Implement systemd plugin

tests/test_decman_plugins.py

@@ -0,0 +1,26 @@
+from decman.core.module import Module
+from decman.plugins import run_method_with_attribute
+
+
+def mark(attr):
+    attr.__flag__ = True
+    return attr
+
+
+def test_runs_marked_method_and_returns_value():
+    class M(Module):
+        @mark
+        def foo(self):
+            return 123
+
+    m = M("m")
+    assert run_method_with_attribute(m, "__flag__") == 123
+
+
+def test_returns_none_if_no_method_has_attribute():
+    class M(Module):
+        def foo(self):
+            return 1
+
+    m = M("m")
+    assert run_method_with_attribute(m, "__flag__") is None