TAP Producers

tappy integrates with unittest based test cases to produce TAP output. The producers come in three varieties: support with only the standard library, support for nose, and support for pytest.

  • TAPTestRunner - This subclass of unittest.TextTestRunner provides all the functionality of TextTestRunner and generates TAP files or streams.
  • tappy for nose - tappy provides a plugin (simply called TAP) for the nose testing tool.
  • tappy for pytest - tappy provides a plugin called tap for the pytest testing tool.

By default, the producers will create one TAP file for each TestCase executed by the test suite. The files will use the name of the test case class with a .tap extension. For example:

class TestFoo(unittest.TestCase):

    def test_identity(self):
        """Test numeric equality as an example."""
        self.assertTrue(1 == 1)

The class will create a file named TestFoo.tap containing the following.

# TAP results for TestFoo
ok 1 - Test numeric equality as an example.
1..1

The producers also have streaming modes which bypass the default runner output and write TAP to the output stream instead of files. This is useful for piping output directly to tools that read TAP natively.

$ nosetests --with-tap --tap-stream tap.tests.test_parser
# TAP results for TestParser
ok 1 - test_after_hash_is_not_description (tap.tests.test_parser.TestParser)
ok 2 - The parser extracts a bail out line.
ok 3 - The parser extracts a diagnostic line.
ok 4 - The TAP spec dictates that anything less than 13 is an error.
ok 5 - test_finds_description (tap.tests.test_parser.TestParser)
ok 6 - The parser extracts a not ok line.
ok 7 - The parser extracts a test number.
ok 8 - The parser extracts an ok line.
ok 9 - The parser extracts a plan line.
ok 10 - The parser extracts a plan line containing a SKIP.
1..10
_images/stream.gif

Examples

The TAPTestRunner works like the TextTestRunner. To use the runner, load test cases using the TestLoader and pass the tests to the run method. The sample below is the test runner used with tappy’s own tests.

import os
import unittest

from tap import TAPTestRunner

if __name__ == '__main__':
    tests_dir = os.path.dirname(os.path.abspath(__file__))
    loader = unittest.TestLoader()
    tests = loader.discover(tests_dir)
    runner = TAPTestRunner()
    runner.set_outdir('testout')
    runner.set_format('Hi: {method_name} - {short_description}')
    runner.run(tests)

Running tappy with nose is as straightforward as enabling the plugin when calling nosetests.

$ nosetests --with-tap
...............
----------------------------------------------------------------------
Ran 15 tests in 0.020s

OK

The pytest plugin is automatically activated for pytest when tappy is installed. Because it is automatically activated, pytest users should specify an output style.

$ py.test --tap-files
=========================== test session starts ============================
platform linux2 -- Python 2.7.6 -- py-1.4.30 -- pytest-2.7.2
rootdir: /home/matt/tappy, inifile:
plugins: tap.py
collected 94 items

tests/test_adapter.py .....
tests/test_directive.py ......
tests/test_line.py ......
tests/test_loader.py ......
tests/test_main.py .
tests/test_nose_plugin.py ......
tests/test_parser.py ................
tests/test_pytest_plugin.py .........
tests/test_result.py .......
tests/test_rules.py ........
tests/test_runner.py .......
tests/test_tracker.py .................

======================== 94 passed in 0.24 seconds =========================

The configuration options for each TAP tool are listed in the following sections.

TAPTestRunner

You can configure the TAPTestRunner from a set of class or instance methods.

  • set_stream - Enable streaming mode to send TAP output directly to the output stream. Use the set_stream instance method.

    runner = TAPTestRunner()
    runner.set_stream(True)
    
  • set_outdir - The TAPTestRunner gives the user the ability to set the output directory. Use the set_outdir class method.

    TAPTestRunner.set_outdir('/my/output/directory')
    
  • set_combined - TAP results can be directed into a single output file. Use the set_combined class method to store the results in testresults.tap.

    TAPTestRunner.set_combined(True)
    
  • set_format - Use the set_format class method to change the format of result lines. {method_name} and {short_description} are available options.

    TAPTestRunner.set_format('{method_name}: {short_description}')
    
  • set_header - Turn off or on the test case header output. The default is True (ie, the header is displayed.) Use the set_header instance method.

    runner = TAPTestRunner()
    runner.set_header(False)
    

nose TAP Plugin

Note

To use this plugin, install it with pip install nose-tap.

The nose TAP plugin is configured from command line flags.

  • --with-tap - This flag is required to enable the plugin.

  • --tap-stream - Enable streaming mode to send TAP output directly to the output stream.

  • --tap-combined - Store test results in a single output file in testresults.tap.

  • --tap-outdir - The nose TAP plugin also supports an optional output directory when you don’t want to store the .tap files wherever you executed nosetests.

    Use --tap-outdir followed by a directory path to store the files in a different place. The directory will be created if it does not exist.

  • --tap-format - Provide a different format for the result lines. {method_name} and {short_description} are available options. For example, '{method_name}: {short_description}'.

pytest TAP Plugin

Note

To use this plugin, install it with pip install pytest-tap.

The pytest TAP plugin is configured from command line flags. Since pytest automatically activates the TAP plugin, the plugin does nothing by default. Users must enable a TAP output mode (via --tap-stream|files|combined) or the plugin will take no action.

  • --tap-stream - Enable streaming mode to send TAP output directly to the output stream.

  • --tap-files - Store test results in individual test files. One test file is created for each test case.

  • --tap-combined - Store test results in a single output file in testresults.tap.

  • --tap-outdir - The pytest TAP plugin also supports an optional output directory when you don’t want to store the .tap files wherever you executed py.test.

    Use --tap-outdir followed by a directory path to store the files in a different place. The directory will be created if it does not exist.

Python and TAP

The TAP specification is open-ended on certain topics. This section clarifies how tappy interprets these topics.

The specification indicates that a test line represents a “test point” without explicitly defining “test point.” tappy assumes that each test line is per test method. TAP producers in other languages may output test lines per assertion, but the unit of work in the Python ecosystem is the test method (i.e. unittest, nose, and pytest all report per method by default).

tappy does not permit setting the plan. Instead, the plan is a count of the number of test methods executed. Python test runners execute all test methods in a suite, regardless of any errors encountered. Thus, the test method count should be an accurate measure for the plan.