Errors and Failures
===================

Let's look at tests that have errors and failures, first we need to make a
temporary copy of the entire testing directory (except .svn files which may
be read only):

    >>> import os.path, sys, tempfile, shutil
    >>> tmpdir = tempfile.mkdtemp()
    >>> directory_with_tests = os.path.join(tmpdir, 'testrunner-ex')
    >>> source = os.path.join(this_directory, 'testrunner-ex')
    >>> n = len(source) + 1
    >>> for root, dirs, files in os.walk(source):
    ...     dirs[:] = [d for d in dirs if d != ".svn"] # prune cruft
    ...     os.mkdir(os.path.join(directory_with_tests, root[n:]))
    ...     for f in files:
    ...         _ = shutil.copy(os.path.join(root, f),
    ...                         os.path.join(directory_with_tests, root[n:], f))

    >>> from zope import testrunner
    >>> defaults = [
    ...     '--path', directory_with_tests,
    ...     '--tests-pattern', '^sampletestsf?$',
    ...     ]

    >>> sys.argv = 'test --tests-pattern ^sampletests(f|_e|_f)?$ '.split()
    >>> testrunner.run_internal(defaults)
    ... # doctest: +NORMALIZE_WHITESPACE +ELLIPSIS
    Running samplelayers.Layer1 tests:
    ...
    Running zope.testrunner.layer.UnitTests tests:
    ...
    <BLANKLINE>
    <BLANKLINE>
    Failure in test eek (sample2.sampletests_e)
    Failed doctest test for sample2.sampletests_e.eek
      File "testrunner-ex/sample2/sampletests_e.py", line 28, in eek
    <BLANKLINE>
    ----------------------------------------------------------------------
    File "testrunner-ex/sample2/sampletests_e.py", line 30, in sample2.sampletests_e.eek
    Failed example:
        f()
    Exception raised:
        Traceback (most recent call last):
          File ".../doctest.py", line 1256, in __run
            compileflags, 1) in test.globs
          File "<doctest sample2.sampletests_e.eek[0]>", line 1, in ?
            f()
          File "testrunner-ex/sample2/sampletests_e.py", line 19, in f
            g()
          File "testrunner-ex/sample2/sampletests_e.py", line 24, in g
            x = y + 1
           - __traceback_info__: I don't know what Y should be.
        NameError: global name 'y' is not defined
    <BLANKLINE>
    <BLANKLINE>
    <BLANKLINE>
    Error in test test3 (sample2.sampletests_e.Test)
    Traceback (most recent call last):
      File "testrunner-ex/sample2/sampletests_e.py", line 43, in test3
        f()
      File "testrunner-ex/sample2/sampletests_e.py", line 19, in f
        g()
      File "testrunner-ex/sample2/sampletests_e.py", line 24, in g
        x = y + 1
       - __traceback_info__: I don't know what Y should be.
    NameError: global name 'y' is not defined
    <BLANKLINE>
    <BLANKLINE>
    <BLANKLINE>
    Failure in test testrunner-ex/sample2/e.txt
    Failed doctest test for e.txt
      File "testrunner-ex/sample2/e.txt", line 0
    <BLANKLINE>
    ----------------------------------------------------------------------
    File "testrunner-ex/sample2/e.txt", line 4, in e.txt
    Failed example:
        f()
    Exception raised:
        Traceback (most recent call last):
          File ".../doctest.py", line 1256, in __run
            compileflags, 1) in test.globs
          File "<doctest e.txt[1]>", line 1, in ?
            f()
          File "<doctest e.txt[0]>", line 2, in f
            return x
        NameError: global name 'x' is not defined
    <BLANKLINE>
    <BLANKLINE>
    <BLANKLINE>
    Failure in test test (sample2.sampletests_f.Test)
    Traceback (most recent call last):
      File "testrunner-ex/sample2/sampletests_f.py", line 21, in test
        self.assertEqual(1,0)
      File "/usr/local/python/2.3/lib/python2.3/unittest.py", line 302, in failUnlessEqual
        raise self.failureException, \
    AssertionError: 1 != 0
    <BLANKLINE>
      Ran 164 tests with 3 failures, 1 errors and 0 skipped in N.NNN seconds.
    Tearing down left over layers:
      Tear down zope.testrunner.layer.UnitTests in N.NNN seconds.
    Total: 329 tests, 3 failures, 1 errors and 0 skipped in N.NNN seconds.
    True

We see that we get an error report and a traceback for the failing
test.  In addition, the test runner returned True, indicating that
there was an error.

