README FOR IDLE TESTS IN IDLELIB.IDLE_TEST 0. Quick Start Automated unit tests were added in 3.3 for Python 3.x. To run the tests from a command line: python -m test.test_idle Human-mediated tests were added later in 3.4. python -m idlelib.idle_test.htest 1. Test Files The idle directory, idlelib, has over 60 xyz.py files. The idle_test subdirectory contains test_xyz.py for each implementation file xyz.py. To add a test for abc.py, open idle_test/template.py and immediately Save As test_abc.py. Insert 'abc' on the first line, and replace 'zzdummy' with 'abc. Remove the imports of requires and tkinter if not needed. Otherwise, add to the tkinter imports as needed. Add a prefix to 'Test' for the initial test class. The template class contains code needed or possibly needed for gui tests. See the next section if doing gui tests. If not, and not needed for further classes, this code can be removed. Add the following at the end of abc.py. If an htest was added first, insert the import and main lines before the htest lines. if __name__ == "__main__": from unittest import main main('idlelib.idle_test.test_abc', verbosity=2, exit=False) The ', exit=False' is only needed if an htest follows. 2. GUI Tests When run as part of the Python test suite, Idle GUI tests need to run test.support.requires('gui'). A test is a GUI test if it creates a tkinter.Tk root or master object either directly or indirectly by instantiating a tkinter or idle class. GUI tests cannot run in test processes that either have no graphical environment available or are not allowed to use it. To guard a module consisting entirely of GUI tests, start with from test.support import requires requires('gui') To guard a test class, put "requires('gui')" in its setUpClass function. The template.py file does this. To avoid interfering with other GUI tests, all GUI objects must be destroyed and deleted by the end of the test. The Tk root created in a setUpX function should be destroyed in the corresponding tearDownX and the module or class attribute deleted. Others widgets should descend from the single root and the attributes deleted BEFORE root is destroyed. See https://bugs.python.org/issue20567. @classmethod def setUpClass(cls): requires('gui') cls.root = tk.Tk() cls.text = tk.Text(root) @classmethod def tearDownClass(cls): del cls.text cls.root.update_idletasks() cls.root.destroy() del cls.root The update_idletasks call is sometimes needed to prevent the following warning either when running a test alone or as part of the test suite (#27196). It should not hurt if not needed. can't invoke "event" command: application has been destroyed ... "ttk::ThemeChanged" If a test creates instance 'e' of EditorWindow, call 'e._close()' before or as the first part of teardown. The effect of omitting this depends on the later shutdown. Then enable the after_cancel loop in the template. This prevents messages like the following. bgerror failed to handle background error. Original error: invalid command name "106096696timer_event" Error in bgerror: can't invoke "tk" command: application has been destroyed Requires('gui') causes the test(s) it guards to be skipped if any of these conditions are met: - The tests are being run by regrtest.py, and it was started without enabling the "gui" resource with the "-u" command line option. - The tests are being run on Windows by a service that is not allowed to interact with the graphical environment. - The tests are being run on Linux and X Windows is not available. - The tests are being run on Mac OSX in a process that cannot make a window manager connection. - tkinter.Tk cannot be successfully instantiated for some reason. - test.support.use_resources has been set by something other than regrtest.py and does not contain "gui". Tests of non-GUI operations should avoid creating tk widgets. Incidental uses of tk variables and messageboxes can be replaced by the mock classes in idle_test/mock_tk.py. The mock text handles some uses of the tk Text widget. 3. Running Unit Tests Assume that xyz.py and test_xyz.py both end with a unittest.main() call. Running either from an Idle editor runs all tests in the test_xyz file with the version of Python running Idle. Test output appears in the Shell window. The 'verbosity=2' option lists all test methods in the file, which is appropriate when developing tests. The 'exit=False' option is needed in xyx.py files when an htest follows. The following command lines also run all test methods, including GUI tests, in test_xyz.py. (Both '-m idlelib' and '-m idlelib.idle' start Idle and so cannot run tests.) python -m idlelib.xyz python -m idlelib.idle_test.test_xyz The following runs all idle_test/test_*.py tests interactively. >>> import unittest >>> unittest.main('idlelib.idle_test', verbosity=2) The following run all Idle tests at a command line. Option '-v' is the same as 'verbosity=2'. python -m unittest -v idlelib.idle_test python -m test -v -ugui test_idle python -m test.test_idle The idle tests are 'discovered' by idlelib.idle_test.__init__.load_tests, which is also imported into test.test_idle. Normally, neither file should be changed when working on individual test modules. The third command runs unittest indirectly through regrtest. The same happens when the entire test suite is run with 'python -m test'. So that command must work for buildbots to stay green. Idle tests must not disturb the environment in a way that makes other tests fail (issue 18081). To run an individual Testcase or test method, extend the dotted name given to unittest on the command line or use the test -m option. The latter allows use of other regrtest options. When using the latter, all components of the pattern must be present, but any can be replaced by '*'. python -m unittest -v idlelib.idle_test.test_xyz.Test_case.test_meth python -m test -m idlelib.idle_test.text_xyz.Test_case.test_meth test_idle The test suite can be run in an IDLE user process from Shell. >>> import test.autotest # Issue 25588, 2017/10/13, 3.6.4, 3.7.0a2. There are currently failures not usually present, and this does not work when run from the editor. 4. Human-mediated Tests Human-mediated tests are widget tests that cannot be automated but need human verification. They are contained in idlelib/idle_test/htest.py, which has instructions. (Some modules need an auxiliary function, identified with "# htest # on the header line.) The set is about complete, though some tests need improvement. To run all htests, run the htest file from an editor or from the command line with: python -m idlelib.idle_test.htest 5. Test Coverage Install the coverage package into your Python 3.6 site-packages directory. (Its exact location depends on the OS). > python3 -m pip install coverage (On Windows, replace 'python3 with 'py -3.6' or perhaps just 'python'.) The problem with running coverage with repository python is that coverage uses absolute imports for its submodules, hence it needs to be in a directory in sys.path. One solution: copy the package to the directory containing the cpython repository. Call it 'dev'. Then run coverage either directly or from a script in that directory so that 'dev' is prepended to sys.path. Either edit or add dev/.coveragerc so it looks something like this. --- # .coveragerc sets coverage options. [run] branch = True [report] # Regexes for lines to exclude from consideration exclude_lines = # Don't complain if non-runnable code isn't run: if 0: if __name__ == .__main__.: .*# htest # if not _utest: if _htest: --- The additions for IDLE are 'branch = True', to test coverage both ways, and the last three exclude lines, to exclude things peculiar to IDLE that are not executed during tests. A script like the following cover.bat (for Windows) is very handy. --- @echo off rem Usage: cover filename [test_ suffix] # proper case required by coverage rem filename without .py, 2nd parameter if test is not test_filename setlocal set py=f:\dev\3x\pcbuild\win32\python_d.exe set src=idlelib.%1 if "%2" EQU "" set tst=f:/dev/3x/Lib/idlelib/idle_test/test_%1.py if "%2" NEQ "" set tst=f:/dev/ex/Lib/idlelib/idle_test/test_%2.py %py% -m coverage run --pylib --source=%src% %tst% %py% -m coverage report --show-missing %py% -m coverage html start htmlcov\3x_Lib_idlelib_%1_py.html rem Above opens new report; htmlcov\index.html displays report index --- The second parameter was added for tests of module x not named test_x. (There were several before modules were renamed, now only one is left.)