I think I would rather prefer to copy the methods into this describe block instead of extracting them into a module. The reason is that ContextMatcher and ComparisonMatcher have two separate requirements on which records they work with. ComparisonMatcher needs a record that has validates_numericality_of defined on it because it is designed to be used with ValidateNumericalityOfMatcher. ContextMatcher on the other hand needs a record that has a validation defined on it that supports the `:on` option (because it's designed to be used with matchers which support `:on`).

So instead of a module, what if within this describe block and the describe block for ComparisonMatcher, you did something like this: 

* For ComparisonMatcher have two methods called `validating_numericality` (receiving options like `greater_than: 2`) and `validating_nothing`.
* For ContextMatcher have two methods called `validating_something_in_context` (which would receive a context like `:customizable`) and `validating_nothing`.