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Testing Helper Module Implementation in ruby-grape/grape

This test suite examines the helper functionality in the Grape DSL (Domain Specific Language) implementation. It verifies the proper inclusion and behavior of helper modules, parameter validation, and inheritance patterns in Grape API classes.

Test Coverage Overview

The test suite provides comprehensive coverage of the Grape::DSL::Helpers module functionality:

Helper module addition and integration
Multiple module support and stacking
Boolean parameter type handling
Inheritance behavior in child classes
Parameter validation scenarios

Implementation Analysis

The testing approach uses RSpec to verify helper module behavior through multiple contexts:

The tests employ class instantiation with module inclusion, lambda procedures for dynamic method definition, and mock expectations to verify correct namespace stacking. Specific attention is given to module inheritance and parameter validation patterns.

Technical Details

Testing infrastructure includes:

RSpec as the testing framework
Mock objects and expectations
Dynamic class generation
Module extension patterns
Namespace stackable helpers
Boolean type validation

Best Practices Demonstrated

The test suite exhibits several testing best practices:

Implementation includes proper isolation of test cases, clear context separation, and comprehensive edge case coverage. The code demonstrates effective use of RSpec’s let blocks, subject definition, and expectation syntax while maintaining clear test organization and readability.

ruby-grape/grape

spec/grape/dsl/helpers_spec.rb

            
# frozen_string_literal: true

describe Grape::DSL::Helpers do
  subject { dummy_class }

  let(:dummy_class) do
    Class.new do
      include Grape::DSL::Helpers

      def self.mods
        namespace_stackable(:helpers)
      end

      def self.first_mod
        mods.first
      end
    end
  end

  let(:proc) do
    lambda do |*|
      def test
        :test
      end
    end
  end

  describe '.helpers' do
    it 'adds a module with the given block' do
      expect(subject).to receive(:namespace_stackable).with(:helpers, kind_of(Grape::DSL::Helpers::BaseHelper)).and_call_original
      expect(subject).to receive(:namespace_stackable).with(:helpers).and_call_original
      subject.helpers(&proc)

      expect(subject.first_mod.instance_methods).to include(:test)
    end

    it 'uses provided modules' do
      mod = Module.new

      expect(subject).to receive(:namespace_stackable).with(:helpers, kind_of(Grape::DSL::Helpers::BaseHelper)).and_call_original.twice
      expect(subject).to receive(:namespace_stackable).with(:helpers).and_call_original
      subject.helpers(mod, &proc)

      expect(subject.first_mod).to eq mod
    end

    it 'uses many provided modules' do
      mod  = Module.new
      mod2 = Module.new
      mod3 = Module.new

      expect(subject).to receive(:namespace_stackable).with(:helpers, kind_of(Grape::DSL::Helpers::BaseHelper)).and_call_original.exactly(4).times
      expect(subject).to receive(:namespace_stackable).with(:helpers).and_call_original.exactly(3).times

      subject.helpers(mod, mod2, mod3, &proc)

      expect(subject.mods).to include(mod)
      expect(subject.mods).to include(mod2)
      expect(subject.mods).to include(mod3)
    end

    context 'with an external file' do
      let(:boolean_helper) do
        Module.new do
          extend Grape::API::Helpers

          params :requires_toggle_prm do
            requires :toggle_prm, type: Boolean
          end
        end
      end

      it 'sets Boolean as a Grape::API::Boolean' do
        subject.helpers boolean_helper
        expect(subject.first_mod::Boolean).to eq Grape::API::Boolean
      end
    end

    context 'in child classes' do
      let(:base_class) do
        Class.new(Grape::API) do
          helpers do
            params :requires_toggle_prm do
              requires :toggle_prm, type: Integer
            end
          end
        end
      end

      let(:api_class) do
        Class.new(base_class) do
          params do
            use :requires_toggle_prm
          end
        end
      end

      it 'is available' do
        expect { api_class }.not_to raise_exception
      end
    end
  end
end