If we ask for verbosity, the dotted output will be interrupted, and
there'll be a summary of the errors at the end of the test:

    >>> sys.argv = 'test --tests-pattern ^sampletests(f|_e|_f)?$ -uv'.split()
    >>> testrunner.run_internal(defaults)
    ... # doctest: +NORMALIZE_WHITESPACE +REPORT_NDIFF
    Running tests at level 1
    Running zope.testrunner.layer.UnitTests tests:
    ...
      Running:
    .................................................................................................
    <BLANKLINE>
    Failure in test eek (sample2.sampletests_e)
    Failed doctest test for sample2.sampletests_e.eek
      File "testrunner-ex/sample2/sampletests_e.py", line 28, in eek
    <BLANKLINE>
    ----------------------------------------------------------------------
    File "testrunner-ex/sample2/sampletests_e.py", line 30,
        in sample2.sampletests_e.eek
    Failed example:
        f()
    Exception raised:
        Traceback (most recent call last):
          File ".../doctest.py", line 1256, in __run
            compileflags, 1) in test.globs
          File "<doctest sample2.sampletests_e.eek[0]>", line 1, in ?
            f()
          File "testrunner-ex/sample2/sampletests_e.py", line 19, in f
            g()
          File "testrunner-ex/sample2/sampletests_e.py", line 24, in g
            x = y + 1
           - __traceback_info__: I don't know what Y should be.
        NameError: global name 'y' is not defined
    <BLANKLINE>
    ...
    <BLANKLINE>
    <BLANKLINE>
    Error in test test3 (sample2.sampletests_e.Test)
    Traceback (most recent call last):
      File "testrunner-ex/sample2/sampletests_e.py", line 43, in test3
        f()
      File "testrunner-ex/sample2/sampletests_e.py", line 19, in f
        g()
      File "testrunner-ex/sample2/sampletests_e.py", line 24, in g
        x = y + 1
       - __traceback_info__: I don't know what Y should be.
    NameError: global name 'y' is not defined
    <BLANKLINE>
    ...
    <BLANKLINE>
    Failure in test testrunner-ex/sample2/e.txt
    Failed doctest test for e.txt
      File "testrunner-ex/sample2/e.txt", line 0
    <BLANKLINE>
    ----------------------------------------------------------------------
    File "testrunner-ex/sample2/e.txt", line 4, in e.txt
    Failed example:
        f()
    Exception raised:
        Traceback (most recent call last):
          File ".../doctest.py", line 1256, in __run
            compileflags, 1) in test.globs
          File "<doctest e.txt[1]>", line 1, in ?
            f()
          File "<doctest e.txt[0]>", line 2, in f
            return x
        NameError: global name 'x' is not defined
    <BLANKLINE>
    .
    <BLANKLINE>
    Failure in test test (sample2.sampletests_f.Test)
    Traceback (most recent call last):
      File "testrunner-ex/sample2/sampletests_f.py", line 21, in test
        self.assertEqual(1,0)
      File ".../unittest.py", line 302, in failUnlessEqual
        raise self.failureException, \
    AssertionError: 1 != 0
    <BLANKLINE>
    ................................................................................................
    <BLANKLINE>
      Ran 164 tests with 3 failures, 1 errors and 0 skipped in 0.040 seconds.
    ...
    <BLANKLINE>
    Tests with errors:
       test3 (sample2.sampletests_e.Test)
    <BLANKLINE>
    Tests with failures:
       eek (sample2.sampletests_e)
       testrunner-ex/sample2/e.txt
       test (sample2.sampletests_f.Test)
    True

Similarly for progress output, the progress ticker will be interrupted:

