Add test for #63.

Author: Geoffroy Empain

.editorconfig

@@ -0,0 +1,9 @@
+# Editor configuration, see http://editorconfig.org
+root = true
+
+[*]
+charset = utf-8
+indent_style = space
+indent_size = 4
+insert_final_newline = true
+trim_trailing_whitespace = true

test/functional/prototype-problem.ts

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+import "reflect-metadata";
+import {defaultMetadataStorage} from "../../src/storage";
+import {Transform} from "../../src/decorators";
+import {classToPlain} from "../../src/index";
+import moment = require("moment");
+import Moment = moment.Moment;
+
+describe("basic functionality", () => {
+
+    it("should not throw error", () => {
+        defaultMetadataStorage.clear();
+
+        class User {
+            // As in https://github.com/gempain/class-transformer#additional-data-transformation
+            @Transform(value => moment(value), {toClassOnly: true})
+            created: Moment;
+        }
+
+        const user = new User();
+        user.created = moment();
+
+        const o = classToPlain(user);
+
+        o.should.not.be.undefined;
+
+    });
+
+});