Added EachBatch for iterating tables in batchesactive-record-each-batch

This module provides a class method called `each_batch` that can be used
to iterate tables in batches in a more efficient way compared to Rails'
`in_batches` method. This commit also includes a RuboCop cop to
blacklist the use of `in_batches` in favour of this new method.

1 files changed, 19 insertions, 0 deletions

diff --git a/spec/rubocop/cop/in_batches_spec.rb b/spec/rubocop/cop/in_batches_spec.rb
new file mode 100644
index 00000000000..072481984c6
--- /dev/null
+++ b/spec/rubocop/cop/in_batches_spec.rb
@@ -0,0 +1,19 @@
+require 'spec_helper'
+require 'rubocop'
+require 'rubocop/rspec/support'
+require_relative '../../../rubocop/cop/in_batches'
+
+describe RuboCop::Cop::InBatches do
+  include CopHelper
+
+  subject(:cop) { described_class.new }
+
+  it 'registers an offense when in_batches is used' do
+    inspect_source(cop, 'foo.in_batches do; end')
+
+    aggregate_failures do
+      expect(cop.offenses.size).to eq(1)
+      expect(cop.offenses.map(&:line)).to eq([1])
+    end
+  end
+end