    >>> sys.argv = ('test --tests-pattern ^sampletests(f|_e|_f)?$ -u -ssample2'
    ...             ' -p').split()
    >>> testrunner.run_internal(defaults)
    ... # doctest: +NORMALIZE_WHITESPACE +REPORT_NDIFF
    Running zope.testrunner.layer.UnitTests tests:
      Set up zope.testrunner.layer.UnitTests in N.NNN seconds.
      Running:
        1/47 (2.1%)
    <BLANKLINE>
    Failure in test eek (sample2.sampletests_e)
    Failed doctest test for sample2.sampletests_e.eek
      File "testrunner-ex/sample2/sampletests_e.py", line 28, in eek
    <BLANKLINE>
    ----------------------------------------------------------------------
    File "testrunner-ex/sample2/sampletests_e.py", line 30, in sample2.sampletests_e.eek
    Failed example:
        f()
    Exception raised:
        Traceback (most recent call last):
          File ".../doctest.py", line 1256, in __run
            compileflags, 1) in test.globs
          File "<doctest sample2.sampletests_e.eek[0]>", line 1, in ?
            f()
          File "testrunner-ex/sample2/sampletests_e.py", line 19, in f
            g()
          File "testrunner-ex/sample2/sampletests_e.py", line 24, in g
            x = y + 1
           - __traceback_info__: I don't know what Y should be.
        NameError: global name 'y' is not defined
    <BLANKLINE>
        2/47 (4.3%)\r
                   \r
        3/47 (6.4%)\r
                   \r
        4/47 (8.5%)
    <BLANKLINE>
    Error in test test3 (sample2.sampletests_e.Test)
    Traceback (most recent call last):
      File "testrunner-ex/sample2/sampletests_e.py", line 43, in test3
        f()
      File "testrunner-ex/sample2/sampletests_e.py", line 19, in f
        g()
      File "testrunner-ex/sample2/sampletests_e.py", line 24, in g
        x = y + 1
       - __traceback_info__: I don't know what Y should be.
    NameError: global name 'y' is not defined
    <BLANKLINE>
        5/47 (10.6%)\r
                   \r
        6/47 (12.8%)\r
                    \r
        7/47 (14.9%)
    <BLANKLINE>
    Failure in test testrunner-ex/sample2/e.txt
    Failed doctest test for e.txt
      File "testrunner-ex/sample2/e.txt", line 0
    <BLANKLINE>
    ----------------------------------------------------------------------
    File "testrunner-ex/sample2/e.txt", line 4, in e.txt
    Failed example:
        f()
    Exception raised:
        Traceback (most recent call last):
          File ".../doctest.py", line 1256, in __run
            compileflags, 1) in test.globs
          File "<doctest e.txt[1]>", line 1, in ?
            f()
          File "<doctest e.txt[0]>", line 2, in f
            return x
        NameError: global name 'x' is not defined
    <BLANKLINE>
        8/47 (17.0%)
    <BLANKLINE>
    Failure in test test (sample2.sampletests_f.Test)
    Traceback (most recent call last):
      File "testrunner-ex/sample2/sampletests_f.py", line 21, in test
        self.assertEqual(1,0)
      File ".../unittest.py", line 302, in failUnlessEqual
        raise self.failureException, \
    AssertionError: 1 != 0
    <BLANKLINE>
        9/47 (19.1%)\r
                    \r
        10/47 (21.3%)\r
                     \r
        11/47 (23.4%)\r
                     \r
        12/47 (25.5%)\r
                     \r
        13/47 (27.7%)\r
                     \r
        14/47 (29.8%)\r
                     \r
        15/47 (31.9%)\r
                     \r
        16/47 (34.0%)\r
                     \r
        17/47 (36.2%)\r
                     \r
        18/47 (38.3%)\r
                     \r
        19/47 (40.4%)\r
                     \r
        20/47 (42.6%)\r
                     \r
        21/47 (44.7%)\r
                     \r
        22/47 (46.8%)\r
                     \r
        23/47 (48.9%)\r
                     \r
        24/47 (51.1%)\r
                     \r
        25/47 (53.2%)\r
                     \r
        26/47 (55.3%)\r
                     \r
        27/47 (57.4%)\r
                     \r
        28/47 (59.6%)\r
                     \r
        29/47 (61.7%)\r
                     \r
        30/47 (63.8%)\r
                     \r
        31/47 (66.0%)\r
                     \r
        32/47 (68.1%)\r
                     \r
        33/47 (70.2%)\r
                     \r
        34/47 (72.3%)\r
                     \r
        35/47 (74.5%)\r
                     \r
        36/47 (76.6%)\r
                     \r
        37/47 (78.7%)\r
                     \r
        38/47 (80.9%)\r
                     \r
        39/47 (83.0%)\r
                     \r
        40/47 (85.1%)\r
                     \r
        41/47 (87.2%)\r
                     \r
        42/47 (89.4%)\r
                     \r
        43/47 (91.5%)\r
                     \r
        44/47 (93.6%)\r
                     \r
        45/47 (95.7%)\r
                     \r
        46/47 (97.9%)\r
                     \r
        47/47 (100.0%)\r
                      \r
    <BLANKLINE>
      Ran 47 tests with 3 failures, 1 errors and 0 skipped in 0.054 seconds.
    Tearing down left over layers:
      Tear down zope.testrunner.layer.UnitTests in N.NNN seconds.
    True

