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c++ TDD quest

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c++ TDD quest

Posted: Tue Jul 31, 2012 12:16 pm
by bbguimaraes
Hi. After a short programming-absence on the last semester (academic purposes), I started working on a company which applies TDD on its development process (ironically, the same university). They use the python language, so I decided to look for an alternative for c++, to use on my own projects. So I thought: "Hey, I could post my research on the forum, so people can use and learn from it too.". Then I thought there probably was already some posts about it. But I was wrong. If you're curious, search for "unit test": you'll find two unanswered posts. But I decided to do it anyway.

I'm not going to explain what TDD is and how it works. First, there's google. And I think the basic idea can be learned from the examples. I'm going to do my research and post it here, from time to time, so you can check it out, maybe learn something new and maybe help me with something or add new material. I'll leave this introduction on a post of its own.

Index:

Part I: Finding alternatives

Posted: Tue Jul 31, 2012 12:19 pm
by bbguimaraes
Here are the options I found after a short google search:
  • CppUnit: c++ port of JUnit, one of the first testing frameworks. This will probably be the last one tested, because I have preconcieved (bad) ideas about anything slightly related to Java.
  • boost::test: part of the famous boost library. If it's as good as the other boost libraries, I already have a favorite.
  • QtTest: part of the famouse Qt framework. If it's as good as the other Qt libraries, I already have a second favorite.
  • googletest: this one surprised me. Google has its own c++ test framework!
This is not a definitive list, I'll add items if I find others. I'm also looking for suggestions.

Re: c++ TDD quest

Posted: Tue Jul 31, 2012 5:04 pm
by dandymcgee
bbguimaraes wrote:I'm not going to explain what TDD is and how it works.
That's fine, but you could have at least said what the acronym stands for..
http://en.wikipedia.org/wiki/Test-driven_development

Part II: Hello world

Posted: Wed Aug 01, 2012 9:17 am
by bbguimaraes
Following the short introduction, here is the basic setup. I've covered installation on my Ubuntu test machine. I'm using apt to install the packages, so much of the complexity of setting up paths is hidden. For all the libraries though, installation basically meant putting headers and libraries on /usr/include and /usr/lib.

If you're wondering where is the CppUnit section: I'm sorry. I just couldn't find a simple program to run the tests. They all require a huge amount of code to setup the simplest of tests. I have a working example, that I'll post on the next sections.

Update Aug 09, 2012: I decided to include cxxtest too. I really liked the idea of parsing the headers to create the test runners. Let's see how it scales to more complex tests.

I've also decided to give CppUnit another chance. No, I'm kidding. I just looked at the code for the "minimal problem" and thought there were only two possibilities: (a) I clearly missed something, so someone can correct me (b) the code is so ridiculously long they deserve to be mocked.

This sections show:
  • installation of the library and compilation of a simple program
  • a simple program and its output
Index:

Part II: Hello world

Posted: Wed Aug 01, 2012 9:20 am
by bbguimaraes
boost::test

Install libraries

Code: Select all

sudo apt-get install libboost-test-dev
Compilation

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g++ main.cpp -o boost-test
Minimal program

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#define BOOST_TEST_MAIN
#include <boost/test/included/unit_test.hpp>
BOOST_AUTO_TEST_CASE(test) {}
Output

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Running 1 test case...
*** No errors detected

Part II: Hello world

Posted: Wed Aug 01, 2012 9:23 am
by bbguimaraes
QtTest

Install libraries

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sudo apt-get install libqt4-test
Compilation

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qmake -project "CONFIG += qtestlib"
qmake
make
Minimal program

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#include <QtTest/QtTest>
class Test : public QObject {};
QTEST_MAIN(Test)
#include <main.moc>
Output

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********* Start testing of QObject *********
Config: Using QTest library 4.8.1, Qt 4.8.1
PASS   : QObject::initTestCase()
PASS   : QObject::cleanupTestCase()
Totals: 2 passed, 0 failed, 0 skipped
********* Finished testing of QObject *********

Part II: Hello world

Posted: Wed Aug 01, 2012 9:24 am
by bbguimaraes
googletest

Installation

Code: Select all

sudo apt-get install libgtest-dev
cd /usr/src/gtest
sudo cmake CMakeLists.txt
sudo make
cd /usr/lib
sudo ln -s /usr/src/gtest/libgtest.a libgtest.a
sudo ln -s /usr/src/gtest/libgtest_main.a libgtest_main.a
Compilation

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g++ main.cpp -lgtest_main -lgtest -pthread -o googletest
Minimal program

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#include <gtest/gtest.h>
TEST(TestCase, Test) {}
Output

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Running main() from gtest_main.cc
[==========] Running 1 test from 1 test case.
[----------] Global test environment set-up.
[----------] 1 test from TestCase
[ RUN      ] TestCase.Test
[       OK ] TestCase.Test (0 ms)
[----------] 1 test from TestCase (0 ms total)
[----------] Global test environment tear-down
[==========] 1 test from 1 test case ran. (0 ms total)
[  PASSED  ] 1 test.

Part II: Hello World

Posted: Thu Aug 09, 2012 2:30 pm
by bbguimaraes
cxxtest

Installation

Code: Select all

add-apt-repository ppa:dhart/ppa
sudo apt-get install cxxtest
Compilation

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cxxtestgen --error-printer -o main.cpp Test.h
g++ main.cpp -o cxxtest
Minimal program

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include <cxxtest/TestSuite.h>
using CxxTest::TestSuite;

class Test : public CxxTest::TestSuite {
   public:
       void testCxxtest() {}
};
Output

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Running 1 test.OK!

