Issue 498: Integrate the Churn Gem and Write a Learning Test to Understand Parts of the Interface RubyCritic Cares About

rubycritic.gemspec

@@ -30,6 +30,7 @@ Gem::Specification.new do |spec|
   spec.executables   = `git ls-files -- bin/*`.split("\n").map { |f| File.basename(f) }
   spec.require_path  = 'lib'
 
+  spec.add_dependency 'churn'
   spec.add_dependency 'flay', '~> 2.13'
   spec.add_dependency 'flog', '~> 4.7'
   spec.add_dependency 'launchy', '>= 2.5.2'

test/lib/rubycritic/learning/churn_gem_learning_test.rb

@@ -0,0 +1,26 @@
+# frozen_string_literal: true
+
+require 'test_helper'
+require 'churn'
+require 'churn/calculator'
+require 'byebug'
+describe "churn gem's Churn" do
+  it 'computes how many times a file was changed' do
+    config = {
+      report: false,
+      start_date: '6 years ago',
+      minimum_churn_count: 1
+    }
+    Churn::GitAnalyzer.stubs(:supported?).returns(true)
+    churn_calculator = Churn::ChurnCalculator.new(config)
+    churn_calculator.stubs(:parse_log_for_changes).returns([['file.rb', 4], ['less.rb', 1]])
+    churn_calculator.stubs(:parse_log_for_revision_changes).returns(['revision-git-sha'])
+
+    report = churn_calculator.report(false)
+
+    changes = report[:churn][:changes].first
+
+    assert_equal 'file.rb', changes[:file_path]
+    assert_predicate changes[:times_changed], :positive?
+  end
+end