Rewriting and refactoring Squib sample test

spec/samples/samples_regression_spec.rb

@@ -2,41 +2,70 @@ require 'spec_helper'
 require 'squib'
 require 'pp'
 
-describe Squib do
+describe "Squib samples" do
+  let(:samples_dir) { "#{File.expand_path(File.dirname(__FILE__))}/../../samples/" }
 
-  context 'samples' do
-    it 'should execute with no errors' do
-      allow(ProgressBar).to receive(:create).and_return(Squib::DoNothing.new)
-      samples = File.expand_path('../../samples', File.dirname(__FILE__))
-      Dir["#{samples}/**/*.rb"].each do |sample|
-        Dir.chdir(samples) do #to save to _output
-          load sample
-        end
-      end
+  around(:each) do |example|
+    Dir.chdir(samples_dir) do
+      example.run
     end
+  end
 
-    # it 'did not change against regression logs' do
-    #   samples = File.expand_path('../../samples', File.dirname(__FILE__))
-    #   Dir["#{samples}/**/*.rb"].each do |sample|
-    #     sample_name = File.basename(sample)
-    #     header = "=== #{sample_name} ===\n"
-    #     Dir.chdir(samples) do #to save to _output
-    #       strio = StringIO.new
-    #       strio << header
-    #       mock_cairo(strio)
-    #       load sample
-    #       test_file_str = ""
-    #       # Use this to overwrite the regression with current state
-    #       # Use ONLY temporarily after you are happy with the new sample log
-    #       # File.open(sample_regression_file(sample_name), 'w+') do |f|
-    #       #   f.write(strio.string.force_encoding("UTF-8")) # write back out to expected file
-    #       # end
-    #       test_file_str << File.open(sample_regression_file(sample_name)).read.force_encoding("UTF-8")
-    #       expect(strio.string).to eq(test_file_str)
-    #     end
-    #   end
-    # end
+  it 'should execute with no errors' do
+    allow(ProgressBar).to receive(:create).and_return(Squib::DoNothing.new)
+    Dir["#{samples_dir}/**/*.rb"].each do |sample|
+      load sample
+    end
+  end
 
+  # This test could use some explanation
+  # Much of the development of Squib has been sample-driven. Every time I want
+  # new syntax or feature, I write a sample, get it working, and then write
+  # tests for boundary cases in the unit tests.
+  #
+  # This makes documentation much easier and example-driven.
+  # ...but I want to use those samples for regression & integration tests too.
+  #
+  # The above test is a good smoke test, but it just looks for exceptions.
+  # What this set of tests do is run the samples again, but mocking out Cairo,
+  # Pango, RSVG, and any other dependencies. We log those API calls and store
+  # them in a super-verbose string. We compare our runs against what happened
+  # before.
+  #
+  # Thus, if we ever change anything that results in a ANY change to our
+  # regression logs, then these tests will fail. If it's SURPRISING, then we
+  # caught an integration bug. If it's not, just update and overwrite the logs.
+  #
+  # So it's understood that you should have to periodically enable the
+  # overwrite_sample method below to store the new regression log. Just make
+  # sure you inspect the change and make sure it makes sense with the change
+  # you made to the samples or Squib.
+  %w( hello_world.rb
+      autoscale_font.rb
+      layouts.rb
+      save_pdf.rb
+      custom_config.rb
+      load_images.rb
+      basic.rb
+      cairo_access.rb
+      draw_shapes.rb
+      text_options.rb
+      colors.rb
+      excel.rb
+      portrait-landscape.rb
+      tgc_proofs.rb
+      ranges.rb
+      units.rb
+  ).each do |sample|
+    it "has not changed for #{sample}" do
+      log = StringIO.new
+      mock_cairo(log)
+      load sample
+      # overwrite_sample(sample, log) # Use TEMPORARILY once happy with the new sample log
+      test_file_str = File.open(sample_regression_file(sample))
+                          .read.force_encoding("UTF-8")
+      expect(log.string).to eq(test_file_str)
+    end
   end
 
 end

spec/spec_helper.rb

@@ -19,15 +19,27 @@ def layout_file(str)
   "#{File.expand_path(File.dirname(__FILE__))}/data/layouts/#{str}"
 end
 
+def sample_file(file)
+  "#{File.expand_path(File.dirname(__FILE__))}/../samples/#{file}"
+end
+
 def sample_regression_file(file)
   "#{File.expand_path(File.dirname(__FILE__))}/data/samples/#{file}.txt"
 end
 
+def overwrite_sample(sample_name, log)
+  # Use this to overwrite the regression with current state
+  File.open(sample_regression_file(sample_name), 'w+') do |f|
+    f.write(log.string.force_encoding("UTF-8")) # write back out to expected file
+  end
+end
+
 def scrub_hex(str)
   str.gsub(/0x\w{1,8}/,'')
      .gsub(/ptr=\w{1,8}/,'')
      .gsub(/#<Pango::FontDescription:.*>/,'')
-     .gsub(/Handle:\w{1,8}/,'Handle')
+     .gsub(/#<Cairo::ImageSurface:.*>/,'ImageSurface')
+     .gsub(/#<RSVG::Handle.*>/,'RSVG::Handle')
      .gsub(/RGB:\w{1,8}/,'RGB:')
 end