Part II: Hello World

Posted: Thu Aug 09, 2012 2:39 pm
by bbguimaraes
CppUnit

Installation

Code: Select all

sudo apt-get install libcppunit-dev
Compilation

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g++ main.cpp -lcppunit -o cppunit
Minimal program

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#include <cppunit/extensions/HelperMacros.h>
#include <cppunit/TestFixture.h>
using CPPUNIT_NS::TestFixture;

#include <cppunit/ui/text/TestRunner.h>
using CPPUNIT_NS::TextTestRunner;

#include <cppunit/extensions/TestFactoryRegistry.h>
using CPPUNIT_NS::TestFactoryRegistry;

class Test : public TestFixture {
    virtual void runTest() {}
};

int main() {
    TextTestRunner runner;
    TestFactoryRegistry & registry = TestFactoryRegistry::getRegistry();
    runner.addTest(registry.makeTest());
    runner.run();
    return 0;
}
Output (no whitespaces added)

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OK (0 tests)

Re: c++ TDD quest

Posted: Thu Aug 09, 2012 2:46 pm
by Falco Girgis
So what are you liking about boost::test better than QT's testing framework? I have been a long-time QT loyalist, and you have gotten me curious. I have never done much looking into a testing framework.

Re: c++ TDD quest

Posted: Thu Aug 09, 2012 3:11 pm
by bbguimaraes
Actually, I'm still in a very early stage of comparison. What I meant is that, if boost::test and QtTest were in an equal level, I'd choose boost, for the single fact that it's more modularized than Qt (smaller footprint if you want to get fancy). That's inherent to the purpose of both of them. If the project already has Qt dependencies, I think I'd choose Qt. It probably has easier ways do test GUIs (at least its own). So far (I haven't tested cxxtest properly, which seems pretty promising), they seem like the two best alternatives.

Yes, I'm biased. Sue me.

Part III: First tests

Posted: Mon Oct 15, 2012 12:31 am
by bbguimaraes
Now we're going to de some simple tests, just to learn how each library structures each test and combines all of them on execution, including the output of running for many tests. The function used on the tests is the following:

Code: Select all

int sum(int n1, int n2) {
    return 3;
}
That is not much useful for everyday use, but it will serve in our tests to show success and failure messages.

Index:

Part III: First tests

Posted: Mon Oct 15, 2012 12:32 am
by bbguimaraes
boost::test

Code

Code: Select all

#define BOOST_TEST_MODULE Test
#include <boost/test/unit_test.hpp>

int sum(int n1, int n2) {
    return 3;
}

BOOST_AUTO_TEST_CASE(test1plus2) {
    BOOST_CHECK_EQUAL(sum(1, 2), 3);
}

BOOST_AUTO_TEST_CASE(test2plus2) {
    BOOST_CHECK_EQUAL(sum(2, 2), 4);
}
Output

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Running 2 test cases...
main.cpp(13): error in "test2plus2": check sum(2, 2) == 4 failed [3 != 4]

*** 1 failure detected in test suite "Test"
Note
Since we're moving out of compiling the test runner with our executable to only linking to the pre-compiled library, we need to alter our compilation command to:

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g++ main.cpp -lboost_test_exec_monitor -o boost-test

Part III: First tests

Posted: Mon Oct 15, 2012 12:41 am
by bbguimaraes
QtTest

Code

Code: Select all

int sum(int n1, int n2) {
    return 3;
}

class Test : public QObject {
    Q_OBJECT

    private slots:
        void test1plus2() {
            QCOMPARE(sum(1, 2), 3);
        }

        void test2plus2() {
            QCOMPARE(sum(2, 2), 4);
        }
};

QTEST_MAIN(Test)
#include <main.moc>
Output

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********* Start testing of Test *********
Config: Using QTest library 4.8.1, Qt 4.8.1
PASS   : Test::initTestCase()
PASS   : Test::test1plus2()
FAIL!  : Test::test2plus2() Compared values are not the same
   Actual (sum(2, 2)): 3
   Expected (4): 4
   Loc: [main.cpp(16)]
PASS   : Test::cleanupTestCase()
Totals: 3 passed, 1 failed, 0 skipped
********* Finished testing of Test *********
Note
I'm just going to get out of the way here to say that it took me two minutes to learn how to write this program. Once again, Qt proved to have an excelent documentation. You can also see how complete the output is, showing the expressions and values of both parameters of QCOMPARE, and the line on the file where it's being called.

Part III: First tests

Posted: Mon Oct 15, 2012 12:51 am
by bbguimaraes
googletest

Code

Code: Select all

#include <gtest/gtest.h>

int sum(int n1, int n2) {
    return 3;
}

TEST(test1plus2, Test) {
    ASSERT_EQ(3, sum(1, 2));
}

TEST(test2plus2, Test) {
    ASSERT_EQ(4, sum(1, 2));
}
Output

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Running main() from gtest_main.cc
[==========] Running 2 tests from 2 test cases.
[----------] Global test environment set-up.
[----------] 1 test from test1plus2
[ RUN      ] test1plus2.Test
[       OK ] test1plus2.Test (0 ms)
[----------] 1 test from test1plus2 (0 ms total)

[----------] 1 test from test2plus2
[ RUN      ] test2plus2.Test
main.cpp:12: Failure
Value of: sum(1, 2)
  Actual: 3
Expected: 4
[  FAILED  ] test2plus2.Test (0 ms)
[----------] 1 test from test2plus2 (0 ms total)

[----------] Global test environment tear-down
[==========] 2 tests from 2 test cases ran. (1 ms total)
[  PASSED  ] 1 test.
[  FAILED  ] 1 test, listed below:
[  FAILED  ] test2plus2.Test

 1 FAILED TEST
(Yet another) Note
I'm attaching a screenshot, because you can't see here that the output is colored.
All times are UTC-06:00
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