Back to Repositories

Testing Parameter Modification Behavior in Grape API Endpoints

This test suite validates parameter modification behavior in Grape API endpoints, focusing on maintaining parameter default values across multiple requests. It ensures that modifying parameter values during request processing doesn’t affect subsequent requests.

Test Coverage Overview

The test suite provides comprehensive coverage of parameter value modification scenarios in Grape API endpoints.

Tests default parameter persistence across multiple requests
Verifies parameter modification isolation between requests
Validates custom parameter value handling
Ensures parameter state reset between requests

Implementation Analysis

The testing approach uses RSpec to simulate multiple HTTP GET requests to a Grape API endpoint. It implements a namespace with an optional parameter ‘foo’ that has a default value, and tests the parameter’s behavior when its value is modified during request processing.

Uses Grape’s parameter definition DSL
Implements string manipulation on parameter values
Validates response status and body content

Technical Details

Testing Framework: RSpec
API Framework: Grape
Test Environment: Rack::Test
Parameter Type: Optional with default value
HTTP Method: GET
Response Validation: Status code and body content

Best Practices Demonstrated

The test suite exemplifies several testing best practices for API endpoint validation.

Isolated test context using subject blocks
Clear test case organization with descriptive contexts
Consistent request-response validation pattern
Multiple assertion points to ensure complete validation
Proper setup and teardown management

ruby-grape/grape

spec/grape/api/parameters_modification_spec.rb

            
# frozen_string_literal: true

describe Grape::Endpoint do
  subject { Class.new(Grape::API) }

  def app
    subject
  end

  before do
    subject.namespace :test do
      params do
        optional :foo, default: +'-abcdef'
      end
      get do
        params[:foo].slice!(0)
        params[:foo]
      end
    end
  end

  context 'when route modifies param value' do
    it 'param default should not change' do
      get '/test'
      expect(last_response.status).to eq 200
      expect(last_response.body).to eq 'abcdef'

      get '/test'
      expect(last_response.status).to eq 200
      expect(last_response.body).to eq 'abcdef'

      get '/test?foo=-123456'
      expect(last_response.status).to eq 200
      expect(last_response.body).to eq '123456'

      get '/test'
      expect(last_response.status).to eq 200
      expect(last_response.body).to eq 'abcdef'
    end
  end
end