DEV: introduces coding style spec (#7615)

spec/integrity/coding_style_spec.rb

@@ -0,0 +1,35 @@
+# frozen_string_literal: true
+
+def list_files(base_dir, pattern = '*')
+  Dir[File.join("#{base_dir}", pattern)]
+end
+
+def list_js_files(base_dir)
+  list_files(base_dir, '**/*.es6')
+end
+
+def grep_files(files, regex)
+  files.select { |file| grep_file(file, regex) }
+end
+
+def grep_file(file, regex)
+  lines = File.open(file).grep(regex)
+  lines.count > 0 ? file : nil
+end
+
+describe 'Coding style' do
+  describe 'Javascript' do
+    it 'prevents this.get("foo") pattern' do
+      js_files = list_js_files('app/assets/javascripts')
+      offenses = grep_files(js_files, /this\.get\("\w+"\)/)
+
+      expect(offenses).to be_empty, <<~MSG
+        Do not use this.get("foo") accessor for single property, instead
+        prefer to use this.foo
+
+        Offenses:
+        #{offenses.join("\n")}
+      MSG
+    end
+  end
+end