Go開發筆記 - 使用 net/http 處理 URL Redirect 和 Cookie 之 Service Unit Test 需求

最近用 Golang 撰寫 Service Unit Test 時，練了一下 net/http 要如何處理 HTTP Response Header Location 的處理。主要是在使用 net/http 的 http.Client 時，可以加設定 CheckRedirect 的機制來阻擋 URL Redirect 的行為，藉以檢驗 URL Redirect 是否正確。

//httpClient := http.DefaultClient

httpClient := &http.Client{}

httpClient.CheckRedirect = func(req *http.Request, via []*http.Request) error {

return http.ErrUseLastResponse

}

if jar, err := cookiejar.New(nil); err == nil {

httpClient.Jar = jar

}

如此，做 Service Unit Test 時，在發送 HTTP GET request or HTTP HEAD request 時，可以停下來，看看要跳轉到哪裡，以此判斷跳轉機制是否正常。

接著，碰到了另一個問題: 在 follow URL Redirect 後，似乎跳轉過程中產生的 Cookie 都沒有被記錄下來？例如最後的 response.Cookies() 輸出，的確只列出最後的 Response Cookies 資料。這時想要驗證中間的 Cookie 資訊，則需要瀏覽 httpClient.Jar 資料：

for _, c := range(httpClient.Jar.Cookies(res.Request.URL)) {

fmt.Println(c)

}

如此就可以搞定 URL Redirect 驗證，以及全部過程的產生的 Cookie 檢查！當然，若要更細膩地去追蹤每次 URL Redirect 時，產生的 Response Cookies 資料，可以透過 httpClient.CheckRedirect 那處理：

httpClient.CheckRedirect = func(req *http.Request, via []*http.Request) error {

for _, c := range (req.Response.Cookies()) {

fmt.Println(c)

}

}

參考資料：

• https://pkg.go.dev/net/http#Client
• https://cs.opensource.google/go/go/+/refs/tags/go1.18.3:src/net/http/client.go
• https://cs.opensource.google/go/go/+/refs/tags/go1.18.3:src/net/http/client.go;l=493
• https://cs.opensource.google/go/go/+/refs/tags/go1.18.3:src/net/http/client.go;l=811
• https://pkg.go.dev/net/http/cookiejar#Jar.Cookies
• https://cs.opensource.google/go/go/+/refs/tags/go1.18.3:src/net/http/cookiejar/jar.go

[CPP] Incremental Test Case for C++ Usage via Google Test @ Ubuntu 14.04

既然做了 Unit Test 了，就希望 Test Case 可以不斷地累積下來。昨晚跟總監級的高手閒聊工作瑣事，以 Python 跟 MongoDB 的互動為例，其實 PyMono 很多操作都還是撰寫 Javascript ，只是從 Python 發動罷了，這時候最佳的設計是讓 Javascript 獨立出來，如此一來可以切割工作出來，讓把玩 Javascript 就專心把玩，而不要每次要改 Javascript 時，還得去動 Python code。

這樣的情境跟 Test Case 有點類似，有沒有辦法讓 Test case 增加時，不必動到測試的邏輯程式？解法就是把 Test Case 用目錄管理，每次做 Unit Test 時，是去掃目錄的檔案出來即可。

片段程式碼：

#include <dirent.h>
bool getFiles(std::string dir, std::vector<std::string> &files) {
        DIR *dp;
        struct dirent *dirp;
        if((dp  = opendir(dir.c_str())) == NULL)
                return false;
        while ((dirp = readdir(dp)) != NULL)
                if(dirp->d_name && dirp->d_name[0] != '.')
                        files.push_back(dir+"/"+std::string(dirp->d_name));
        closedir(dp);
        return true;
}

const std::string testcase_dir_Func1 = "testcase_dir";
TEST(MyJob, testFunc1) {
        std::vector<std::string> testcase;
        std::string dirTarget = testcase_dir_Func1;
        ASSERT_EQ(getFiles(dirTarget,testcase), true);
        ASSERT_EQ(testcase.size() > 0, true);
        for(int i=0 ; i<testcase.size() ; ++i) {
                std::fstream input(testcase[i], std::fstream::binary|std::fstream::in);
                std::stringstream buffer;
                buffer << input.rdbuf();
                ASSERT_EQ(buffer.str().length() > 10, true);

// ...
        }
}

[CPP] Unit Test for C++ Usage via Google Test @ Ubuntu 14.04

跟友人閒聊把玩 CPP 的心得，就被推坑到 Google test 啦：Google C++ Testing Framework

看一下簡介就...準備跳槽了 XD

Who Is Using Google Test?