If you also want a summary of errors at the end, ask for verbosity as well
as progress output.


Suppressing multiple doctest errors
-----------------------------------

Often, when a doctest example fails, the failure will cause later
examples in the same test to fail.  Each failure is reported:

    >>> sys.argv = 'test --tests-pattern ^sampletests_1$'.split()
    >>> testrunner.run_internal(defaults) # doctest: +NORMALIZE_WHITESPACE
    Running zope.testrunner.layer.UnitTests tests:
      Set up zope.testrunner.layer.UnitTests in N.NNN seconds.
    <BLANKLINE>
    <BLANKLINE>
    Failure in test eek (sample2.sampletests_1)
    Failed doctest test for sample2.sampletests_1.eek
      File "testrunner-ex/sample2/sampletests_1.py", line 17, in eek
    <BLANKLINE>
    ----------------------------------------------------------------------
    File "testrunner-ex/sample2/sampletests_1.py", line 19,
         in sample2.sampletests_1.eek
    Failed example:
        x = y
    Exception raised:
        Traceback (most recent call last):
          File ".../doctest.py", line 1256, in __run
            compileflags, 1) in test.globs
          File "<doctest sample2.sampletests_1.eek[0]>", line 1, in ?
            x = y
        NameError: name 'y' is not defined
    ----------------------------------------------------------------------
    File "testrunner-ex/sample2/sampletests_1.py", line 21,
         in sample2.sampletests_1.eek
    Failed example:
        x
    Exception raised:
        Traceback (most recent call last):
          File ".../doctest.py", line 1256, in __run
            compileflags, 1) in test.globs
          File "<doctest sample2.sampletests_1.eek[1]>", line 1, in ?
            x
        NameError: name 'x' is not defined
    ----------------------------------------------------------------------
    File "testrunner-ex/sample2/sampletests_1.py", line 24,
         in sample2.sampletests_1.eek
    Failed example:
        z = x + 1
    Exception raised:
        Traceback (most recent call last):
          File ".../doctest.py", line 1256, in __run
            compileflags, 1) in test.globs
          File "<doctest sample2.sampletests_1.eek[2]>", line 1, in ?
            z = x + 1
        NameError: name 'x' is not defined
    <BLANKLINE>
      Ran 1 tests with 1 failures, 0 errors and 0 skipped in 0.002 seconds.
    Tearing down left over layers:
      Tear down zope.testrunner.layer.UnitTests in N.NNN seconds.
    True

This can be a bit confusing, especially when there are enough tests
that they scroll off a screen.  Often you just want to see the first
failure.  This can be accomplished with the -1 option (for "just show
me the first failed example in a doctest" :)

    >>> sys.argv = 'test --tests-pattern ^sampletests_1$ -1'.split()
    >>> testrunner.run_internal(defaults) # doctest:
    Running zope.testrunner.layer.UnitTests tests:
      Set up zope.testrunner.layer.UnitTests in N.NNN seconds.
    <BLANKLINE>
    <BLANKLINE>
    Failure in test eek (sample2.sampletests_1)
    Failed doctest test for sample2.sampletests_1.eek
      File "testrunner-ex/sample2/sampletests_1.py", line 17, in eek
    <BLANKLINE>
    ----------------------------------------------------------------------
    File "testrunner-ex/sample2/sampletests_1.py", line 19,
         in sample2.sampletests_1.eek
    Failed example:
        x = y
    Exception raised:
        Traceback (most recent call last):
          File ".../doctest.py", line 1256, in __run
            compileflags, 1) in test.globs
          File "<doctest sample2.sampletests_1.eek[0]>", line 1, in ?
            x = y
        NameError: name 'y' is not defined
    <BLANKLINE>
      Ran 1 tests with 1 failures, 0 errors and 0 skipped in 0.001 seconds.
    Tearing down left over layers:
      Tear down zope.testrunner.layer.UnitTests in N.NNN seconds.
    True

