1 files changed, 3 insertions, 1 deletions
diff --git a/igor.py b/igor.py
index a1746351..6af3eb15 100644
--- a/igor.py
+++ b/igor.py
@@ -104,7 +104,9 @@ def run_tests(tracer, *runner_args):
     """The actual running of tests."""
     if 'COVERAGE_TESTING' not in os.environ:
         os.environ['COVERAGE_TESTING'] = "True"
-    os.environ['COVERAGE_ENV_ID'] = make_env_id(tracer)
+    # $set_env.py: COVERAGE_ENV_ID - Use environment-specific test directories.
+    if 'COVERAGE_ENV_ID' in os.environ:
+        os.environ['COVERAGE_ENV_ID'] = make_env_id(tracer)
     print_banner(label_for_tracer(tracer))
     return pytest.main(list(runner_args))