28 Test
The framework provides several new primitive functions that simulate
user actions, which may be used to test applications. You use these
primitives and combine them just as regular Racket functions. For
example,
sends a keystroke event to the window with the keyboard focus and invokes
the callback function for the “Save” menu item from the “File” menu.
This has the same effect as if the user typed the key “A”, pulled
down the “File” menu and selected “Save”.
It is possible to load this portion of the framework without loading
the rest of the framework. Use
(require framework/test).
Currently, the test engine has primitives for pushing
buttons, setting check-boxes and choices, sending keystrokes,
selecting menu items and clicking the mouse. Many functions
that are also useful in application testing, such as
traversing a tree of panels, getting the text from a canvas,
determining if a window is shown, and so on, exist in GRacket.
28.1 Actions and completeness
The actions associated with a testing primitive may not have finished
when the primitive returns to its caller.
Some actions may yield control before they can complete.
For example, selecting “Save As...” from the “File” menu
opens a dialog box and will not complete until the “OK”
or “Cancel” button is pushed.
However, all testing functions wait at least a minimum interval
before returning to give the action a chance to finish.
This interval controls the speed at which the test suite runs,
and gives some slack time for events to complete.
The default interval is 100 milliseconds. The interval can be queried
or set with test:run-interval.
A primitive action will not return until the run-interval has
expired and the action has finished, raised an error, or yielded.
The number of incomplete actions is given by
test:number-pending-actions.
Note:
Once a primitive action is started, it is not possible to undo it
or kill its remaining effect.
Thus, it is not possible to write a utility that flushes the
incomplete actions and resets number-pending-actions to zero.
However, actions which do not complete right away often provide a
way to cancel themselves.
For example, many dialog boxes have a “Cancel” button which will
terminate the action with no further effect.
But this is accomplished by sending an additional action
(the button push), not by undoing the original action.
28.2 Errors
Errors in the primitive actions (which necessarily run in the
handler thread) are caught and reraised in the calling thread.
However, the primitive actions can only guarantee that the action
has started, and they may return before the action has completed.
As a consequence, an action may raise an error long after the
function that started it has returned.
In this case, the error is saved and reraised at the first opportunity
(the next primitive action).
The test engine keeps a buffer for one error, saving only the
first error. Any subsequent errors are discarded.
Reraising an error empties the buffer, allowing the next error
to be saved.
The function test:reraise-error
reraises any pending errors.
28.3 Technical Issues
28.3.1 Active Frame
The Self Test primitive actions all implicitly apply to the
top-most (active) frame.
28.3.2 Thread Issues
The code started by the primitive actions must run in the handler
thread of the eventspace where the event takes place. As a result,
the test suite that invokes the primitive actions must not run
in that handler thread (or else some actions will deadlock). See
make-eventspace
for more info.
28.3.3 Window Manager (Unix only)
In order for the Self Tester to work correctly, the window manager
must set the keyboard focus to follow the active frame.
This is the default behavior in Microsoft Windows and MacOS,
but not in X windows.
In X windows, you must explicitly tell your window manager to set the
keyboard focus to the top-most frame, regardless of the position of the
actual mouse.
28.4 Test Functions
Simulates pushing button. If a string is supplied, the
primitive searches for a button labelled with that string in the
active frame. Otherwise, it pushes the button argument.
Sets the radio-box to state. If state is a
string, this function finds the choice with that label and
if it is a number, it uses the number as an index into the
state. If the number is out of range or if the label isn’t
in the radio box, an exception is raised.
If
radio-box is a string, this function searches for a
radio-box% object with a label matching that string,
otherwise it uses
radio-box itself.
Finds a
radio-box% that has a label
entry
and sets the radio-box to
entry.
Clears the
check-box% item if
state is
#f, and sets it
otherwise.
If
check-box is a string,
this function searches for a
check-box% with a label matching that string,
otherwise it uses
check-box itself.
Selects
choice’s item
str. If
choice is a string,
this function searches for a
choice% with a label matching
that string, otherwise it uses
choice itself.
Selects
list-box’s item
str. If
list-box is a string,
this function searches for a
list-box% with a label matching
that string, otherwise it uses
list-box itself.
This function simulates a user pressing a key. The argument,
key,
is just like the argument to the
get-key-code
method of the
key-event% class.
Note:
To send the “Enter” key, use #\return,
not #\newline.
The 'shift or 'noshift modifier is implicitly set from key,
but is overridden by the argument list. The 'shift modifier is
set for any capitol alpha-numeric letters and any of the following characters:
| #\? #\: #\~ #\\ #\| |
| #\< #\> #\{ #\} #\[ #\] #\( #\) |
| #\! #\@ #\# #\$ #\% #\^ #\& #\* #\_ #\+ |
If conflicting modifiers are provided, the ones later in the list are used.
Selects the menu-item named item in the menu named menu.
Note:
The string for the menu item does not include its keyboard equivalent.
For example, to select “New” from the “File” menu,
use “New”, not “New Ctrl+m n”.
Simulates a mouse click at the coordinate (x,y) in the currently
focused
window, assuming that it supports the
on-event method.
Use
test:button-push to click on a button.
On the Macintosh, 'right corresponds to holding down the command
modifier key while clicking and 'middle cannot be generated.
Under Windows, 'middle can only be generated if the user has a
three button mouse.
The modifiers later in the list modifiers take precedence over
ones that appear earlier.
See also
Actions and completeness.
The first case in the case-lambda sets
the run interval to
msec milliseconds and the second
returns the current setting.
This parameter that specifies which evenspaces
(see also
Event Dispatching and Eventspaces)
are considered when finding the frontmost frame.
The first case
sets the parameter to
func. The procedure
func will be
invoked with no arguments to determine the eventspaces to consider
when finding the frontmost frame for simulated user events.
The second case
returns the current value of the parameter. This will be a procedure
which, when invoked, returns a list of eventspaces.
Moves the keyboard focus to a new window within the currently active
frame. Unfortunately, neither this function nor any other function in
the test engine can cause the focus to move from the top-most (active) frame.
Use this function to simulate clicking on the close box of a frame.
Closes tlw with this expression:
Calls test for each child of the top-level-focus-frame
and returns #t if test ever does, otherwise
returns #f. If there
is no top-level-focus-window, returns #f.
Returns the number of pending events (those that haven’t completed yet)
Runs the function f as if it was a simulated event.