Support using Aws::Google.config without any shared AWS config

Author: wjordan

lib/aws/google/credential_provider.rb

@@ -22,14 +22,17 @@ def google_credentials(options)
 
     module GoogleSharedCredentials
       def google_credentials_from_config(opts = {})
-        p = opts[:profile] || @profile_name
+        google_opts = {}
         if @config_enabled && @parsed_config
-          google_opts = @parsed_config.
+          p = opts[:profile] || @profile_name
+          google_opts.merge!(@parsed_config.
             fetch(p, {}).fetch('google', {}).
             transform_keys(&:to_sym)
-          if google_opts.merge(::Aws::Google.config).has_key?(:role_arn)
-            Google.new(google_opts)
-          end
+          )
+        end
+        google_opts.merge!(::Aws::Google.config)
+        if google_opts.has_key?(:role_arn)
+          Google.new(google_opts)
         end
       end
     end

test/aws/google_test.rb

@@ -204,5 +204,27 @@
         Aws::Google.new(config).credentials
       end
     end
+    
+    describe 'no shared config' do
+      before do
+        Aws.shared_config.fresh(
+          config_enabled: true,
+          credentials_path: nil,
+          config_path: nil
+        )
+      end
+
+      it 'creates client credentials from Google config' do
+        Aws::Google.stubs(:config).returns(config)
+
+        @oauth_default.once
+        system.times(5)
+
+        c = Aws::STS::Client.new(region: 'us-east-1').config.credentials
+        _(c.credentials.access_key_id).must_equal credentials[:access_key_id]
+        _(c.credentials.secret_access_key).must_equal credentials[:secret_access_key]
+        _(c.credentials.session_token).must_equal credentials[:session_token]
+      end
+    end
   end
 end