The --hide-secondary-failures option is an alias for -1:

    >>> sys.argv = (
    ...     'test --tests-pattern ^sampletests_1$'
    ...     ' --hide-secondary-failures'
    ...     ).split()
    >>> testrunner.run_internal(defaults) # doctest:
    Running zope.testrunner.layer.UnitTests tests:
      Set up zope.testrunner.layer.UnitTests in N.NNN seconds.
    <BLANKLINE>
    <BLANKLINE>
    Failure in test eek (sample2.sampletests_1)
    Failed doctest test for sample2.sampletests_1.eek
      File "testrunner-ex/sample2/sampletests_1.py", line 17, in eek
    <BLANKLINE>
    ----------------------------------------------------------------------
    File "testrunner-ex/sample2/sampletests_1.py", line 19, in sample2.sampletests_1.eek
    Failed example:
        x = y
    Exception raised:
        Traceback (most recent call last):
          File ".../doctest.py", line 1256, in __run
            compileflags, 1) in test.globs
          File "<doctest sample2.sampletests_1.eek[0]>", line 1, in ?
            x = y
        NameError: name 'y' is not defined
    <BLANKLINE>
      Ran 1 tests with 1 failures, 0 errors and 0 skipped in 0.001 seconds.
    Tearing down left over layers:
      Tear down zope.testrunner.layer.UnitTests in N.NNN seconds.
    True

The --show-secondary-failures option counters -1 (or it's alias),
causing the second and subsequent errors to be shown.  This is useful
if -1 is provided by a test script by inserting it ahead of
command-line options in sys.argv.

    >>> sys.argv = (
    ...     'test --tests-pattern ^sampletests_1$'
    ...     ' --hide-secondary-failures --show-secondary-failures'
    ...     ).split()
    >>> testrunner.run_internal(defaults) # doctest: +NORMALIZE_WHITESPACE
    Running zope.testrunner.layer.UnitTests tests:
      Set up zope.testrunner.layer.UnitTests in N.NNN seconds.
    <BLANKLINE>
    <BLANKLINE>
    Failure in test eek (sample2.sampletests_1)
    Failed doctest test for sample2.sampletests_1.eek
      File "testrunner-ex/sample2/sampletests_1.py", line 17, in eek
    <BLANKLINE>
    ----------------------------------------------------------------------
    File "testrunner-ex/sample2/sampletests_1.py", line 19, in sample2.sampletests_1.eek
    Failed example:
        x = y
    Exception raised:
        Traceback (most recent call last):
          File ".../doctest.py", line 1256, in __run
            compileflags, 1) in test.globs
          File "<doctest sample2.sampletests_1.eek[0]>", line 1, in ?
            x = y
        NameError: name 'y' is not defined
    ----------------------------------------------------------------------
    File "testrunner-ex/sample2/sampletests_1.py", line 21, in sample2.sampletests_1.eek
    Failed example:
        x
    Exception raised:
        Traceback (most recent call last):
          File ".../doctest.py", line 1256, in __run
            compileflags, 1) in test.globs
          File "<doctest sample2.sampletests_1.eek[1]>", line 1, in ?
            x
        NameError: name 'x' is not defined
    ----------------------------------------------------------------------
    File "testrunner-ex/sample2/sampletests_1.py", line 24, in sample2.sampletests_1.eek
    Failed example:
        z = x + 1
    Exception raised:
        Traceback (most recent call last):
          File ".../doctest.py", line 1256, in __run
            compileflags, 1) in test.globs
          File "<doctest sample2.sampletests_1.eek[2]>", line 1, in ?
            z = x + 1
        NameError: name 'x' is not defined
    <BLANKLINE>
      Ran 1 tests with 1 failures, 0 errors and 0 skipped in 0.002 seconds.
    Tearing down left over layers:
      Tear down zope.testrunner.layer.UnitTests in N.NNN seconds.
    True


Getting diff output for doctest failures
----------------------------------------

If a doctest has large expected and actual output, it can be hard to
see differences when expected and actual output differ.  The --ndiff,
--udiff, and --cdiff options can be used to get diff output of various
kinds.

