Resolutions¶
Resolutions provide an expected answer to questions. They are the second half of test assertions in ScreenPy: the “expected value”. (The first half are Questions, if you missed that page.)
Using Resolutions¶
Like Questions,
you probably will not use
a resolution directly.
You will typically pass a resolution
along with a question
into your actor’s
should_see_the() method:
from screenpy.questions import Text
from screenpy.resolutions import ReadsExactly
from ..user_interface.homepage import WELCOME_MESSAGE
Perry.should_see_the((Text.of_the(WELCOME_MESSAGE), ReadsExactly("Welcome!")))
In that line of code,
ReadsExactly is returning
a PyHamcrest matcher.
It will be evaluated later
as should_see_the() does its job.
If the expected value
(“Welcome!”)
matches the actual value
retrieved by our question,
bravo!
Our test passes.
If they do not match,
boo!
Our test fails.
Writing New Resolutions¶
Resolutions are really
just an abstraction barrier
for the truly excellent
PyHamcrest library.
To add your own resolutions,
create your resolution class
by inheriting from the
BaseResolution class.
All you need to provide in your resolution
is a line class property,
which is just a human readable string
for the log,
and then to define
the __init__ method.
The custom Resolution’s
__init__ method
will need to set
the expected value,
and instantiate the PyHamcrest matcher
that your resolution is masking.
For several examples,
see the documentation
of the Provided Resolutions below.