Add activate_async decorator (#48)

* Add activate_async decorator
* make activate_async python 3.4 compatible
* unify the import statement

pook/activate_async.py

@@ -0,0 +1,30 @@
+import functools
+from asyncio import iscoroutinefunction, coroutine
+
+
+def activate_async(fn, _engine):
+    """
+    Async version of activate decorator
+
+    Arguments:
+        fn (function): function that be wrapped by decorator.
+        _engine (Engine): pook engine instance
+
+    Returns:
+        function: decorator wrapper function.
+    """
+    @functools.wraps(fn)
+    @coroutine
+    def wrapper(*args, **kw):
+        _engine.activate()
+        try:
+            if iscoroutinefunction(fn):
+                yield from fn(*args, **kw)  # noqa
+            else:
+                fn(*args, **kw)
+        except Exception as err:
+            raise err
+        finally:
+            _engine.disable()
+
+    return wrapper

pook/api.py

@@ -1,14 +1,23 @@
-import re
 import functools
-from inspect import isfunction
+import re
 from contextlib import contextmanager
-from .engine import Engine
+from inspect import isfunction
 
+from .engine import Engine
+from .matcher import MatcherEngine
 from .mock import Mock
+from .mock_engine import MockEngine
 from .request import Request
 from .response import Response
-from .matcher import MatcherEngine
-from .mock_engine import MockEngine
+
+try:
+    from asyncio import iscoroutinefunction
+except ImportError:
+    iscoroutinefunction = None
+if iscoroutinefunction is not None:
+    from .activate_async import activate_async
+else:
+    activate_async = None
 
 # Public API symbols to export
 __all__ = (
@@ -96,6 +105,9 @@ def test_request():
         _engine.activate()
         return None
 
+    if iscoroutinefunction is not None and iscoroutinefunction(fn):
+        return activate_async(fn, _engine)
+
     @functools.wraps(fn)
     def wrapper(*args, **kw):
         _engine.activate()