Tree @debian/1.8.0-1 (Download .tar.gz)
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 250 251 252 253 254 255 256 257 258 259 260 261 262 263 264 265 266 267 268 269 270 271 272 273 274 275 276 | PyHamcrest ========== .. image:: https://pypip.in/v/PyHamcrest/badge.png :alt: Release Status :target: https://crate.io/packages/PyHamcrest .. image:: https://pypip.in/d/PyHamcrest/badge.png :alt: Downloads :target: https://crate.io/packages/PyHamcrest .. image:: https://travis-ci.org/hamcrest/PyHamcrest.png?branch=master :alt: Build Status :target: https://travis-ci.org/hamcrest/PyHamcrest Introduction ============ PyHamcrest is a framework for writing matcher objects, allowing you to declaratively define "match" rules. There are a number of situations where matchers are invaluable, such as UI validation, or data filtering, but it is in the area of writing flexible tests that matchers are most commonly used. This tutorial shows you how to use PyHamcrest for unit testing. When writing tests it is sometimes difficult to get the balance right between overspecifying the test (and making it brittle to changes), and not specifying enough (making the test less valuable since it continues to pass even when the thing being tested is broken). Having a tool that allows you to pick out precisely the aspect under test and describe the values it should have, to a controlled level of precision, helps greatly in writing tests that are "just right." Such tests fail when the behavior of the aspect under test deviates from the expected behavior, yet continue to pass when minor, unrelated changes to the behaviour are made. Installation ============ Hamcrest can be installed using the usual Python packaging tools. It depends on distribute, but as long as you have a network connection when you install, the installation process will take care of that for you. My first PyHamcrest test ======================== We'll start by writing a very simple PyUnit test, but instead of using PyUnit's ``assertEqual`` method, we'll use PyHamcrest's ``assert_that`` construct and the standard set of matchers: .. code:: python from hamcrest import * import unittest class BiscuitTest(unittest.TestCase): def testEquals(self): theBiscuit = Biscuit('Ginger') myBiscuit = Biscuit('Ginger') assert_that(theBiscuit, equal_to(myBiscuit)) if __name__ == '__main__': unittest.main() The ``assert_that`` function is a stylized sentence for making a test assertion. In this example, the subject of the assertion is the object ``theBiscuit``, which is the first method parameter. The second method parameter is a matcher for ``Biscuit`` objects, here a matcher that checks one object is equal to another using the Python ``==`` operator. The test passes since the ``Biscuit`` class defines an ``__eq__`` method. If you have more than one assertion in your test you can include an identifier for the tested value in the assertion: .. code:: python assert_that(theBiscuit.getChocolateChipCount(), equal_to(10), 'chocolate chips') assert_that(theBiscuit.getHazelnutCount(), equal_to(3), 'hazelnuts') As a convenience, assert_that can also be used to verify a boolean condition: .. code:: python assert_that(theBiscuit.isCooked(), 'cooked') This is equivalent to the ``assert_`` method of unittest.TestCase, but because it's a standalone function, it offers greater flexibility in test writing. Predefined matchers =================== PyHamcrest comes with a library of useful matchers: * Object * ``equal_to`` - match equal object * ``has_length`` - match ``len()`` * ``has_property`` - match value of property with given name * ``has_properties`` - match an object that has all of the given properties. * ``has_string`` - match ``str()`` * ``instance_of`` - match object type * ``none``, ``not_none`` - match ``None``, or not ``None`` * ``same_instance`` - match same object * Number * ``close_to`` - match number close to a given value * ``greater_than``, ``greater_than_or_equal_to``, ``less_than``, ``less_than_or_equal_to`` - match numeric ordering * Text * ``contains_string`` - match part of a string * ``ends_with`` - match the end of a string * ``equal_to_ignoring_case`` - match the complete string but ignore case * ``equal_to_ignoring_whitespace`` - match the complete string but ignore extra whitespace * ``matches_regexp`` - match a regular expression in a string * ``starts_with`` - match the beginning of a string * ``string_contains_in_order`` - match parts of a string, in relative order * Logical * ``all_of`` - ``and`` together all matchers * ``any_of`` - ``or`` together all matchers * ``anything`` - match anything, useful in composite matchers when you don't care about a particular value * ``is_not`` - negate the matcher * Sequence * ``contains`` - exactly match the entire sequence * ``contains_inanyorder`` - match the entire sequence, but in any order * ``has_item`` - match if given item appears in the sequence * ``has_items`` - match if all given items appear in the sequence, in any order * ``is_in`` - match if item appears in the given sequence * ``only_contains`` - match if sequence's items appear in given list * Dictionary * ``has_entries`` - match dictionary with list of key-value pairs * ``has_entry`` - match dictionary containing a key-value pair * ``has_key`` - match