Debugging and testing¶
Running widgets as scripts¶
To run a widget without canvas - for debugging and for nitpicking about the GUI
- the widget module must be executable as a script. This is handled by
WidgetPreview. It is typically
used as follows
if __name__ == "__main__": WidgetPreview(OWMyWidgetName).run()
OWMyWidgetName is the widget’s class.
We can also pass the data to the widget. For instance,
if __name__ == "__main__": WidgetPreview(OWMyWidgetName).run(Orange.data.Table("iris"))
passes the Iris data set to the widget. Passing data in this way requires that there is a single or default signal for the argument’s data type. Multiple signals can be passed as keyword arguments in which the names correspond to signal handlers:
if __name__ == "__main__": data = Orange.data.Table("iris") WidgetPreview(OWScatterPlot).run( set_data=data, set_subset_data=data[:30] )
If the signal handler accepts multiple inputs, they can be passed as a list, like in the following method in the Table widget.
if __name__ == "__main__": WidgetPreview(OWDataTable).run( [(Table("iris"), "iris"), (Table("brown-selected"), "brown-selected"), (Table("housing"), "housing") ] )
Preview ends by tearing down the widget and calling
sys.exit with the
widget’s exit code. This can be prevented by adding a no_exit=True argument.
We can also prevent showing the widget and starting the event loop by using
no_exec=True. This, together with some previewers method described below,
can be used for debugging the widget. For example, OWRank’s preview,
if __name__ == "__main__": from Orange.classification import RandomForestLearner WidgetPreview(OWRank).run( set_learner=(RandomForestLearner(), (3, 'Learner', None)), set_data=Table("heart_disease.tab"))
can be temporarily modified to
if __name__ == "__main__": from Orange.classification import RandomForestLearner previewer = WidgetPreview(OWRank) previewer.run(Table("heart_disease.tab"), no_exit=True) previewer.send_signals( set_learner=(RandomForestLearner(), (3, 'Learner', None))) previewer.run()
which shows the widget twice, allows us a finer control of signal passing, and offers adding some breakpoints.
- class orangewidget.utils.widgetpreview.WidgetPreview(widget_cls)¶
A helper class for widget previews.
- run(input_data=None, *, no_exec=False, no_exit=False, **kwargs)¶
Run a preview of the widget;
It first creates a widget, unless it exists from the previous call. This can only happen if no_exit was set to True.
Next, it passes the data signals to the widget. Data given as positional argument must be of a type for which there exist a single or a default handler. Signals can also be given by keyword arguments, where the name of the argument is the name of the handler method. If the data is a list of tuples, the sequence of tuples is sent to the same handler.
Next, the method shows the widget and starts the event loop, unless no_exec argument is set to True.
Finally, unless the argument no_exit is set to True, the method tears down the widget, deletes the reference to the widget and calls Python’s garbage collector, as an effort to catch any crashes due to widget members (typically
QGraphicsSceneelements) outliving the widget. It then calls
sys.exitwith the exit code from the application’s main loop.
If no_exit is set to True, the run keeps the widget alive. In this case, subsequent calls to run or other methods (send_signals, exec_widget) will use the same widget.
QApplicationand construct the widget.
- send_signals(input_data=None, **kwargs)¶
Send signals to the widget
Show the widget and start the
QApplication’s main loop.
Save settings and delete the widget.
Orange provides a base class
WidgetTest with helper methods for unit
- class orangewidget.tests.base.WidgetTest(methodName='runTest')¶
Base class for widget tests
Contains helper methods widget creation and working with signals.
All widgets should be created by the create_widget method, as this will ensure they are created correctly.
- classmethod setUpClass()¶
Prepare environment for test execution
Construct a dummy signal manager and monkey patch OWReport.get_instance to return a manually created instance.
Process any pending events before the next test is executed.
- create_widget(cls: Type[orangewidget.tests.base.T], stored_settings: Optional[dict] = None, reset_default_settings: bool = True) orangewidget.tests.base.T ¶
Create a widget instance using mock signal_manager.
When used with default parameters, it also overrides settings stored on disk with default defined in class.
After widget is created, QApplication.process_events is called to allow any singleShot timers defined in __init__ to execute.
- Return type
- static reset_default_settings(widget)¶
Reset default setting values for widget
Discards settings read from disk and changes stored by fast_save
widget (OWBaseWidget) – widget to reset settings for
- process_events(until: Optional[callable] = None, timeout=5000)¶
Process Qt events, optionally until until returns something True-ish.
Needs to be called manually as QApplication.exec is never called.
- Return type
If until is not None, the True-ish result of its call.
Show widget in interactive mode.
Useful for debugging tests, as widget can be inspected manually.
- send_signal(input, value=<object object>, *args, widget=None, wait=-1)¶
Send signal to widget by calling appropriate triggers.
- send_signals(signals, *args, widget=None, wait=- 1)¶
Send signals to widget by calling appropriate triggers. After all the signals are send, widget’s handleNewSignals() in invoked.
- wait_until_stop_blocking(widget=None, wait=5000)¶
Wait until the widget stops blocking i.e. finishes computation.
- wait_until_finished(widget: Optional[orangewidget.widget.OWBaseWidget] = None, timeout=5000) None ¶
Wait until the widget finishes computation.
The widget is considered finished once all its outputs are valid.
- commit_and_wait(widget=None, wait=5000)¶
Unconditional commit and wait until finished.
- get_output(output=None, widget=None, wait=5000)¶
Return the last output that has been sent from the widget.
- Return type
The last sent value of given output or None if nothing has been sent.
Context that simulates pressed modifiers
Since QTest.keypress requries pressing some key, we simulate pressing “BassBoost” that looks exotic enough to not meddle with anything.
Test whether widget error, warning and info messages are derived from its (direct) parent message classes.