Add spec to ensure runtime isn't incremented twice

Adds a spec around `Lograge::ActiveRecordLogSubscriber#sql` to ensure
that when the config option `keep_default_active_record_log` is set, the
`ActiveRecord::LogSubscriber.runtime` isn't incremented. This keeps
lograge from double-counting the total duration for database calls.

spec/lograge/active_record_log_subscriber_spec.rb

@@ -0,0 +1,37 @@
+# frozen_string_literal: true
+
+RSpec.describe Lograge::ActiveRecordLogSubscriber do
+  describe '#sql' do
+    subject(:log_subscriber) { described_class.new }
+    let(:event) { instance_double('ActiveSupport::Notification::Event.new', duration: 20, payload: {}) }
+    let(:rails) { double('rails') }
+    let(:ar_log_subscriber) { double('ActiveRecord::LogSubscriber', runtime: 100) }
+
+    before do
+      stub_const('Rails', rails)
+      stub_const('ActiveRecord::LogSubscriber', ar_log_subscriber)
+      Lograge::Sql.extract_event = proc {}
+    end
+
+    context 'with keep_default_active_record_log not set' do
+      before do
+        allow(Rails).to receive_message_chain('application.config.lograge_sql.keep_default_active_record_log') { nil }
+      end
+      it 'adds duration to ActiveRecord::LogSubscriber runtime' do
+        expect(ar_log_subscriber).to receive(:runtime=).with(120)
+
+        log_subscriber.sql(event)
+      end
+    end
+    context 'with keep_default_active_record_log set to true' do
+      before do
+        allow(Rails).to receive_message_chain('application.config.lograge_sql.keep_default_active_record_log') { true }
+      end
+      it 'does not add duration to ActiveRecord::LogSubscriber runtime' do
+        expect(ar_log_subscriber).to_not receive(:runtime=)
+
+        log_subscriber.sql(event)
+      end
+    end
+  end
+end

spec/spec_helper.rb

@@ -7,6 +7,7 @@
 require 'delegate'
 require 'lograge'
 require 'lograge/sql'
+require 'lograge/active_record_log_subscriber'
 
 RSpec.configure do |config| # rubocop:disable Style/SymbolProc
   config.disable_monkey_patching!