Add specs for Sequel connection case

Author: ssnickolay

spec/features/connections_spec.rb

@@ -5,6 +5,17 @@ def execute(query, context = {})
 end
 
 RSpec.describe 'caching connection fields' do
+  class StubLogger < Logger
+    def initialize
+      @strio = StringIO.new
+      super(@strio)
+    end
+
+    def messages
+      @strio.string
+    end
+  end
+
   let(:query) do
     %Q{
       {
@@ -21,10 +32,34 @@ def execute(query, context = {})
     }
   end
 
+  let(:sql_logger) do
+    StubLogger.new.tap do |logger|
+      logger.formatter = proc do |_severity, _datetime, _progname, msg|
+        raw_sql = msg.match(/\(.*\)\s(?<sql>.*)/)["sql"]
+
+        "#{raw_sql}\n"
+      end
+    end
+  end
+
+  before { DB.logger = sql_logger }
+
   it 'produces the same result on miss or hit' do
     cold_results = execute(query)
     warm_results = execute(query)
 
     expect(cold_results).to eq warm_results
   end
+
+  it 'calls sql engine only one time per cached field' do
+    5.times { execute(query) }
+
+    expect(sql_logger.messages).to eq(
+      <<~SQL
+        SELECT * FROM `customers` ORDER BY `id` DESC LIMIT 1
+        SELECT * FROM `customers` WHERE `id` = '1'
+        SELECT * FROM `orders` WHERE (`orders`.`customer_id` = 1)
+      SQL
+    )
+  end
 end

spec/spec_helper.rb

@@ -29,6 +29,10 @@
     DB.logger = GraphQL::Cache.logger
   end
 
+  config.before(:each) do
+    GraphQL::Cache.cache.clear
+  end
+
   # required after GraphQL::Cache initialization because dev
   # schema uses cache and logger objects from it.
   require_relative '../test_schema'