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Testing Multiple Attributes Iterator Validation in Grape Framework

This test suite validates the MultipleAttributesIterator class in Grape’s validation system, focusing on parameter handling and iteration behavior. It ensures proper handling of both hash and array parameters, along with special cases like empty optional values.

Test Coverage Overview

The test suite provides comprehensive coverage of the MultipleAttributesIterator’s #each method functionality.

Key areas tested include:

Hash parameter processing
Array parameter iteration
Empty optional value handling
Parameter scope validation

The tests verify both single and multiple parameter scenarios, ensuring robust parameter iteration functionality.

Implementation Analysis

The testing approach utilizes RSpec’s behavior-driven development patterns with context-specific test cases. It employs subject/let blocks for clean test setup and uses doubles for API class simulation.

Technical implementation features:

RSpec block syntax for expectations
Mock objects for validator simulation
Yield argument testing
Context-based test organization

Technical Details

Testing tools and configuration:

RSpec testing framework
Grape API framework integration
Mock objects and doubles
ParamsScope configuration
Validator attribute setup

Best Practices Demonstrated

The test suite exemplifies several testing best practices in Ruby and RSpec.

Notable practices include:

Clear context separation
Isolated test cases
Proper mock object usage
Consistent naming conventions
Focused test scenarios

ruby-grape/grape

spec/grape/validations/multiple_attributes_iterator_spec.rb

            
# frozen_string_literal: true

describe Grape::Validations::MultipleAttributesIterator do
  describe '#each' do
    subject(:iterator) { described_class.new(validator, scope, params) }

    let(:scope) { Grape::Validations::ParamsScope.new(api: Class.new(Grape::API)) }
    let(:validator) { double(attrs: %i[first second third]) }

    context 'when params is a hash' do
      let(:params) do
        { first: 'string', second: 'string' }
      end

      it 'yields the whole params hash without the list of attrs' do
        expect { |b| iterator.each(&b) }.to yield_with_args(params)
      end
    end

    context 'when params is an array' do
      let(:params) do
        [{ first: 'string1', second: 'string1' }, { first: 'string2', second: 'string2' }]
      end

      it 'yields each element of the array without the list of attrs' do
        expect { |b| iterator.each(&b) }.to yield_successive_args(params[0], params[1])
      end
    end

    context 'when params is empty optional placeholder' do
      let(:params) { [Grape::DSL::Parameters::EmptyOptionalValue] }

      it 'does not yield it' do
        expect { |b| iterator.each(&b) }.to yield_successive_args
      end
    end
  end
end