should_dsl 1.1

Should assertions in Python as clear and readable as possible

The goal of Should DSL is to write should expectations in Python as clear and readable as possible.

It would be good to be as close as:

SOME_VALUE should be equal to ANOTHER VALUE
or
SOME_EXCEPTION should be thrown by SOME_CALLABLE
or
SOME_VALUE should not be into SOME_CONTAINER

For using this DSL, you need to import all the module’s namespace, as:

from should_dsl import *

For example:

1  |should_be.equal_to| 1     # will be true
'should' |should_have| 'oul'  # will also be true
3 |should_be.into| (0, 1, 2)  # will raise a ShouldNotSatisfied exception

The equal_to matcher verifies object equality. If you want to ensure identity, you must use should_be with no matcher:

2 |should_be| 2

A nice example of exceptions would be:

def raise_zerodivisionerror():
    return 1/0
ZeroDivisionError |should_be.thrown_by| raise_zerodivisionerror

Both should_have and should_be have versions for negation:

2 |should_not_be.into| [1, 3, 5]    # will be true
'should' |should_not_have| 'oul'    # will raise a ShouldNotSatisfied exception

Extending the DSL with custom matchers is easy:

@matcher
def the_square_root_of():
    import math
    return (lambda x, y: x == math.sqrt(y), "%s is %sthe square root of %s")

3 |should_be.the_square_root_of| 9    # will be true
4 |should_be.the_square_root_of| 9    # will raise a ShouldNotSatisfiedException

should-dsl is unittest-compatible, so, on a unittest test case, failures on should expectations will result on unittest failures, not errors.