Module: Cucumber::Core::Filter

Defined in:
lib/cucumber/core/filter.rb

Overview

Filters process test cases.

Each filter must respond to the following protocol:

  • with_receiver(new_receiver)
  • test_case(test_case, &describe_test_steps)
  • done

The with_receiver method is used to assemble the filters into a chain. It should return a new instance of the filter with the receiver attribute set to the new receiver. The receiver will also respond to the filter protocol.

When a test_case message is received, the filter can choose to:

  1. pass the test_case directly to its receiver (no-op)
  2. pass a modified copy of the test_case to its receiver
  3. not pass the test_case to its receiver at all

Finally, the done message is sent. A filter should pass this message directly to its receiver.

Class Method Summary collapse

Class Method Details

.new(*attributes, &block) ⇒ Object

Utility method for quick construction of filter classes.

The attribute names passed to the Filter constructor will become private attributes of your filter class.

Examples:

Example usage:


class BlankingFilter < Filter.new(:name_to_blank, :receiver)
  def test_case(test_case)
    if name_to_blank == test_case.name
      test_case.with_steps([]).describe_to(receiver)
    else
      test_case.describe_to(receiver)
    end
  end
end


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# File 'lib/cucumber/core/filter.rb', line 42

def self.new(*attributes, &block)
  attributes << :receiver

  result = Class.new do
    attr_reader(*attributes)
    private(*attributes)

    define_method(:initialize) do |*args|
      attributes.zip(args) do |name, value|
        instance_variable_set("@#{name}".to_sym, value)
      end
    end

    def test_case(test_case)
      test_case.describe_to receiver
      self
    end

    def done
      receiver.done
      self
    end

    define_method(:with_receiver) do |new_receiver|
      args = attributes.map { |name|
        instance_variable_get("@#{name}".to_sym)
      }
      args[-1] = new_receiver
      self.class.new(*args)
    end

  end

  if block
    Class.new(result, &block)
  else
    result
  end
end