`allow_value` matcher is, of course, concerned with setting values on a
particular attribute on a particular record, and then checking that the
record is valid after doing so. That comes with a caveat: if the
attribute is overridden in such a way so that the same value going into
the attribute isn't the same value coming out of it, then `allow_value`
will balk -- it'll say, "I can't do that because that changes how I
work."
That's all well and good, but what the attribute intentionally changes
incoming values? ActiveRecord's typecasting behavior, for instance,
would trigger such an exception. What if the developer needs a way to
get around this? This is where `ignoring_interference_by_writer` comes
into play. You can tack it on to the end of the matcher, and you're free
to go on your way.
So, prior to this commit you could already apply it to `allow_value`,
but now in this commit it also works on any other matcher.
But, one little thing: sometimes using this qualifier isn't going to
work. Perhaps you or something else actually *is* overriding the
attribute to change incoming values in a specific way, and perhaps the
value that comes out makes the record fail validation, and there's
nothing you can do about it. So in this case, even if you're using
`ignoring_interference_by_writer`, we want to inform you about what the
attribute is doing -- what the input and output was. And so we do.
While attempting to add support for `ignoring_interference_by_writer` to
the confirmation matcher, I was noticing that there are two attributes
we are concerned with: the attribute under test, and the confirmation
attribute -- for instance, `password` and `password_confirmation`. The
way that the matcher works, `password_confirmation` is set first on the
record before `password` is set, and then the whole record is validated.
This is fine, but I also noticed that `allow_value` has a specific way
of setting attributes -- not only does it check whether the attribute
being set exists and fail properly if it is does not, but it also
raises a CouldNotSetAttribute error if the attribute changes incoming
values. This logic needs to be performed on both `password_confirmation`
as well as `password`.
With that in mind, `allow_value` now supports a `values_to_preset=`
writer method which allows one to assign additional attributes unrelated
to the one being tested prior to validation. This will be used by the
confirmation matcher in a future commit.
This means that `allow_value` now operates in two steps:
1. Set attributes unrelated to the test, raising an error if any of the
attributes do not exist on the model.
2. Set the attribute under test to one or more values, raising an error
if the attribute does not exist, then running validations on the
record, failing with an appropriate error message if the validations
fail.
Note that the second step is similar to the first, although there are
more things involved. To that end, `allow_value` has been completely
refactored so that the logic for setting and validating attributes
happens in other places. Specifically, the core logic to set an
attribute (and capture the results) is located in a new AttributeSetter
class.
Also, the CouldNotSetAttributeError class has been moved to a namespace
and renamed to AttributeChangedValueError.
Finally, this commit fixes DisallowValueMatcher so that it is the true
opposite of AllowValueMatcher: DVM#matches? calls AVM#does_not_match?
and DVM#does_not_match? calls AVM#matches?.
This is part of a collection of commits that aim to improve failure
messages across the board, in order to make matchers easier to debug
when something goes wrong.
* Have the failure message describe more clearly what the `allow_value`
matcher was trying to do when it failed.
* Make the description of the matcher more readable.
* For each value that `allow_value` sets, use a different Validator
instance. The matcher still changes state as it runs, but a future
commit will refactor this further.
* Merge StrictValidator back into Validator, and remove it. The way that
StrictValidator worked (as a module that was mixed into an instance of
Validator at runtime) was confusing, and there's really no need to
split out the logic anymore.
* Fix or fill in tests involving failure messages and descriptions.
Why:
* Previously, `allow_value` would raise a CouldNotSetAttributeError
if the value being set didn't match the value the attribute had after
being set, but only if the attribute was being changed from nil to
non-nil or non-nil to nil.
* It turns out it doesn't matter which value you're trying to set the
attribute to -- if the attribute rejects that change it's confusing
either way. (In fact, I was recently bit by a case in which I was
trying to validate numericality of an attribute, where the writer
method for that attribute was overridden to ensure that the attribute
always stored a number and never contained non-number characters.
This ended up making the numericality validation useless, of
course -- but it caused confusion because the test acted in a way
I didn't expect.)
To satisfy the above:
* `allow_value` now raises a CouldNotSetAttributeError if the attribute
rejects the value being set in *any* way.
* However, add a `ignoring_interference_by_writer` qualifier so that
it is possible to manually override this behavior.
* Fix tests that are failing now because of this new change:
* Fix tests for allow_value matcher
* Fix tests for numericality matcher
* Remove tests for numericality matcher + integer column
* An integer column will typecast any non-integer value to an
integer.
* Because of the typecasting, our tests for the numericality matcher
against an integer column don't quite work, because we can't
really test what happens when the attribute is set to a
non-integer value. Now that `allow_value` is more strict, we're
getting a CouldNotSetAttributeError when attempting to do so.
* The tests mentioned were originally added to ensure that we are
handling RangeErrors that ActiveRecord used to emit. This doesn't
happen anymore, so the tests aren't necessary anymore either.
* Fix tests for acceptance matcher
* Fix tests for absence matcher
It seems that adding a restriction to allow_value to raise
CouldNotClearAttribute if nil cannot be set on the attribute in question
broke a lot of people's tests. Really the only reason we added this was
for validate_presence_of -- it rescued CouldNotClearAttribute and
re-raised it as CouldNotSetPasswordError, but only for passwords and
only if has_secure_password was being used. So, I've figured out another
way of performing this check inside of validate_presence_of only to
prevent tests that have nothing to do with from breaking unnecessarily.
The methods failure_message_for_should and failure_message_for_should_not
have been updated to failure_message and failure_message_negated respectively.
Alias to the old methods to remain backwards compatibility with RSpec 2.
Duncan Stuart