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Testing Image Geometry Detection and EXIF Handling in Paperclip

This test suite validates the GeometryDetector functionality in Paperclip, focusing on image dimension extraction and orientation handling. The tests ensure accurate parsing of image metadata and proper handling of EXIF orientation data.

Test Coverage Overview

The test suite covers essential image geometry detection capabilities in Paperclip.

Key areas tested include:

Basic image dimension extraction
EXIF orientation detection
Configurable EXIF orientation handling

Edge cases focus on different image formats and orientation scenarios, with integration points to the GeometryParser component.

Implementation Analysis

The testing approach uses RSpec’s stubbing capabilities to isolate GeometryDetector functionality from GeometryParser dependencies.

Implementation patterns include:

Fixture-based test data
Stub method chaining
Configuration state management
Clean test setup and teardown

Technical Details

Testing tools and setup:

RSpec testing framework
Stub/mock functionality
Fixture file handling
Configuration management through Paperclip.options

Best Practices Demonstrated

The test suite demonstrates strong testing practices through isolated unit tests and proper test organization.

Notable practices include:

Clear test case separation
Proper setup/teardown patterns
Configuration state restoration
Focused test scenarios

thoughtbot/paperclip

spec/paperclip/geometry_detector_spec.rb

            
require 'spec_helper'

describe Paperclip::GeometryDetector do
  it 'identifies an image and extract its dimensions' do
    Paperclip::GeometryParser.stubs(:new).with("434x66,").returns(stub(make: :correct))
    file = fixture_file("5k.png")
    factory = Paperclip::GeometryDetector.new(file)

    output = factory.make

    expect(output).to eq :correct
  end

  it 'identifies an image and extract its dimensions and orientation' do
    Paperclip::GeometryParser.stubs(:new).with("300x200,6").returns(stub(make: :correct))
    file = fixture_file("rotated.jpg")
    factory = Paperclip::GeometryDetector.new(file)

    output = factory.make

    expect(output).to eq :correct
  end

  it 'avoids reading EXIF orientation if so configured' do
    begin
      Paperclip.options[:use_exif_orientation] = false
      Paperclip::GeometryParser.stubs(:new).with("300x200,1").returns(stub(make: :correct))
      file = fixture_file("rotated.jpg")
      factory = Paperclip::GeometryDetector.new(file)

      output = factory.make

      expect(output).to eq :correct
    ensure
      Paperclip.options[:use_exif_orientation] = true
    end
  end
end