Add test for load_env_plugins

Author: djmarcin

bundler/spec/bundler/plugin/installer_spec.rb

@@ -109,6 +109,12 @@
           expect(result["re-plugin"].full_gem_path).
             to eq(global_plugin_gem("re-plugin-1.0").to_s)
         end
+
+        it "loads env plugins" do
+          expect(Bundler).to receive_message_chain("rubygems.load_env_plugins")
+          expect(result["re-plugin"].full_gem_path).
+            to eq(global_plugin_gem("re-plugin-1.0").to_s)
+        end
       end
 
       context "multiple plugins" do