In addition to many internal projects at Google, Google Test is also used by the following notable projects:

• The Chromium projects (behind the Chrome browser and Chrome OS)
• The LLVM compiler
• Protocol Buffers (Google's data interchange format)

安裝：

$ sudo apt-get install cmake libgtest-dev
$ mkdir gtest && cd gtest
$ cmake /usr/src/gtest/
-- The CXX compiler identification is GNU 4.8.2
-- The C compiler identification is GNU 4.8.2
-- Check for working CXX compiler: /usr/bin/c++
-- Check for working CXX compiler: /usr/bin/c++ -- works
-- Detecting CXX compiler ABI info
-- Detecting CXX compiler ABI info - done
-- Check for working C compiler: /usr/bin/cc
-- Check for working C compiler: /usr/bin/cc -- works
-- Detecting C compiler ABI info
-- Detecting C compiler ABI info - done
-- Found PythonInterp: /usr/bin/python (found version "2.7.6")
-- Looking for include file pthread.h
-- Looking for include file pthread.h - found
-- Looking for pthread_create
-- Looking for pthread_create - not found
-- Looking for pthread_create in pthreads
-- Looking for pthread_create in pthreads - not found
-- Looking for pthread_create in pthread
-- Looking for pthread_create in pthread - found
-- Found Threads: TRUE
-- Configuring done
-- Generating done
-- Build files have been written to: /path/gtest

$ make
Scanning dependencies of target gtest
[ 50%] Building CXX object CMakeFiles/gtest.dir/src/gtest-all.cc.o
Linking CXX static library libgtest.a
[ 50%] Built target gtest
Scanning dependencies of target gtest_main
[100%] Building CXX object CMakeFiles/gtest_main.dir/src/gtest_main.cc.o
Linking CXX static library libgtest_main.a
[100%] Built target gtest_main

$ sudo cp *.a /usr/lib

試用：

$ vim gtest.cpp
#include <gtest/gtest.h>

int main(int argc, char** argv) {
        testing::InitGoogleTest(&argc, argv);
        return RUN_ALL_TESTS();
}
$ g++ gtest.cpp -lgtest -lpthread
$ ./a.out
[==========] Running 0 tests from 0 test cases.
[==========] 0 tests from 0 test cases ran. (0 ms total)
[  PASSED  ] 0 tests.

測試失敗範例：

$ vim gtest.cpp
#include <gtest/gtest.h>

TEST(MyJob, Action1) {
    ASSERT_EQ(0, 1);
}

int main(int argc, char** argv) {
        testing::InitGoogleTest(&argc, argv);
        return RUN_ALL_TESTS();
}

$ g++ gtest.cpp -lgtest -lpthread
$ ./a.out

[==========] Running 1 test from 1 test case.
[----------] Global test environment set-up.
[----------] 1 test from MyJob
[ RUN      ] MyJob.Action1
gtest.cpp:4: Failure
Value of: 1
Expected: 0
[  FAILED  ] MyJob.Action1 (1 ms)
[----------] 1 test from MyJob (1 ms total)

[----------] Global test environment tear-down
[==========] 1 test from 1 test case ran. (1 ms total)
[  PASSED  ] 0 tests.
[  FAILED  ] 1 test, listed below:
[  FAILED  ] MyJob.Action1

 1 FAILED TEST

測試成功的範例：

$ vim gtest.cpp
#include <gtest/gtest.h>

TEST(MyJob, Action1) {
    ASSERT_EQ(0, 0);
}

int main(int argc, char** argv) {
        testing::InitGoogleTest(&argc, argv);
        return RUN_ALL_TESTS();
}

$ g++ gtest.cpp -lgtest -lpthread
$ ./a.out

[==========] Running 1 test from 1 test case.
[----------] Global test environment set-up.
[----------] 1 test from MyJob
[ RUN      ] MyJob.Action1
[       OK ] MyJob.Action1 (0 ms)
[----------] 1 test from MyJob (0 ms total)

[----------] Global test environment tear-down
[==========] 1 test from 1 test case ran. (1 ms total)
[  PASSED  ] 1 test.

