test: add specs for non-rgb image processing

.rspec

@@ -1,3 +1,2 @@
 --color
---format progress
 --require spec_helper

bin/benchmark-full

@@ -15,7 +15,7 @@ inputs = [
   {
     path: 'tmp/high-res-small-size-16000x11000px.jpg',
     options: { 'crop' => '815,850,14909,10005', 'straighten' => 0.5, 'gamma' => 0.85 },
-    description: 'Huge, pixelised grayscale gradient'
+    description: 'Huge, pixelised greyscale gradient'
   },
   {
     path: 'tmp/spider-8288816.jpg',

spec/colour_helper.rb

@@ -1,27 +1,27 @@
 # frozen_string_literal: true
 
 module ColourHelper
-  def generate_test_image(at_file_path, width = 600, height = 300)
-    system(
-      'convert',
-      '-size',
-      "#{width}x#{height}",
-      '-seed',
-      '5432',
-      'plasma:red-blue',
-      'pattern:checkerboard', '-gravity', 'center', '-geometry', "+#{width * 3 / 4},+0", '-composite',
-      at_file_path
-    )
+  def generate_test_image_plasma_checkers(at_file_path, width: 600, height: 300)
+    fill = [
+      ['plasma:red-blue'],
+      ['pattern:checkerboard', '-gravity', 'center', '-geometry', "+#{width * 3 / 4},+0", '-composite']
+    ]
+    generate_test_image(at_file_path, fill: fill, width: width, height: height)
   end
 
-  def solid_colour_image(width, height, colour = 0x000000ff)
-    pb = GdkPixbuf::Pixbuf.new(colorspace: GdkPixbuf::Colorspace::RGB,
-                               has_alpha: false,
-                               bits_per_sample: 8,
-                               width: width,
-                               height: height)
-    pb.fill!(colour)
-    pb
+  def generate_test_image_greyscale(at_file_path, width: 600, height: 300)
+    generate_test_image(at_file_path, fill: 'gradient:white-black', width: width, height: height)
+  end
+
+  def generate_test_image(at_file_path, fill:, width: 600, height: 300)
+    fill = Array(fill).flatten
+
+    generate_image_options = ['convert', '-size', "#{width}x#{height}", '-seed', '5432', *fill, at_file_path]
+    system(*generate_image_options) || raise("Failed to generate image.\nCommand: #{generate_image_options.join(' ')}")
+  end
+
+  def generate_test_image_solid(at_file_path, width: 600, height: 300, colour: '#000000')
+    generate_test_image(at_file_path, width: width, height: height, fill: "canvas:#{colour}")
   end
 
   def crude_average_colour(pixbuf)

spec/morandi_spec.rb

@@ -17,6 +17,9 @@
   let(:processed_image_type) { processed_image_info[0].name }
   let(:processed_image_width) { processed_image_info[1] }
   let(:processed_image_height) { processed_image_info[2] }
+  let(:generate_image) do
+    generate_test_image_plasma_checkers(file_in, width: original_image_width, height: original_image_height)
+  end
 
   before(:all) do
     FileUtils.mkdir_p('sample')
@@ -27,12 +30,15 @@
   end
 
   before do
-    generate_test_image(file_in, original_image_width, original_image_height) unless File.exist?(file_in)
+    next if File.exist?(file_in)
+
+    generate_image
   end
 
   after do |ex|
-    add_to_visual_report(ex, files = Dir['sample/*'])
-    FileUtils.rm_rf(files)
+    test_files = Dir['sample/*']
+    add_to_visual_report(ex, (test_files + [file_in]).uniq)
+    FileUtils.rm_rf(test_files)
   end
 
   after(:all) do
@@ -453,6 +459,31 @@
         end
       end
     end
+
+    context 'with a non-rgb image' do
+      let(:generate_image) do
+        generate_test_image_greyscale(file_in, width: original_image_width, height: original_image_height)
+      end
+
+      it 'changes greyscale image to srgb' do
+        expect(file_in).to match_colourspace('gray') # Testing a setup to protect from a hidden regression
+        process_image
+
+        expect(file_out).to match_colourspace('srgb')
+      end
+
+      # Colour filters implementation operates on RGB-based constants, thus a dedicated test
+      context 'with colour filter' do
+        let(:options) { super().merge('fx' => 'sepia') }
+
+        it 'creates a valid, srgb image' do
+          process_image
+
+          expect(file_out).to match_reference_image('greyscale-with-sepia')
+          expect(file_out).to match_colourspace('srgb')
+        end
+      end
+    end
   end
 
