1# Copyright (c) 2009, Google Inc. All rights reserved.
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15# this software without specific prior written permission.
16#
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27# OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
28#
29# Class for unittest support.  Used for capturing stderr/stdout.
30
31import logging
32import sys
33from StringIO import StringIO
34
35import webkitpy.thirdparty.unittest2 as unittest
36
37
38class OutputCapture(object):
39    # By default we capture the output to a stream. Other modules may override
40    # this function in order to do things like pass through the output. See
41    # webkitpy.test.main for an example.
42    @staticmethod
43    def stream_wrapper(stream):
44        return StringIO()
45
46    def __init__(self):
47        self.saved_outputs = dict()
48        self._log_level = logging.INFO
49
50    def set_log_level(self, log_level):
51        self._log_level = log_level
52        if hasattr(self, '_logs_handler'):
53            self._logs_handler.setLevel(self._log_level)
54
55    def _capture_output_with_name(self, output_name):
56        stream = getattr(sys, output_name)
57        captured_output = self.stream_wrapper(stream)
58        self.saved_outputs[output_name] = stream
59        setattr(sys, output_name, captured_output)
60        return captured_output
61
62    def _restore_output_with_name(self, output_name):
63        captured_output = getattr(sys, output_name).getvalue()
64        setattr(sys, output_name, self.saved_outputs[output_name])
65        del self.saved_outputs[output_name]
66        return captured_output
67
68    def capture_output(self):
69        self._logs = StringIO()
70        self._logs_handler = logging.StreamHandler(self._logs)
71        self._logs_handler.setLevel(self._log_level)
72        self._logger = logging.getLogger()
73        self._orig_log_level = self._logger.level
74        self._logger.addHandler(self._logs_handler)
75        self._logger.setLevel(min(self._log_level, self._orig_log_level))
76        return (self._capture_output_with_name("stdout"), self._capture_output_with_name("stderr"))
77
78    def restore_output(self):
79        self._logger.removeHandler(self._logs_handler)
80        self._logger.setLevel(self._orig_log_level)
81        self._logs_handler.flush()
82        self._logs.flush()
83        logs_string = self._logs.getvalue()
84        delattr(self, '_logs_handler')
85        delattr(self, '_logs')
86        return (self._restore_output_with_name("stdout"), self._restore_output_with_name("stderr"), logs_string)
87
88    def assert_outputs(self, testcase, function, args=[], kwargs={}, expected_stdout="", expected_stderr="", expected_exception=None, expected_logs=None):
89        self.capture_output()
90        try:
91            if expected_exception:
92                return_value = testcase.assertRaises(expected_exception, function, *args, **kwargs)
93            else:
94                return_value = function(*args, **kwargs)
95        finally:
96            (stdout_string, stderr_string, logs_string) = self.restore_output()
97
98        if hasattr(testcase, 'assertMultiLineEqual'):
99            testassert = testcase.assertMultiLineEqual
100        else:
101            testassert = testcase.assertEqual
102
103        testassert(stdout_string, expected_stdout)
104        testassert(stderr_string, expected_stderr)
105        if expected_logs is not None:
106            testassert(logs_string, expected_logs)
107        # This is a little strange, but I don't know where else to return this information.
108        return return_value
109
110
111class OutputCaptureTestCaseBase(unittest.TestCase):
112    maxDiff = None
113
114    def setUp(self):
115        unittest.TestCase.setUp(self)
116        self.output_capture = OutputCapture()
117        (self.__captured_stdout, self.__captured_stderr) = self.output_capture.capture_output()
118
119    def tearDown(self):
120        del self.__captured_stdout
121        del self.__captured_stderr
122        self.output_capture.restore_output()
123        unittest.TestCase.tearDown(self)
124
125    def assertStdout(self, expected_stdout):
126        self.assertEqual(expected_stdout, self.__captured_stdout.getvalue())
127
128    def assertStderr(self, expected_stderr):
129        self.assertEqual(expected_stderr, self.__captured_stderr.getvalue())
130