Add dependency-aware module ordering

tests/common/test_command.py

@@ -4,11 +4,59 @@
 #   https://license.mvt.re/1.1/
 
 import json
+import logging
 
 from mvt.common.command import Command
+from mvt.common.module import MVTModule
+
+
+class RecordingModule(MVTModule):
+    run_order = []
+
+    def run(self):
+        self.run_order.append(self.__class__.__name__)
+
+    def check_indicators(self):
+        pass
+
+
+class FirstModule(RecordingModule):
+    def run(self):
+        super().run()
+        self.results = ["first"]
+
+
+class SecondModule(RecordingModule):
+    dependencies = (FirstModule,)
+
+    def run(self):
+        super().run()
+        self.results = self.get_dependency_results(FirstModule) + ["second"]
+
+
+class ThirdModule(RecordingModule):
+    dependencies = (SecondModule,)
+
+
+class IndependentModule(RecordingModule):
+    pass
+
+
+class RecordingCommand(Command):
+    def init(self):
+        self.initialized = True
+
+    def module_init(self, module):
+        pass
+
+    def finish(self):
+        pass
 
 
 class TestCommand:
+    def setup_method(self):
+        RecordingModule.run_order = []
+
     def test_store_alerts_handles_bytes(self, tmp_path):
         cmd = Command(results_path=str(tmp_path))
         cmd.alertstore.medium(
@@ -21,3 +69,66 @@ class TestCommand:
 
         alerts = json.loads((tmp_path / "alerts.json").read_text())
         assert alerts[0]["event"]["payload"] == "\\xa8\\xa9"
+
+    def test_modules_run_in_stable_topological_order(self):
+        cmd = RecordingCommand()
+        cmd.modules = [ThirdModule, IndependentModule, SecondModule, FirstModule]
+
+        cmd.run()
+
+        assert RecordingModule.run_order == [
+            "IndependentModule",
+            "FirstModule",
+            "SecondModule",
+            "ThirdModule",
+        ]
+        second = next(module for module in cmd.executed if isinstance(module, SecondModule))
+        assert second.results == ["first", "second"]
+
+    def test_selected_module_runs_transitive_dependencies(self):
+        cmd = RecordingCommand(module_name="ThirdModule")
+        cmd.modules = [ThirdModule, SecondModule, FirstModule, IndependentModule]
+
+        cmd.run()
+
+        assert RecordingModule.run_order == [
+            "FirstModule",
+            "SecondModule",
+            "ThirdModule",
+        ]
+
+    def test_circular_dependency_warns_and_stops(self, caplog):
+        class CircularOne(RecordingModule):
+            pass
+
+        class CircularTwo(RecordingModule):
+            dependencies = (CircularOne,)
+
+        CircularOne.dependencies = (CircularTwo,)
+
+        cmd = RecordingCommand()
+        cmd.modules = [CircularOne, CircularTwo]
+
+        with caplog.at_level(logging.WARNING):
+            cmd.run()
+
+        assert RecordingModule.run_order == []
+        assert not hasattr(cmd, "initialized")
+        assert "Circular module dependency detected" in caplog.text
+
+    def test_unavailable_dependency_warns_and_stops(self, caplog):
+        class UnavailableModule(RecordingModule):
+            pass
+
+        class DependentModule(RecordingModule):
+            dependencies = (UnavailableModule,)
+
+        cmd = RecordingCommand()
+        cmd.modules = [DependentModule]
+
+        with caplog.at_level(logging.WARNING):
+            cmd.run()
+
+        assert RecordingModule.run_order == []
+        assert not hasattr(cmd, "initialized")
+        assert "depends on unavailable module UnavailableModule" in caplog.text