diff --git a/tests/ebuild/test_dispatch.py b/tests/ebuild/test_dispatch.py
index d4d75f7..fb64bb2 100644
--- a/tests/ebuild/test_dispatch.py
+++ b/tests/ebuild/test_dispatch.py
@@ -204,6 +204,7 @@ def test_configure_ninja_raises_instead_of_silently_passing(self, tmp_path):
         d = BackendDispatcher(tmp_path, tmp_path / "build")
         with pytest.raises(UnknownBackendError, match="ninja"):
             d.configure("ninja")
+        assert not (tmp_path / "build").exists()
 
     def test_ninja_error_explains_the_targets_requirement(self, tmp_path):
         """The message must be actionable, not just a rejection."""
@@ -227,8 +228,10 @@ def test_clean_still_accepts_ninja(self, tmp_path):
         d = BackendDispatcher(tmp_path, tmp_path / "build")
         d.clean("ninja", dry_run=True)  # must not raise
 
-    def test_no_configure_step_backends_stay_noops(self, tmp_path):
+    @patch("ebuild.build.dispatch.subprocess")
+    def test_no_configure_step_backends_stay_noops(self, mock_sub, tmp_path):
         """cargo/make/kbuild are accepted-and-skipped, not errors."""
         d = BackendDispatcher(tmp_path, tmp_path / "build")
         for backend in ("cargo", "make", "kbuild"):
-            d.configure(backend)  # must not raise
+            d.configure(backend)
+        mock_sub.run.assert_not_called()