    >>> sys.argv = 'test --tests-pattern ^pledge$'.split()
    >>> _ = testrunner.run_internal(defaults)
    Running zope.testrunner.layer.UnitTests tests:
      Set up zope.testrunner.layer.UnitTests in N.NNN seconds.
    <BLANKLINE>
    <BLANKLINE>
    Failure in test pledge (pledge)
    Failed doctest test for pledge.pledge
      File "testrunner-ex/pledge.py", line 24, in pledge
    <BLANKLINE>
    ----------------------------------------------------------------------
    File "testrunner-ex/pledge.py", line 26, in pledge.pledge
    Failed example:
        print_pledge()
    Expected:
        I give my pledge, as an earthling,
        to save, and faithfully, to defend from waste,
        the natural resources of my planet.
        It's soils, minerals, forests, waters, and wildlife.
        <BLANKLINE>
    Got:
        I give my pledge, as and earthling,
        to save, and faithfully, to defend from waste,
        the natural resources of my planet.
        It's soils, minerals, forests, waters, and wildlife.
        <BLANKLINE>
    <BLANKLINE>
      Ran 1 tests with 1 failures, 0 errors and 0 skipped in 0.002 seconds.
    Tearing down left over layers:
      Tear down zope.testrunner.layer.UnitTests in N.NNN seconds.

Here, the actual output uses the word "and" rather than the word "an",
but it's a bit hard to pick this out.  We can use the various diff
outputs to see this better. We could modify the test to ask for diff
output, but it's easier to use one of the diff options.

The --ndiff option requests a diff using Python's ndiff utility. This
is the only method that marks differences within lines as well as
across lines. For example, if a line of expected output contains digit
1 where actual output contains letter l, a line is inserted with a
caret marking the mismatching column positions.

    >>> sys.argv = 'test --tests-pattern ^pledge$ --ndiff'.split()
    >>> _ = testrunner.run_internal(defaults)
    Running zope.testrunner.layer.UnitTests tests:
      Set up zope.testrunner.layer.UnitTests in N.NNN seconds.
    <BLANKLINE>
    <BLANKLINE>
    Failure in test pledge (pledge)
    Failed doctest test for pledge.pledge
      File "testrunner-ex/pledge.py", line 24, in pledge
    <BLANKLINE>
    ----------------------------------------------------------------------
    File "testrunner-ex/pledge.py", line 26, in pledge.pledge
    Failed example:
        print_pledge()
    Differences (ndiff with -expected +actual):
        - I give my pledge, as an earthling,
        + I give my pledge, as and earthling,
        ?                        +
          to save, and faithfully, to defend from waste,
          the natural resources of my planet.
          It's soils, minerals, forests, waters, and wildlife.
        <BLANKLINE>
    <BLANKLINE>
      Ran 1 tests with 1 failures, 0 errors and 0 skipped in 0.003 seconds.
    Tearing down left over layers:
      Tear down zope.testrunner.layer.UnitTests in N.NNN seconds.

The -udiff option requests a standard "unified" diff:

    >>> sys.argv = 'test --tests-pattern ^pledge$ --udiff'.split()
    >>> _ = testrunner.run_internal(defaults)
    Running zope.testrunner.layer.UnitTests tests:
      Set up zope.testrunner.layer.UnitTests in N.NNN seconds.
    <BLANKLINE>
    <BLANKLINE>
    Failure in test pledge (pledge)
    Failed doctest test for pledge.pledge
      File "testrunner-ex/pledge.py", line 24, in pledge
    <BLANKLINE>
    ----------------------------------------------------------------------
    File "testrunner-ex/pledge.py", line 26, in pledge.pledge
    Failed example:
        print_pledge()
    Differences (unified diff with -expected +actual):
        @@ -1,3 +1,3 @@
        -I give my pledge, as an earthling,
        +I give my pledge, as and earthling,
         to save, and faithfully, to defend from waste,
         the natural resources of my planet.
    <BLANKLINE>
      Ran 1 tests with 1 failures, 0 errors and 0 skipped in 0.002 seconds.
    Tearing down left over layers:
      Tear down zope.testrunner.layer.UnitTests in N.NNN seconds.

