DEVX-67: refactor: make molecule weights configurable via pyproject.toml

tests/unit/test_distribute_molecule.py

@@ -13,6 +13,7 @@ from devx.molecule.distribute_molecule import (
     PLATFORMS,
     MultiRoleTestPair,
     TestPair,
+    _load_molecule_weights,
     _lpt_distribute,
     _scenario_weight,
     build_multi_role_pairs,
@@ -482,42 +483,90 @@ class TestCliMultiRole:
 
 
 class TestScenarioWeight:
-    def test_known_heavy_scenario(self) -> None:
-        assert _scenario_weight("nextcloud") == 15
-        assert _scenario_weight("gitea") == 8
-
-    def test_known_light_scenario(self) -> None:
-        assert _scenario_weight("binary") == 2
-
-    def test_default_weight(self) -> None:
+    def test_default_weight_no_config(self, tmp_path: Path, monkeypatch: pytest.MonkeyPatch) -> None:
+        """Without pyproject.toml, all scenarios get the default weight."""
+        monkeypatch.chdir(tmp_path)
+        scenario_w, role_w = _load_molecule_weights()
+        assert scenario_w == {}
+        assert role_w == {}
         assert _scenario_weight("unknown-scenario") == 3
 
-    def test_case_insensitive(self) -> None:
-        assert _scenario_weight("NextCloud") == 15
-        assert _scenario_weight("GITEA") == 8
+    def test_load_weights_from_pyproject(self, tmp_path: Path) -> None:
+        """Weights are loaded from [tool.devx.molecule.weights] in pyproject.toml."""
+        pyproject = tmp_path / "pyproject.toml"
+        pyproject.write_text(
+            "[tool.devx.molecule.weights]\n"
+            '"nextcloud" = 15\n'
+            '"default" = 3\n'
+            '"binary" = 2\n'
+            '"app_container/customer-apps" = 11\n'
+            '"restore/default" = 11\n'
+        )
+        scenario_w, role_w = _load_molecule_weights(str(pyproject))
+        assert scenario_w == {"nextcloud": 15, "default": 3, "binary": 2}
+        assert role_w == {("app_container", "customer-apps"): 11, ("restore", "default"): 11}
 
-    def test_substring_match(self) -> None:
-        assert _scenario_weight("nextcloud-with-redis") == 15
-        assert _scenario_weight("custom-gitea-setup") == 8
-
-    def test_role_specific_weight(self) -> None:
-        """Role+scenario pairs take priority over scenario-name-only weights."""
-        assert _scenario_weight("default", "restore") == 11
-        assert _scenario_weight("default", "zitadel") == 10
+    def test_role_specific_takes_priority(self, tmp_path: Path, monkeypatch: pytest.MonkeyPatch) -> None:
+        """Role-specific weights take priority over scenario-name-only weights."""
+        pyproject = tmp_path / "pyproject.toml"
+        pyproject.write_text(
+            '[tool.devx.molecule.weights]\n"default" = 3\n"docker_base/default" = 8\n"restore/default" = 11\n'
+        )
+        scenario_w, role_w = _load_molecule_weights(str(pyproject))
+        monkeypatch.setattr("devx.molecule.distribute_molecule._SCENARIO_WEIGHTS", scenario_w)
+        monkeypatch.setattr("devx.molecule.distribute_molecule._ROLE_SCENARIO_WEIGHTS", role_w)
         assert _scenario_weight("default", "docker_base") == 8
-        assert _scenario_weight("default", "app_hardening") == 4
+        assert _scenario_weight("default", "restore") == 11
         assert _scenario_weight("default", "app_container") == 3
-        assert _scenario_weight("default", "storage") == 3
-        assert _scenario_weight("default", "observability") == 3
 
-    def test_role_specific_overrides_scenario_name(self) -> None:
-        """vaultwarden has a scenario-name weight of 2, but role-specific is also 2."""
-        assert _scenario_weight("vaultwarden", "app_container") == 2
-        assert _scenario_weight("vaultwarden") == 2
+    def test_case_insensitive(self, tmp_path: Path, monkeypatch: pytest.MonkeyPatch) -> None:
+        """Weight keys are matched case-insensitively."""
+        pyproject = tmp_path / "pyproject.toml"
+        pyproject.write_text('[tool.devx.molecule.weights]\n"nextcloud" = 15\n')
+        scenario_w, role_w = _load_molecule_weights(str(pyproject))
+        monkeypatch.setattr("devx.molecule.distribute_molecule._SCENARIO_WEIGHTS", scenario_w)
+        monkeypatch.setattr("devx.molecule.distribute_molecule._ROLE_SCENARIO_WEIGHTS", role_w)
+        assert _scenario_weight("NextCloud") == 15
+        assert _scenario_weight("NEXTCLOUD") == 15
 
-    def test_customer_apps_weight(self) -> None:
-        assert _scenario_weight("customer-apps", "app_container") == 11
-        assert _scenario_weight("customer-apps") == 11
+    def test_substring_match(self, tmp_path: Path, monkeypatch: pytest.MonkeyPatch) -> None:
+        """Scenario-name weights use substring matching."""
+        pyproject = tmp_path / "pyproject.toml"
+        pyproject.write_text('[tool.devx.molecule.weights]\n"nextcloud" = 15\n')
+        scenario_w, role_w = _load_molecule_weights(str(pyproject))
+        monkeypatch.setattr("devx.molecule.distribute_molecule._SCENARIO_WEIGHTS", scenario_w)
+        monkeypatch.setattr("devx.molecule.distribute_molecule._ROLE_SCENARIO_WEIGHTS", role_w)
+        assert _scenario_weight("nextcloud-with-redis") == 15
+
+    def test_no_pyproject_returns_empty(self, tmp_path: Path) -> None:
+        """Missing pyproject.toml returns empty weight dicts."""
+        scenario_w, role_w = _load_molecule_weights(str(tmp_path / "nonexistent.toml"))
+        assert scenario_w == {}
+        assert role_w == {}
+
+    def test_invalid_weights_ignored(self, tmp_path: Path) -> None:
+        """Non-integer weight values are silently ignored."""
+        pyproject = tmp_path / "pyproject.toml"
+        pyproject.write_text('[tool.devx.molecule.weights]\n"good" = 5\n"bad" = "not an int"\n')
+        scenario_w, role_w = _load_molecule_weights(str(pyproject))
+        assert scenario_w == {"good": 5}
+        assert role_w == {}
+
+    def test_malformed_toml_returns_empty(self, tmp_path: Path) -> None:
+        """Malformed TOML returns empty weight dicts."""
+        pyproject = tmp_path / "pyproject.toml"
+        pyproject.write_text("this is not valid toml = = =")
+        scenario_w, role_w = _load_molecule_weights(str(pyproject))
+        assert scenario_w == {}
+        assert role_w == {}
+
+    def test_non_dict_weights_returns_empty(self, tmp_path: Path) -> None:
+        """If [tool.devx.molecule.weights] is not a table, returns empty dicts."""
+        pyproject = tmp_path / "pyproject.toml"
+        pyproject.write_text('[tool.devx.molecule]\nweights = "not a table"\n')
+        scenario_w, role_w = _load_molecule_weights(str(pyproject))
+        assert scenario_w == {}
+        assert role_w == {}
 
 
 class TestLptDistribute: