Welcome to MatchMaker’s documentation!¶
matchmaker makes it easy to write hamcrest matchers with minimum coding.
It includes decorators that turn simple functions into hamcrest matchers. The only requirement for these functions is that they must return boolean values, and they can optionally include a docstring that will be used as a descriptive text when matching fails.
The sources can be found in GitHub.
Contents¶
Getting Started¶
The only thing you will need is a function that takes a minimum of one
parameter and returns a boolean. The first parameter will be used for
the value to be matched, i.e. the first parameter to assert_that.
The rest of parameters are arbitrary depending on your matcher.
@matcher
def my_function(item, arg1):
# Perform some check that item matches arg1
etc...
It is recommended that you create a docstring for your function. If one exists, it is used as a descriptive string for the case where matching fails. If the string contains string formatting placeholders, they will be used to fill in the matcher functions arguments 1 to n.
In the absence of a docstring, matchmaker will adapt the function name
by replacing underscores with spaces and capitalising the first word.
Usage Examples¶
A few matchers:
from matchmaker import matcher
@matcher
def is_even(item):
return item % 2 == 0
@matcher
def ends_like(item, data, length=3):
"String whose last {1} chars match those for '{0}'"
return item.endswith(data[-length:])
You can then use these in your tests as:
assert_that(number, is_even())
assert_that(word, ends_like(other_word, 4))
Errors will display as:
AssertionError:
Expected: Is even
but: was <3>
AssertionError:
Expected: String whose last 4 chars match those for 'cello'
but: was 'hullo'