test: add a script for supporting multi-dev and multi-stage case

conftest.py

@@ -33,6 +33,12 @@ from pytest_embedded.plugin import multi_dut_argument, multi_dut_fixture
 from pytest_embedded.utils import find_by_suffix
 from pytest_embedded_idf.dut import IdfDut
 
+try:
+    from tools.ci.idf_unity_tester import CaseTester
+except ImportError:
+    sys.path.append(os.path.join(os.path.dirname(__file__), 'tools', 'ci'))
+    from idf_unity_tester import CaseTester
+
 try:
     import common_test_methods  # noqa: F401
 except ImportError:
@@ -118,6 +124,11 @@ def log_minimum_free_heap_size(dut: IdfDut, config: str) -> Callable[..., None]:
     return real_func
 
 
+@pytest.fixture
+def case_tester(dut: IdfDut, **kwargs):      # type: ignore
+    yield CaseTester(dut, **kwargs)
+
+
 @pytest.fixture
 @multi_dut_argument
 def config(request: FixtureRequest) -> str: