Add custom module loading

tests/common/test_module_loader.py

@@ -0,0 +1,145 @@
+import pytest
+
+from mvt.common.module import MVTModule
+from mvt.common.module_loader import (
+    CustomModuleLoadError,
+    load_custom_modules,
+    load_custom_modules_from_path,
+    module_supports_command,
+)
+
+
+MODULE_TEMPLATE = """
+from mvt.common.module import MVTModule
+
+
+class {name}(MVTModule):
+    supported_commands = {supported_commands!r}
+
+    def run(self):
+        pass
+
+    def check_indicators(self):
+        pass
+
+    def serialize(self, result):
+        return None
+"""
+
+
+def _write_module(path, name, supported_commands=()):
+    path.write_text(
+        MODULE_TEMPLATE.format(
+            name=name,
+            supported_commands=supported_commands,
+        ),
+        encoding="utf-8",
+    )
+    return path
+
+
+def test_load_custom_modules_from_python_file(tmp_path):
+    module_path = _write_module(tmp_path / "custom.py", "FileModule")
+
+    modules = load_custom_modules_from_path(str(module_path))
+
+    assert [module.__name__ for module in modules] == ["FileModule"]
+    assert issubclass(modules[0], MVTModule)
+
+
+def test_load_custom_modules_from_folder_in_sorted_order(tmp_path):
+    _write_module(tmp_path / "b_module.py", "BModule")
+    _write_module(tmp_path / "a_module.py", "AModule")
+    _write_module(tmp_path / ".hidden.py", "HiddenModule")
+    _write_module(tmp_path / "__init__.py", "InitModule")
+    nested = tmp_path / "nested"
+    nested.mkdir()
+    _write_module(nested / "nested_module.py", "NestedModule")
+
+    modules = load_custom_modules_from_path(str(tmp_path))
+
+    assert [module.__name__ for module in modules] == ["AModule", "BModule"]
+
+
+def test_discovery_ignores_imported_base_and_unrelated_classes(tmp_path):
+    module_path = tmp_path / "custom.py"
+    module_path.write_text(
+        """
+from mvt.common.module import MVTModule
+
+
+class Unrelated:
+    pass
+
+
+class DiscoveredModule(MVTModule):
+    def run(self):
+        pass
+
+    def check_indicators(self):
+        pass
+
+    def serialize(self, result):
+        return None
+""",
+        encoding="utf-8",
+    )
+
+    modules = load_custom_modules_from_path(str(module_path))
+
+    assert [module.__name__ for module in modules] == ["DiscoveredModule"]
+
+
+def test_load_custom_modules_deduplicates_same_class(tmp_path):
+    module_path = _write_module(tmp_path / "custom.py", "DuplicateModule")
+
+    modules = load_custom_modules([str(module_path), str(module_path)])
+
+    assert [module.__name__ for module in modules] == ["DuplicateModule"]
+
+
+def test_load_custom_modules_raises_for_missing_path(tmp_path):
+    with pytest.raises(CustomModuleLoadError, match="does not exist"):
+        load_custom_modules_from_path(str(tmp_path / "missing.py"))
+
+
+def test_load_custom_modules_raises_for_import_error(tmp_path):
+    module_path = tmp_path / "broken.py"
+    module_path.write_text("raise RuntimeError('broken import')", encoding="utf-8")
+
+    with pytest.raises(CustomModuleLoadError, match="broken import"):
+        load_custom_modules_from_path(str(module_path))
+
+
+def test_load_custom_modules_loads_env_folder_first(tmp_path, monkeypatch):
+    env_folder = tmp_path / "env"
+    env_folder.mkdir()
+    cli_folder = tmp_path / "cli"
+    cli_folder.mkdir()
+    _write_module(env_folder / "env_module.py", "EnvModule")
+    _write_module(cli_folder / "cli_module.py", "CliModule")
+    monkeypatch.setenv("MVT_CUSTOM_MODULES", str(env_folder))
+
+    modules = load_custom_modules([str(cli_folder)])
+
+    assert [module.__name__ for module in modules] == ["EnvModule", "CliModule"]
+
+
+def test_module_supports_command_defaults_to_all_commands(tmp_path):
+    module_path = _write_module(tmp_path / "custom.py", "DefaultModule")
+    module = load_custom_modules_from_path(str(module_path))[0]
+
+    assert module_supports_command(module, "ios", "check-backup")
+    assert module_supports_command(module, "android", "check-bugreport")
+
+
+def test_module_supports_command_honors_supported_commands(tmp_path):
+    module_path = _write_module(
+        tmp_path / "custom.py",
+        "SpecificModule",
+        (("ios", "check-backup"),),
+    )
+    module = load_custom_modules_from_path(str(module_path))[0]
+
+    assert module_supports_command(module, "ios", "check-backup")
+    assert not module_supports_command(module, "ios", "check-fs")