Dashboard minor refactor and first unit tests (#8705)

python/ray/tests/conftest.py

@@ -49,6 +49,13 @@ def _ray_start(**kwargs):
     ray.shutdown()
 
 
+@pytest.fixture
+def ray_start_with_dashboard(request):
+    param = getattr(request, "param", {})
+    with _ray_start(num_cpus=1, include_webui=True, **param) as address_info:
+        yield address_info
+
+
 # The following fixture will start ray with 0 cpu.
 @pytest.fixture
 def ray_start_no_cpu(request):