Proc argument matcher matches all or nothing

[ml]

I am not able to use proc argument matcher to match just argument among a few:

mock(ESP::Mail).deliver("kiszonka", with { |message| message[:to] == "stefan@kiszonka.com" })

ESP::Mail.deliver "kiszonka", to: "stefan@kiszonka.com"

doesn't work and the matcher never gets called, while

mock(ESP::Mail).deliver(with { |template_name, message| 
 template_name == "kiszonka" && message[:to] == "stefan@kiszonka.com" })

ESP::Mail.deliver "kiszonka", to: "stefan@kiszonka.com"

works. Is it desired behavior and I'm just doing something wrong?

[psyho]

The with matcher is used to check all of the arguments together, that's why the second version works.

At the moment we don't have a single argument matcher with a proc, but it's very easy to add yourself, since the matchers are essentially just objects with overridden equality checks:

class Matches
  def initialize(&block)
    @block = block
  end

  def ==(argument)
    @block.call(argument)
  end
end

def matches(&block)
  Matches.new(&block)
end

and you will be able to use it like this:

mock(ESP::Mail).deliver("kiszonka", matches { |message| message[:to] == "stefan@kiszonka.com" })

We'll add something like this in the next version.