diff --git a/plan.fmf b/plan.fmf
index 827567e..c1a605f 100644
--- a/plan.fmf
+++ b/plan.fmf
@@ -21,8 +21,7 @@ discover:
     dist-git-download-only: true
     tests:
     - name: all_supplementing_pythons
-      path: /tests
-      test: ./all_supplementing_pythons.py
+      test: ./tests/all_supplementing_pythons.py
     - name: mock_with_tests
       # Needs cwd to contain downloaded sources, path to mocktes.sh depends on tmt tree structure
       test: |
diff --git a/tests/all_supplementing_pythons.py b/tests/all_supplementing_pythons.py
index 223bdf1..a473ae2 100755
--- a/tests/all_supplementing_pythons.py
+++ b/tests/all_supplementing_pythons.py
@@ -8,7 +8,7 @@ See https://lists.fedoraproject.org/archives/list/python-devel@lists.fedoraproje
 This script:
 
  1) figures out all packages in the enabled repositories supplementing tox
- 2) ensures there is a venv.sh test for each of them in tests.yml
+ 2) ensures there is a venv.sh test for each of them in plan.fmf
 
 That way, when we change tox (update, patch, etc.),
 we will always test it with all Pythons that supplement it.
@@ -34,16 +34,18 @@ def parse_python_test_arg(command):
 
 # First, construct a set of various Pythons we test, e.g. {python3.10, python3.7, pypy3.6, ...}
 tested_pythons = set()
-with open('tests.yml') as f:
-    tests_yml = yaml.safe_load(f)
+with open('plan.fmf') as f:
+    plan_fmf = yaml.safe_load(f)
 # this nested structure access is quite fragile,
 # but at least it should fail the test if we reach to a wrong place
-for test in tests_yml[-1]['roles'][0]['tests']:
-    for value in test.values():
-        run = value['run']
-        if run.endswith('./venv.sh'):
-            tested_pythons.add(parse_python_test_arg(run))
-print('Tested Pythons found in tests.yml:', file=sys.stderr)
+for discover_section in plan_fmf['discover']:
+    if discover_section['name'] != 'tests_python':
+        continue
+    for test in discover_section['tests']:
+        test_cmd = test['test']
+        if test_cmd.endswith('./venv.sh'):
+            tested_pythons.add(parse_python_test_arg(test_cmd))
+print('Tested Pythons found in plan.fmf:', file=sys.stderr)
 for python in sorted(tested_pythons):
     print('    ', python, file=sys.stderr)