[CPP] Unit Test for C++ Usage via CppUnit @ Ubuntu 14.04

隨著時間越來越少後，不知不覺更在意"成果"是否能夠年年累積。想了一會兒後，最佳的方式就是引進軟工管理，除了最基本的版本控制外，幫自己把玩的小玩意 open source 及增加 reuse 的機會也很重要，維護方面則是從簡易人眼的測試改成更制式的 unit test 架構，最好能夠定時批次測試等。只不過採用制式的 unit test 不見得適合 startup 環境，畢竟時間寶貴，有些 prototype 生命週期很短。

在此以 CppUnit 為例，筆記一下怎樣快速使用，更多簡介請參考 CppUnit 文件。

安裝：

$ sudo apt-get install libcppunit-dev

$ vim t.cpp
#include <cppunit/ui/text/TestRunner.h>
#include <cppunit/extensions/HelperMacros.h>
#include <cppunit/TestResult.h>
#include <cppunit/CompilerOutputter.h>
#include <cppunit/TestResultCollector.h>
#include <cppunit/BriefTestProgressListener.h>

class SampleTest : public CppUnit::TestFixture {
private:
int a;
public:
void setUp() {
a = 0;
}
void tearDown() {
a = 0;
}
static CppUnit::Test *suite() {
CppUnit::TestSuite *suiteOfTests = new CppUnit::TestSuite( "SampleTest" );
suiteOfTests->addTest( new CppUnit::TestCaller<SampleTest>(
"testSample",
&SampleTest::testSample
));
return suiteOfTests;
}
void testSample() {
CPPUNIT_ASSERT( a == 10 );
}
};

int main() {
std::cout << "\n\n=== Style 1 ===\n\n";
{
CppUnit::TestCaller<SampleTest> test ( "testSample", &SampleTest::testSample );

CppUnit::BriefTestProgressListener progress;
CppUnit::TestResultCollector collectedresults;
CppUnit::TestResult result;
result.addListener(&progress);
test.run( &result );

CppUnit::CompilerOutputter outputter( &collectedresults, std::cerr );
}

std::cout << "\n\n=== Style 2 ===\n\n";
{
CppUnit::TestSuite suite;
suite.addTest( new CppUnit::TestCaller<SampleTest>(
"testSample",
&SampleTest::testSample
));

CppUnit::BriefTestProgressListener progress;
CppUnit::TestResultCollector collectedresults;
CppUnit::TestResult result;
result.addListener(&progress);
suite.run( &result );

CppUnit::CompilerOutputter outputter( &collectedresults, std::cerr );
}

std::cout << "\n\n=== Style 3 ===\n\n";
{
CppUnit::TextUi::TestRunner runner;
runner.addTest( SampleTest::suite() );
runner.run();
}
return 0;
}

測試成功：

=== Style 1 ===

testSample : OK


=== Style 2 ===

testSample : OK


=== Style 3 ===

.


OK (1 tests)

測試失敗：

=== Style 1 ===

testSample : assertion


=== Style 2 ===

testSample : assertion


=== Style 3 ===

.F


!!!FAILURES!!!
Test Results:
Run:  1   Failures: 1   Errors: 0


1) test: testSample (F) line: 27 t.cpp
assertion failed
- Expression: a == 10

目前大概打算對自定的 class 編寫一些偏邏輯層面的 unit test，例如 bool testFunc1(); 的方式，成功就回傳 true，但不套用任何 unit test framework，如此一來純邏輯的驗證更可以適用在不同平台，而要再加上特定的 unit test framework (如 CppUnit) 時，只需簡易套用，可以直接 reusable 而不必重頭寫。