谷歌測試undefined參考使用SetUpTestCase靜態變量

Question

我正在寫一個測試用例，將有一個SetUpTestCase()方法，將分配共享資源雖然我收到未定義的參考鏈接器錯誤。

class ParsingEventsTest: public ::testing::Test { 
    protected: 

     static xml eventXml; 

     static void SetUpTestCase() { 
      ManagedObjectManagerSingleton::GET_SINGLETON().initializeTestEnvironment(PATH_TO_FILE); 
      eventXml= *ManagerSingleton::GET_SINGLETON().parse(PATH_TO_INPUT_FILES); 
     } 

     virtual void SetUp() {} 
     virtual void TearDown() {} 
}; 

這將導致：

../test/ParsingEventsTest.o: In function `ParsingEventsTest::SetUpTestCase()': 
ParsingEventsTest.cpp:(.text._ZN17ParsingEventsTest13SetUpTestCaseEv[ParsingEventsTest::SetUpTestCase()]+0xa1): undefined reference to `ParsingEventsTest::eventXml' 
ParsingEventsTest.cpp:(.text._ZN17ParsingEventsTest13SetUpTestCaseEv[ParsingEventsTest::SetUpTestCase()]+0xb0): undefined reference to `ParsingEventsTest::eventXml' 
ParsingEventsTest.cpp:(.text._ZN17ParsingEventsTest13SetUpTestCaseEv[ParsingEventsTest::SetUpTestCase()]+0xbd): undefined reference to `ParsingEventsTest::eventXml' 
ParsingEventsTest.cpp:(.text._ZN17ParsingEventsTest13SetUpTestCaseEv[ParsingEventsTest::SetUpTestCase()]+0xc2): undefined reference to `ParsingEventsTest::eventXml' 
ParsingEventsTest.cpp:(.text._ZN17ParsingEventsTest13SetUpTestCaseEv[ParsingEventsTest::SetUpTestCase()]+0xce): undefined reference to `ParsingEventsTest::eventXml' 
../test/ParsingEventsTest.o:ParsingEventsTest.cpp:(.text._ZN17ParsingEventsTest13SetUpTestCaseEv[ParsingEventsTest::SetUpTestCase()]+0xdd): more undefined references to `ParsingEventsTest::eventXml' follow 
collect2: ld returned 1 exit status 

---

編輯：

這也適用於非常簡單的例如int allocation

class ParsingEventsTest: public ::testing::Test { 
    protected: 

     static int *x; 

     static void SetUpTestCase() { 
      x = new int [30]; 
     } 

     static void TearDownTestCase() { 
      delete [] x; 
     } 

     virtual void SetUp() {} 
     virtual void TearDown() {} 
}; 

Answer 1

您只聲明字段eventXml。你需要在某個地方定義它。在某些cpp文件你必須把線像

xml ParsingEventsTest::eventXml; 

編輯
至於爲什麼需要它的理由：靜態成員的聲明中類不能定義它。如果是這樣，每個包含類定義的翻譯單元都會定義它。但是每個程序只需要一個定義，所以你必須選擇在類定義之外定義成員的位置（通常在一些.cpp文件中，最好是具有成員函數定義的成員）。語法如上所示。