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= Writing unit tests

This wiki page shows how to write your own unit tests for Trac or Trac plugin.

== Start writing `TestCase`s

Any unit test should derive from class `unittest.TestCase` in order to be called from `unittest.makeSuite`. Thus you can make a set of test cases, which are called test suite.

Usually you need to setup your `Environment` in order to have any access to your Trac environment. This can be done using `EnvironmentStub`.

This test suite can be executed as a normal python code.

Here's a simple Test case (from trac plugin [th:wiki/LogWatcherPlugin LogWatcherPlugin]) to explain the above:

{{{#!py
# -*- coding: utf-8 -*-

import os
import shutil
import tempfile
import unittest

from trac.test import EnvironmentStub

from logwatcher import api


class TestApi(unittest.TestCase):

    def setUp(self):
        self.env = EnvironmentStub(enable=[
            'trac.*', 'logwatcher.api'
        ])
        self.env.path = tempfile.mkdtemp()
        os.mkdir('%s/log' % self.env.path)

        self.env.config.set('logging', 'log_type', 'file')
        self.env.setup_log()

    def tearDown(self):
        self.env.reset_db()
        self.env.shutdown()
        shutil.rmtree(self.env.path)

    def test_get_logfile_name(self):
        test_api = api.LogViewerApi(self.env)
        logfile_name = test_api.get_logfile_name()
        self.assertIsNotNone(logfile_name, "log file name is None")


def suite():
    print "Starting **API** test suite"
    suite = unittest.TestSuite()
    suite.addTest(unittest.makeSuite(TestApi, 'test'))
    return suite

if __name__ == '__main__':
    unittest.main(defaultTest='suite')
}}}

== Using several test methods

You can use several test methods within a `TestCase` class; they need to start with `test`. When you use method `setUp` it will be executed for each test method. If you only want to "set up" your test environment once of your test case, you need to use class method `setUpClass`.

For example:
{{{#!py
# ... imports and such ...
class TestApi(unittest.TestCase):

    @classmethod
    def setUpClass(self, port=None):
        super(TestApi, self).setUpClass()
        self.env = EnvironmentStub(enable=[
            'trac.*', 'logwatcher.api'
        ])
        # ... more lines ...

    def test_get_logfile_name(self):
        # ... more lines ...

    def test_get_log_settings_default(self):
        # ... more lines ...

    @classmethod
    def tearDownClass(self):
        super(TestApi, self).tearDownClass()
        # you should also shutdown environment before deleting directory,
        # since it closes log files, shutdowns database connection and such
        self.env.shutdown()
        shutil.rmtree(dirPath)
}}}