The -cdiff option requests a standard "context" diff:

    >>> sys.argv = 'test --tests-pattern ^pledge$ --cdiff'.split()
    >>> _ = testrunner.run_internal(defaults)
    Running zope.testrunner.layer.UnitTests tests:
      Set up zope.testrunner.layer.UnitTests in N.NNN seconds.
    <BLANKLINE>
    <BLANKLINE>
    Failure in test pledge (pledge)
    Failed doctest test for pledge.pledge
      File "testrunner-ex/pledge.py", line 24, in pledge
    <BLANKLINE>
    ----------------------------------------------------------------------
    File "testrunner-ex/pledge.py", line 26, in pledge.pledge
    Failed example:
        print_pledge()
    Differences (context diff with expected followed by actual):
        ***************
        *** 1,3 ****
        ! I give my pledge, as an earthling,
          to save, and faithfully, to defend from waste,
          the natural resources of my planet.
        --- 1,3 ----
        ! I give my pledge, as and earthling,
          to save, and faithfully, to defend from waste,
          the natural resources of my planet.
    <BLANKLINE>
      Ran 1 tests with 1 failures, 0 errors and 0 skipped in 0.002 seconds.
    Tearing down left over layers:
      Tear down zope.testrunner.layer.UnitTests in N.NNN seconds.

Specifying more than one diff option at once causes an error:

    >>> sys.argv = 'test --tests-pattern ^pledge$ --cdiff --udiff'.split()
    >>> _ = testrunner.run_internal(defaults)
    Traceback (most recent call last):
    ...
    SystemExit: 1

    >>> sys.argv = 'test --tests-pattern ^pledge$ --cdiff --ndiff'.split()
    >>> _ = testrunner.run_internal(defaults)
    Traceback (most recent call last):
    ...
    SystemExit: 1

    >>> sys.argv = 'test --tests-pattern ^pledge$ --udiff --ndiff'.split()
    >>> _ = testrunner.run_internal(defaults)
    Traceback (most recent call last):
    ...
    SystemExit: 1


Testing-Module Import Errors
----------------------------

If there are errors when importing a test module, these errors are
reported.  In order to illustrate a module with a syntax error, we create
one now:  this module used to be checked in to the project, but then it was
included in distributions of projects using zope.testrunner too, and distutils
complained about the syntax error when it compiled Python files during
installation of such projects.  So first we create a module with bad syntax:

    >>> badsyntax_path = os.path.join(directory_with_tests,
    ...                               "sample2", "sampletests_i.py")
    >>> f = open(badsyntax_path, "w")
    >>> print("importx unittest", file=f)  # syntax error
    >>> f.close()

Then run the tests:

