diff --git a/tools/test_build_system/conftest.py b/tools/test_build_system/conftest.py
index a575cf5696..2236d4ca0a 100644
--- a/tools/test_build_system/conftest.py
+++ b/tools/test_build_system/conftest.py
@@ -120,6 +120,7 @@ def idf_copy(session_work_dir: Path, request: FixtureRequest) -> typing.Generato
     shutil.copytree(path_from, path_to, ignore=ignore, symlinks=True)
 
     orig_idf_path = os.environ['IDF_PATH']
+    os.environ['IDF_PATH'] = str(path_to)
 
     yield Path(path_to)
 
diff --git a/tools/test_build_system/test_build_system_helpers/idf_utils.py b/tools/test_build_system/test_build_system_helpers/idf_utils.py
index 96cc33db9a..8cc0e3fa7c 100644
--- a/tools/test_build_system/test_build_system_helpers/idf_utils.py
+++ b/tools/test_build_system/test_build_system_helpers/idf_utils.py
@@ -43,8 +43,11 @@ def get_idf_build_env(idf_path: str) -> EnvDict:
         '--format=key-value'
     ]
     keys_values = subprocess.check_output(cmd, stderr=subprocess.PIPE).decode()
-    env_vars = {key: os.path.expandvars(value) for key, value in
-                [line.split('=') for line in keys_values.splitlines()]}
+    idf_tool_py_env = {key: os.path.expandvars(value) for key, value in
+                       [line.split('=') for line in keys_values.splitlines()]}
+    env_vars = {}  # type: EnvDict
+    env_vars.update(os.environ)
+    env_vars.update(idf_tool_py_env)
     # not set by idf_tools.py, normally set by export.sh
     env_vars['IDF_PATH'] = idf_path