   context 'pixbuf processor' do
@@ -486,7 +517,7 @@
       let(:icc_height) { 400 }
 
       before do
-        generate_test_image(icc_path, icc_width, icc_height)
+        generate_test_image_plasma_checkers(icc_path, width: icc_width, height: icc_height)
       end
 
       it 'should use a file at this location as the input' do
@@ -516,7 +547,7 @@
       let(:icc_height) { 400 }
 
       before do
-        generate_test_image(icc_path, icc_width, icc_height)
+        generate_test_image_plasma_checkers(icc_path, width: icc_width, height: icc_height)
       end
 
       it 'should ignore the file at this path' do
@@ -547,7 +578,10 @@
       end
 
       context 'with a gray image and invalid spots' do
-        let(:file_arg) { solid_colour_image(800, 800, 0x666666ff) }
+        let(:file_in) { 'sample/sample.jpg' }
+        let(:original_image_width) { 800 }
+        let(:original_image_height) { 800 }
+        let(:generate_image) { generate_test_image_solid(file_in, width: 800, height: 800, colour: '#666666') }
         let(:options) { { 'redeye' => [[540, 650], [-100, 100]] } }
 
         it 'should not break or corrupt the image' do
@@ -556,9 +590,9 @@
           expect(File).to exist(file_out)
           expect(processed_image_type).to eq('jpeg')
 
-          expect(crude_average_colour(file_arg.subpixbuf(505, 605, 100, 100))).to be_greyish
-          expect(crude_average_colour(GdkPixbuf::Pixbuf.new(file: file_out).subpixbuf(505, 605, 100,
-                                                                                      100))).to be_greyish
+          expect(crude_average_colour(GdkPixbuf::Pixbuf.new(file: file_in).subpixbuf(505, 605, 100, 100))).to be_greyish
+          expect(crude_average_colour(GdkPixbuf::Pixbuf.new(file: file_out).subpixbuf(505, 605, 100, 100)))
+            .to be_greyish
         end
       end
     end

spec/spec_helper.rb

@@ -19,14 +19,25 @@
 require 'super_diff/rspec'
 require 'pry'
 
-require 'support/match_reference_image'
+Dir['spec/support/**/*.rb'].each { |f| require "./#{f}" }
+
 require_relative 'visual_report_helper'
 require_relative 'colour_helper'
 
 RSpec.configure do |config|
   config.run_all_when_everything_filtered = true
   config.filter_run :focus
 
+  # Many RSpec users commonly either run the entire suite or an individual
+  # file, and it's useful to allow more verbose output when running an
+  # individual spec file.
+  if config.files_to_run.one?
+    # Use the documentation formatter for detailed output,
+    # unless a formatter has already been configured
+    # (e.g. via a command-line flag).
+    config.default_formatter = 'doc'
+  end
+
   # Run specs in random order to surface order dependencies. If you find an
   # order dependency and want to debug it, you can fix the order by providing
   # the seed, which is printed after each run.

spec/support/match_colourspace.rb

@@ -0,0 +1,21 @@
+# frozen_string_literal: true
+
+require 'open3'
+
+# For testing that under a given path resides an image with desired colourspace.
+# The colourspace is currently extracted using imagemagick's `identify`, resulting in values like 'gray' or 'srgb'
+# According to docs (https://www.imagemagick.org/script/escape.php), it may include number of channels and meta channels
+RSpec::Matchers.define :match_colourspace do |expected_colourspace|
+  match do |tested_path|
+    raise(ArgumentError, "path #{tested_path} is not a file") unless File.file?(tested_path)
+
+    @colourspace, status = Open3.capture2('identify', '-format', '%[channels]', tested_path)
+    raise "Failed to read colorspace of #{tested_path}" unless status.success?
+
+    @colourspace == expected_colourspace
+  end
+
+  failure_message do
+    "Colourspaces don't match. Expected: #{expected_colourspace}, got: #{@colourspace}"
+  end
+end

spec/support/match_reference_image.rb

@@ -82,7 +82,9 @@ def debug_data
   end
 
   match do |tested_path|
-    if File.file?(tested_path) && !File.file?(reference_path)
+    raise ArgumentError, "Provided path is not a file: #{tested_path}" unless File.file?(tested_path)
+
+    unless File.file?(reference_path)
       debug_data.expose_from(tested_path: tested_path, file_type: file_type)
       return false
     end