(MODULES-3958) use rspec-mock and add coverage

spec/spec_helper_local.rb

@@ -0,0 +1,28 @@
+if ENV['COVERAGE'] == 'yes'
+  require 'simplecov'
+  require 'simplecov-console'
+  require 'codecov'
+
+  SimpleCov.formatters = [
+    SimpleCov::Formatter::HTMLFormatter,
+    SimpleCov::Formatter::Console,
+    SimpleCov::Formatter::Codecov,
+  ]
+  SimpleCov.start do
+    track_files 'lib/**/*.rb'
+
+    add_filter '/spec'
+
+    # do not track vendored files
+    add_filter '/vendor'
+    add_filter '/.vendor'
+
+    # do not track gitignored files
+    # this adds about 4 seconds to the coverage check
+    # this could definitely be optimized
+    add_filter do |f|
+      # system returns true if exit status is 0, which with git-check-ignore means file is ignored
+      system("git check-ignore --quiet #{f.filename}")
+    end
+  end
+end