dictionary with a key * ``has_value`` - match dictionary with a value * Decorator * ``calling`` - wrap a callable in a deffered object, for subsequent matching on calling behaviour * ``raises`` - Ensure that a deferred callable raises as expected * ``described_as`` - give the matcher a custom failure description * ``is_`` - decorator to improve readability - see `Syntactic sugar` below The arguments for many of these matchers accept not just a matching value, but another matcher, so matchers can be composed for greater flexibility. For example, ``only_contains(less_than(5))`` will match any sequence where every item is less than 5. Syntactic sugar =============== PyHamcrest strives to make your tests as readable as possible. For example, the ``is_`` matcher is a wrapper that doesn't add any extra behavior to the underlying matcher. The following assertions are all equivalent: .. code:: python assert_that(theBiscuit, equal_to(myBiscuit)) assert_that(theBiscuit, is_(equal_to(myBiscuit))) assert_that(theBiscuit, is_(myBiscuit)) The last form is allowed since ``is_(value)`` wraps most non-matcher arguments with ``equal_to``. But if the argument is a type, it is wrapped with ``instance_of``, so the following are also equivalent: .. code:: python assert_that(theBiscuit, instance_of(Biscuit)) assert_that(theBiscuit, is_(instance_of(Biscuit))) assert_that(theBiscuit, is_(Biscuit)) *Note that PyHamcrest's ``is_`` matcher is unrelated to Python's ``is`` operator. The matcher for object identity is ``same_instance``.* Writing custom matchers ======================= PyHamcrest comes bundled with lots of useful matchers, but you'll probably find that you need to create your own from time to time to fit your testing needs. This commonly occurs when you find a fragment of code that tests the same set of properties over and over again (and in different tests), and you want to bundle the fragment into a single assertion. By writing your own matcher you'll eliminate code duplication and make your tests more readable! Let's write our own matcher for testing if a calendar date falls on a Saturday. This is the test we want to write: .. code:: python def testDateIsOnASaturday(self): d = datetime.date(2008, 04, 26) assert_that(d, is_(on_a_saturday())) And here's the implementation: .. code:: python from hamcrest.core.base_matcher import BaseMatcher from hamcrest.core.helpers.hasmethod import hasmethod class IsGivenDayOfWeek(BaseMatcher): def __init__(self, day): self.day = day # Monday is 0, Sunday is 6 def _matches(self, item): if not hasmethod(item, 'weekday'): return False return item.weekday() == self.day def describe_to(self, description): day_as_string = ['Monday', 'Tuesday', 'Wednesday', 'Thursday', 'Friday', 'Saturday', 'Sunday'] description.append_text('calendar date falling on ') \ .append_text(day_as_string[self.day]) def on_a_saturday(): return IsGivenDayOfWeek(5) For our Matcher implementation we implement the ``_matches`` method - which calls the ``weekday`` method after confirming that the argument (which may not be a date) has such a method - and the ``describe_to`` method - which is used to produce a failure message when a test fails. Here's an example of how the failure message looks: .. code:: python assert_that(datetime.date(2008, 04, 06), is_(on_a_saturday())) fails with the message:: AssertionError: Expected: is calendar date falling on Saturday got: <2008-04-06> Let's say this matcher is saved in a module named ``isgivendayofweek``. We could use it in our test by importing the factory function ``on_a_saturday``: .. code:: python from hamcrest import * import unittest from isgivendayofweek import on_a_saturday class DateTest(unittest.TestCase): def testDateIsOnASaturday(self): d = datetime.date(2008, 04, 26) assert_that(d, is_(on_a_saturday())) if __name__ == '__main__': unittest.main() Even though the ``on_a_saturday`` function creates a new matcher each time it is called, you should not assume this is the only usage pattern for your matcher. Therefore you should make sure your matcher is stateless, so a single instance can be reused between matches. More resources ============== * Documentation_ * Package_ * Sources_ * Hamcrest_ .. _Documentation: http://readthedocs.org/docs/pyhamcrest/en/V1.7.1/ .. _Package: http://pypi.python.org/pypi/PyHamcrest .. _Sources: https://github.com/hamcrest/PyHamcrest .. _Hamcrest: http://hamcrest.org |
Commit History @debian/1.8.0-1
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- new release David Villa Alises 11 years ago
- Imported Debian patch 1.6-3 David Villa Alises 11 years ago
- quilt patch to remove upstream egg David Villa Alises 11 years ago
- removing upstream egg David Villa Alises 11 years ago
- new standard versions David Villa Alises 11 years ago
- new minor release David Villa Alises 12 years ago
- drop patches and use debian/examles instead Piotr Ożarowski 12 years ago
- remove quilt from control and rules (source format = 3.0 (quilt)) Piotr Ożarowski 12 years ago
- new dependency: quilt David Villa Alises 12 years ago
- patch to add examples David Villa Alises 12 years ago
- rename with the orig name David Villa Alises 12 years ago
- Imported Debian patch 1.6-1 David Villa Alises 12 years ago
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