diff --git a/EVReflection/EVReflectionTests/EVReflectionTests.swift b/EVReflection/EVReflectionTests/EVReflectionTests.swift
index 5c863668..004555dc 100644
--- a/EVReflection/EVReflectionTests/EVReflectionTests.swift
+++ b/EVReflection/EVReflectionTests/EVReflectionTests.swift
@@ -82,6 +82,8 @@ class EVReflectionTests: XCTestCase {
         let x = TestObject2c(dictionary: ["objectValue": "tst", "default":"default"])
         XCTAssertEqual(x.objectValue, "tst", "objectValue should have been set")
         XCTAssertEqual(x._default, "default", "default should have been set")
+        let json = x.toJsonString(true)
+        XCTAssertTrue(!json.containsString("_default"), "Key should have been cleaned up")
         
         let y = EVReflection.fromDictionary(["a":"b"], anyobjectTypeString: "NotExistingClassName")
         XCTAssertNil(y, "Class is unknow, so we should not have an instance")