Automated User Interface Testing for Set-Top Boxes & Smart TVs
|Copyright:||Copyright (C) 2013-2014 Stb-tester.com Ltd, 2012-2014 YouView TV Ltd. and other contributors|
|License:||LGPL v2.1 or (at your option) any later version (see LICENSE file in the source distribution for details)|
stbt record [options]
stbt run [options] script[::testcase]
stbt record will record a test case by listening for remote-control keypresses, taking screenshots from the set-top box as it goes.
You then (manually) crop the screenshots to the region of interest.
(Optionally) you manually edit the generated test script, which will look something like this:
def test_that_i_can_tune_to_bbc_one_from_the_guide(): press("MENU") wait_for_match("Guide.png") press("OK") wait_for_match("BBC One.png")
stbt run will play back the given test script, returning an exit status of success or failure for easy integration with your existing test reporting system.
stbt has other auxiliary sub-commands; run stbt --help for details.
A remote control to use for controlling the set top box. uri can be:
A GStreamer pipeline providing a video stream to use as video output from the set-top box under test. For the Hauppauge HD PVR use:
v4l2src device=/dev/video0 ! tsdemux ! h264parse
|A GStreamer pipeline to use for video output, like xvimagesink.|
|Restart the GStreamer source pipeline when video loss is detected, to work around the behaviour of the Hauppauge HD PVR video-capture device.|
Enable debug output.
With stbt run, specify -v twice to dump intermediate images from the image processing algorithm to the ./stbt-debug directory. Note that this will dump a lot of files -- several images per frame processed. This is intended for debugging the image processing algorithm; it isn't intended for end users.
Additional options to stbt run
|Record a video (in the HTML5-compatible WebM format) to the specified file.|
Additional options to stbt record
The source of remote control presses. uri can be:
|-o <filename>, --output-filename=<filename>|
|The file to write the generated test script to.|
All parameters that can be passed to the stbt tools can also be specified in configuration files. Configuration is searched for in the following files (with later files taking precedence):
$STBT_CONFIG_FILE is a colon-separated list of files where the item specified at the beginning takes precedence.
These files are simple ini files with the form:
[global] source_pipeline = videotestsrc sink_pipeline = xvimagesink sync=false control = None verbose = 0 [run] save_video = video.webm [record] output_file = test.py control_recorder = file:///dev/stdin
Each key corresponds to a command line option with hyphens replaced with underscores.
0 on success; 1 on test script failure; 2 on any other error.
Test scripts indicate failure (the system under test didn't behave as expected) by raising an instance of stbt.UITestFailure (or a subclass thereof) or AssertionError (which is raised by Python's assert statement). Any other exception is considered a test error (a logic error in the test script, an error in the system under test's environment, or an error in the test framework itself).
The test rig consists of a Linux server, with:
- A video-capture card (for capturing the output from the system under test)
- An infrared receiver (for recording the system-under-test's infrared protocol)
- An infrared emitter (for controlling the system under test)
Video capture card
You'll need a capture card with drivers supporting the V4L2 API (Video-for-Linux 2). We recommend a capture card with mature open-source drivers, preferably drivers already present in recent versions of the Linux kernel.
The Hauppauge HD PVR works well (and works out of the box on recent versions of Fedora), though it doesn't support 1080p. If you need an HDCP stripper, try the HD Fury III.
Infra-red emitter and receiver
An IR emitter+receiver such as the RedRat3, plus a LIRC configuration file with the key codes for your set-top box's remote control.
Using software components instead
If you don't mind instrumenting the system under test, you don't even need the above hardware components.
stb-tester uses GStreamer, an open source multimedia framework. Instead of a video-capture card you can use any GStreamer video-source element. For example:
- If you run tests against a VM running the set-top box software instead of a physical set-top box, you could use the ximagesrc GStreamer element to capture video from the VM's X Window.
- If your set-top box uses DirectFB, you could install the DirectFBSource GStreamer element (https://bugzilla.gnome.org/show_bug.cgi?id=685877) on the set-top box to stream video to a updsrc GStreamer element on the test rig.
Instead of a hardware infra-red receiver + emitter, you can use a software equivalent (for example a server running on the set-top box that listens on a TCP socket instead of listening for infra-red signals, and your own application for emulating remote-control keypresses). Using a software remote control avoids all issues of IR interference in rigs testing multiple set-top boxes at once.
An 8-core machine will be able to drive 4 set-top boxes simultaneously with at least 1 frame per second per set-top box.
- A Unixy operating system (we have only tested on Linux and Mac OS X).
- Drivers for any required hardware components.
- GStreamer 1.0 (multimedia framework) + gstreamer-plugins-base + gstreamer-plugins-good.
- python 2.7 + pygst + docutils (for building the documentation) + nose (for the self-tests).
- OpenCV (image processing library) version >= 2.0.0, and the OpenCV python bindings.
- For the Hauppauge video capture device you'll need the gstreamer-libav package (e.g. from the rpmfusion-free repository) for H.264 decoding.
INSTALLING FROM SOURCE
Run "make install" from the stb-tester source directory.
See https://github.com/stb-tester/stb-tester/wiki/Getting-started-with-stb-tester for the required dependencies and configuration.
TEST SCRIPT FORMAT
The test scripts produced and run by stbt record and stbt run, respectively, are actually python scripts, so you can use the full power of python. Don't get too carried away, though; aim for simplicity, readability, and maintainability.
See the Python API documentation at http://stb-tester.com/stb-tester-one/rev2015.1/python-api
TEST SCRIPT BEST PRACTICES
- When cropping images to be matched by a test case, you must select a region that will not be present when the test case fails, and that does not contain any elements that might be absent when the test case succeeds. For example, you must not include any part of a live TV stream (which will be different each time the test case is run), nor translucent menu overlays with live TV showing through.
- Crop template images as tightly as possible. For example if you're looking for a button, don't include the background outside of the button. (This is particularly important if your system-under-test is still under development and minor aesthetic changes to the UI are common.)
- Always follow a press with a wait_for_match -- don't assume that the press worked.
- Use press_until_match instead of assuming that the position of a menu item will never change within that menu.
- Use the timeout_secs parameter of wait_for_match and wait_for_motion instead of using time.sleep.
- Rename the template images captured by stbt record to a name that explains the contents of the image.
- Extract common navigation patterns into separate python functions. It is useful to start each test script by calling a function that brings the system-under-test to a known state.