "cpu" in resp
+    assert resp["cpu"]["count"] > 0