[AWS] Tests covering "bin" interface

The `AWS` class has a number of lookups that need moving to the
`Fog::AWS` namespace to ease extraction. This adds tests for AWS current
interface.

spec/fog/bin/aws_spec.rb

@@ -7,4 +7,93 @@ describe AWS do
   include Fog::BinSpec
 
   let(:subject) { AWS }
+
+  KEY_CLASS_MAPPING = {
+    :auto_scaling => Fog::AWS::AutoScaling,
+    :beanstalk => Fog::AWS::ElasticBeanstalk,
+    :cdn => Fog::CDN::AWS,
+    :cloud_formation => Fog::AWS::CloudFormation,
+    :cloud_watch => Fog::AWS::CloudWatch,
+    :compute => Fog::Compute::AWS,
+    :data_pipeline => Fog::AWS::DataPipeline,
+    :ddb => Fog::AWS::DynamoDB,
+    :dynamodb => Fog::AWS::DynamoDB,
+    :dns => Fog::DNS::AWS,
+    :elasticache => Fog::AWS::Elasticache,
+    :elb => Fog::AWS::ELB,
+    :emr => Fog::AWS::EMR,
+    :glacier => Fog::AWS::Glacier,
+    :iam => Fog::AWS::IAM,
+    :redshift => Fog::AWS::Redshift,
+    :sdb => Fog::AWS::SimpleDB,
+    :simpledb => Fog::AWS::SimpleDB,
+    :ses => Fog::AWS::SES,
+    :sqs => Fog::AWS::SQS,
+    :eu_storage => Fog::Storage::AWS,
+    :storage => Fog::Storage::AWS,
+    :rds => Fog::AWS::RDS,
+    :sns => Fog::AWS::SNS,
+    :sts => Fog::AWS::STS
+  }
+
+  describe "#services" do
+    it "includes all services" do
+      assert_includes AWS.services, :auto_scaling
+      assert_includes AWS.services, :beanstalk
+      assert_includes AWS.services, :cdn
+      assert_includes AWS.services, :cloud_formation
+      assert_includes AWS.services, :cloud_watch
+      assert_includes AWS.services, :compute
+      assert_includes AWS.services, :data_pipeline
+      assert_includes AWS.services, :dynamodb
+      assert_includes AWS.services, :dns
+      assert_includes AWS.services, :elasticache
+      assert_includes AWS.services, :elb
+      assert_includes AWS.services, :emr
+      assert_includes AWS.services, :glacier
+      assert_includes AWS.services, :iam
+      assert_includes AWS.services, :redshift
+      assert_includes AWS.services, :rds
+      assert_includes AWS.services, :simpledb
+      assert_includes AWS.services, :ses
+      assert_includes AWS.services, :sqs
+      assert_includes AWS.services, :storage
+      assert_includes AWS.services, :sns
+      assert_includes AWS.services, :sts
+    end
+  end
+
+  describe "#class_for" do
+    describe "when key exists" do
+      it "maps to correct class" do
+        KEY_CLASS_MAPPING.each do |key, klass|
+          assert_equal klass, AWS.class_for(key)
+        end
+      end
+    end
+
+    describe "when key does not exist" do
+      it "raises ArgumentError" do
+        assert_raises(ArgumentError) { AWS.class_for(:bad_key) }
+      end
+    end
+  end
+
+  describe "#[]" do
+    describe "when service is recognised" do
+      it "returns correct instance" do
+        KEY_CLASS_MAPPING.each do |key, klass|
+          klass.stub(:new, true) do
+            assert klass, AWS[key]
+          end
+        end
+      end
+    end
+
+    describe "when service is not recognised" do
+      it "raises ArgumentError" do
+        assert_raises(ArgumentError) { AWS[:bad_service] }
+      end
+    end
+  end
 end