Merge pull request #2055 from freakboy3742/test-handlers

Test coverage for handlers

changes/2055.misc.rst

@@ -0,0 +1 @@
+Full test coverage for handlers was added.

core/src/toga/__init__.py

@@ -107,11 +107,7 @@ def _package_version(file, name):
         # If it *is* in the environment, but the code isn't a git checkout (e.g.,
         # it's been pip installed non-editable) the call to get_version() will fail.
         # If either of these occurs, read version from the installer metadata.
-        try:
-            from importlib import metadata as importlib_metadata
-        except ImportError:
-            # Backwards compatibility - importlib.metadata was added in Python 3.8
-            import importlib_metadata
+        from importlib import metadata as importlib_metadata
 
         # The Toga package names as defined in setup.cfg all use dashes.
         package = "toga-core" if name == "toga" else name.replace("_", "-")

core/src/toga/app.py

@@ -7,6 +7,7 @@
 from builtins import id as identifier
 from collections.abc import MutableSet
 from email.message import Message
+from importlib import metadata as importlib_metadata
 from typing import Any, Iterable, Protocol
 
 from toga.command import CommandSet
@@ -17,12 +18,6 @@
 from toga.widgets.base import Widget, WidgetRegistry
 from toga.window import Window
 
-try:
-    from importlib import metadata as importlib_metadata
-except ImportError:
-    # Backwards compatibility - importlib.metadata was added in Python 3.8
-    import importlib_metadata
-
 # Make sure deprecation warnings are shown by default
 warnings.filterwarnings("default", category=DeprecationWarning)
 

core/src/toga/handlers.py

@@ -10,28 +10,41 @@ def __init__(self, handler):
         self.native = handler
 
 
-async def long_running_task(generator, cleanup):
+async def long_running_task(interface, generator, cleanup):
     """Run a generator as an asynchronous coroutine."""
     try:
-        while True:
-            delay = next(generator)
-            await asyncio.sleep(delay)
-    except StopIteration:
-        if cleanup:
-            cleanup()
+        try:
+            while True:
+                delay = next(generator)
+                if delay:
+                    await asyncio.sleep(delay)
+        except StopIteration as e:
+            result = e.value
     except Exception as e:
         print("Error in long running handler:", e, file=sys.stderr)
         traceback.print_exc()
+    else:
+        if cleanup:
+            try:
+                cleanup(interface, result)
+            except Exception as e:
+                print("Error in long running handler cleanup:", e, file=sys.stderr)
+                traceback.print_exc()
 
 
 async def handler_with_cleanup(handler, cleanup, interface, *args, **kwargs):
     try:
         result = await handler(interface, *args, **kwargs)
-        if cleanup:
-            cleanup(interface, result)
     except Exception as e:
         print("Error in async handler:", e, file=sys.stderr)
         traceback.print_exc()
+    else:
+        if cleanup:
+            try:
+                cleanup(interface, result)
+            except Exception as e:
+                print("Error in async handler cleanup:", e, file=sys.stderr)
+                traceback.print_exc()
 
 
 def wrapped_handler(interface, handler, cleanup=None):
@@ -62,17 +75,24 @@ def _handler(widget, *args, **kwargs):
                     handler_with_cleanup(handler, cleanup, interface, *args, **kwargs)
                 )
             else:
-                result = handler(interface, *args, **kwargs)
-                if inspect.isgenerator(result):
-                    asyncio.ensure_future(long_running_task(result, cleanup))
+                try:
+                    result = handler(interface, *args, **kwargs)
+                except Exception as e:
+                    print("Error in handler:", e, file=sys.stderr)
+                    traceback.print_exc()
                 else:
-                    try:
-                        if cleanup:
-                            cleanup(interface, result)
-                        return result
-                    except Exception as e:
-                        print("Error in handler:", e, file=sys.stderr)
-                        traceback.print_exc()
+                    if inspect.isgenerator(result):
+                        asyncio.ensure_future(
+                            long_running_task(interface, result, cleanup)
+                        )
+                    else:
+                        try:
+                            if cleanup:
+                                cleanup(interface, result)
+                            return result
+                        except Exception as e:
+                            print("Error in handler cleanup:", e, file=sys.stderr)
+                            traceback.print_exc()
 
         _handler._raw = handler