    >>> sys.argv = ('test --tests-pattern ^sampletests(f|_i)?$ --layer 1 '
    ...            ).split()
    >>> testrunner.run_internal(defaults)
    ... # doctest: +NORMALIZE_WHITESPACE
    Test-module import failures:
    <BLANKLINE>
    Module: sample2.sampletests_i
    <BLANKLINE>
    Traceback (most recent call last):
      File "testrunner-ex/sample2/sampletests_i.py", line 1
        importx unittest
                       ^
    SyntaxError: invalid syntax
    <BLANKLINE>
    <BLANKLINE>
    Module: sample2.sample21.sampletests_i
    <BLANKLINE>
    Traceback (most recent call last):
      File "testrunner-ex/sample2/sample21/sampletests_i.py", line 15, in ?
        import zope.testrunner.huh
    ImportError: No module named huh
    <BLANKLINE>
    <BLANKLINE>
    Module: sample2.sample23.sampletests_i
    <BLANKLINE>
    Traceback (most recent call last):
      File "testrunner-ex/sample2/sample23/sampletests_i.py", line 18, in ?
        class Test(unittest.TestCase):
      File "testrunner-ex/sample2/sample23/sampletests_i.py", line 23, in Test
        raise TypeError('eek')
    TypeError: eek
    <BLANKLINE>
    <BLANKLINE>
    Running samplelayers.Layer1 tests:
      Set up samplelayers.Layer1 in 0.000 seconds.
      Ran 9 tests with 0 failures, 3 errors and 0 skipped in 0.000 seconds.
    Running samplelayers.Layer11 tests:
      Set up samplelayers.Layer11 in 0.000 seconds.
      Ran 26 tests with 0 failures, 3 errors and 0 skipped in 0.007 seconds.
    Running samplelayers.Layer111 tests:
      Set up samplelayers.Layerx in 0.000 seconds.
      Set up samplelayers.Layer111 in 0.000 seconds.
      Ran 26 tests with 0 failures, 3 errors and 0 skipped in 0.007 seconds.
    Running samplelayers.Layer112 tests:
      Tear down samplelayers.Layer111 in 0.000 seconds.
      Set up samplelayers.Layer112 in 0.000 seconds.
      Ran 26 tests with 0 failures, 3 errors and 0 skipped in 0.007 seconds.
    Running samplelayers.Layer12 tests:
      Tear down samplelayers.Layer112 in 0.000 seconds.
      Tear down samplelayers.Layerx in 0.000 seconds.
      Tear down samplelayers.Layer11 in 0.000 seconds.
      Set up samplelayers.Layer12 in 0.000 seconds.
      Ran 26 tests with 0 failures, 3 errors and 0 skipped in 0.007 seconds.
    Running samplelayers.Layer121 tests:
      Set up samplelayers.Layer121 in 0.000 seconds.
      Ran 26 tests with 0 failures, 3 errors and 0 skipped in 0.007 seconds.
    Running samplelayers.Layer122 tests:
      Tear down samplelayers.Layer121 in 0.000 seconds.
      Set up samplelayers.Layer122 in 0.000 seconds.
      Ran 26 tests with 0 failures, 3 errors and 0 skipped in 0.006 seconds.
    Tearing down left over layers:
      Tear down samplelayers.Layer122 in 0.000 seconds.
      Tear down samplelayers.Layer12 in 0.000 seconds.
      Tear down samplelayers.Layer1 in 0.000 seconds.
    <BLANKLINE>
    Test-modules with import problems:
      sample2.sampletests_i
      sample2.sample21.sampletests_i
      sample2.sample23.sampletests_i
    Total: 165 tests, 0 failures, 3 errors and 0 skipped in N.NNN seconds.
    True


Reporting Errors to Calling Processes
-------------------------------------

The testrunner returns the error status, indicating that the tests
failed.  This can be useful for an invoking process that wants to
monitor the result of a test run.

This is applied when invoking the testrunner using the ``run()`` function
instead of ``run_internal()``:

    >>> sys.argv = (
    ...     'test --tests-pattern ^sampletests_1$'.split())
    >>> try:
    ...     testrunner.run(defaults)
    ... except SystemExit as e:
    ...     print('exited with code', e.code)
    ... else:
    ...     print('sys.exit was not called')
    ... # doctest: +ELLIPSIS
    Running zope.testrunner.layer.UnitTests tests:
      Set up zope.testrunner.layer.UnitTests in N.NNN seconds.
    ...
      Ran 1 tests with 1 failures, 0 errors and 0 skipped in 0.002 seconds.
    Tearing down left over layers:
      Tear down zope.testrunner.layer.UnitTests in N.NNN seconds.
    exited with code 1

Passing tests exit with code 0 according to UNIX practices:

    >>> sys.argv = (
    ...     'test --tests-pattern ^sampletests$'.split())
    >>> try:
    ...     testrunner.run(defaults)
    ... except SystemExit as e2:
    ...     print('exited with code', e2.code)
    ... else:
    ...     print('sys.exit was not called')
    ... # doctest: +ELLIPSIS
    Running samplelayers.Layer11 tests:
    ...
    Running zope.testrunner.layer.UnitTests tests:
      Tear down samplelayers.Layer122 in N.NNN seconds.
      Tear down samplelayers.Layer12 in N.NNN seconds.
      Tear down samplelayers.Layer1 in N.NNN seconds.
      Set up zope.testrunner.layer.UnitTests in N.NNN seconds.
      Ran 130 tests with 0 failures, 0 errors and 0 skipped in N.NNN seconds.
    Tearing down left over layers:
      Tear down zope.testrunner.layer.UnitTests in N.NNN seconds.
    Total: 286 tests, 0 failures, 0 errors and 0 skipped in N.NNN seconds.
    exited with code 0

And remove the temporary directory:

    >>> shutil.rmtree(tmpdir)

