Unit testing with Qt test

Unit testing with Qt Test How to test C++ and GUI code with Qt

In this presentation ● Introduction to Qt Test ○ Setting up a project ○ Unit test class ○ Testing values and conditions ○ Useful macros ● Data driven testing ● GUI testing ○ Testing a QWidget ○ Sending input events to a widget ○ Testing keyboard focus ○ Testing signals ● Qt Creator integration ● Q&A 2

Let me introduce myself Professional life ● MSc Computer Science (Naples, IT) ● Game development (London, UK) ● R&D (Barcelona, ES) ● C++/Qt consultant (Barcelona, ES) After work 3 ● Tech blogging ● Dev projects ● Blender 3D ● Skydiving

Unit test class #include <QtTest> class TestMinimal : public QObject // test case { Q_OBJECT private slots: void testFoo(); // test 1 void testBar(); // test 2 }; 5

Unit test class - special members class TestFull : public QObject { Q_OBJECT private slots: void initTestCase(); void init(); void cleanup(); void cleanupTestCase(); }; // example execution flow TestFull(); initTestCase(); init(); test1(); cleanup(); init(); test2(); cleanup(); cleanupTestCase(); ~TestFull(); 6

Generating main class TestMinimal : public QObject { ... }; // QApplication - full Qt environment QTEST_MAIN(TestMinimal) // QCoreApplication - no GUI, but event loop is available QTEST_GUILESS_MAIN(TestMinimal) // no Qt application, C++ testing only QTEST_APPLESS_MAIN(TestMinimal) #include "TestMinimal.moc" 7

Setting up a project (in Qt Creator) ● Subdirs project ○ Auto Test Project (basic) ○ Qt Unit Test (advanced) 8

Testing values and conditions void TestCalculator::testConstructor() { // -- default constructor -- Calculator c1; QVERIFY(c1.isValid()); // -- full constructor -- const int A = 10; const int B = 2; Calculator c2(A, B); QVERIFY2(c2.getA() == A, "first operand doesn't match"); QVERIFY2(c2.getB() == B, "second operand doesn't match"); } 9

Testing values and conditions - failures QVERIFY(c1.isValid()); FAIL! : TestCalculator::testConstructor() 'c1.isValid()' returned FALSE. () Loc: [../../UnitTests/TestCalculator/TestCalculator.cpp(30)] QVERIFY2(c2.getA() == A, "first operand doesn't match"); FAIL! : TestCalculator::testConstructor() 'c2.GetA() == A' returned FALSE. (first operand doesn't match) Loc: [../../UnitTests/TestCalculator/TestCalculator.cpp(35)] 10

Comparing values void TestCalculator::testSum() { // sum default QCOMPARE(mCalc.Sum(), A0 + B0); } FAIL! : TestCalculator::testSum() Compared values are not the same Actual (mCalc.Sum()): 1 Expected (A0 + B0) : 0 Loc: [../../UnitTests/TestCalculator/TestCalculator.cpp(58)] 11

Useful macros // fail current test QFAIL("Fail message..."); // allow to fail next check QEXPECT_FAIL("DataRowN", "Expected fail message", Continue); QCOMPARE(a, b); // skip current test QSKIP("Skip message..."); // print warning message in logs QWARN("Warning message"); 12

More useful macros // Test and compare values with timeout QTRY_VERIFY_WITH_TIMEOUT(condition, timeout) QTRY_VERIFY2_WITH_TIMEOUT(condition, message, timeout) QTRY_COMPARE_WITH_TIMEOUT(actual, expected, timeout) // QVERIFY for intercepting exceptions QVERIFY_EXCEPTION_THROWN(expression, exceptionType) 13

What, why and when The concept ● Separate test and data ● Similar to using a database Advantages ● Avoid repetition and multiple initializations ● Very useful to validate different input/data Not useful when ● Tests are not focused on data ● Tests are pretty simple 15

Defining the data void TestCalculator::testDiff_data() { QTest::addColumn<int>("a"); // col 0 QTest::addColumn<int>("b"); // col 1 QTest::addColumn<int>("res"); // col 2 QTest::newRow("all 0") << 0 << 0 << 0; // row 0 QTest::newRow("same number") << 10 << 10 << 0; // row 1 } INDEX NAME a b result 0 “all 0” 0 0 0 1 “same number” 10 10 0 16

Writing the test function void TestCalculator::testDiff() { // retrieve data QFETCH(int, a); QFETCH(int, b); QFETCH(int, result); // use data mCalc.SetValues(a, b); // check results QCOMPARE(mCalc.Diff(), result); } 17

Testing a GUI Ideally use modular configuration ● Container project ○ Application ○ Widgets library (dynamic/shared) ○ Unit tests Usually deeper access is required ● Provide extra public functions ● Testcase class is friend ● Visitor class is friend and used by multiple testcases ● Children navigation 19

Example GUI ● QWidget ○ 2x QLineEdit (input) ○ 2x QPushButton (action) ○ 1x QLabel (output) input action output 20

Sending input events to a QWidget void TestCalculator::TestClear() { // write to input fields QTest::keyClicks(mPanel.mInputA, “hello ”); QTest::keyClicks(mPanel.mInputB, “world”); // click button CONCAT QTest::mouseClick(mPanel.mButtonConcat, Qt::LeftButton); // click button CLEAR QTest::mouseClick(mPanel.mButtonCancel, Qt::LeftButton); // check all fields are empty QVERIFY2(mPanel.mInputA->text().isEmpty(), "Input A not empty"); QVERIFY2(mPanel.mInputB->text().isEmpty(), "Input B not empty"); QVERIFY2(mPanel.mLabelRes->text().isEmpty(), "Result not empty"); } 21

Testing keyboard focus 1/2 void TestCalculator::TestFocusUsage() { // IMPORTANT - enables focus and widget events QApplication::setActiveWindow(&mPanel); // set initial focus to input A mPanel.mInputA->setFocus(); QVERIFY2(mPanel.mInputA->hasFocus(), "Input A doesn't have focus"); // write input A QTest::keyClicks(QApplication::focusWidget(), “hello ”); // move focus to input B QTest::keyClick(&mPanel, Qt::Key_Tab); QVERIFY2(mPanel.mInputB->hasFocus(), "Input B doesn't have focus"); // write input B QTest::keyClicks(QApplication::focusWidget(), ”world”); 22

Testing keyboard focus 2/2 // move focus to button CONCAT QTest::keyClick(&mPanel, Qt::Key_Tab); QVERIFY2(mPanel.mButtonConcat->hasFocus(), "Button CONCAT doesn't have focus"); // press button CONCAT QTest::keyClick(QApplication::focusWidget(), Qt::Key_Space); QCOMPARE(mPanel.mLabelRes->text(), ”hello world”); // move focus to button CANCEL QTest::keyClick(&mPanel, Qt::Key_Tab); QVERIFY2(mPanel.mButtonCancel->hasFocus(), "Button CANCEL doesn't have focus"); // press button CANCEL QTest::keyClick(QApplication::focusWidget(), Qt::Key_Space); QVERIFY2(mPanel.mInputA->text().isEmpty(), "Cancel didn't work on input A"); QVERIFY2(mPanel.mInputB->text().isEmpty(), "Cancel didn't work on input B"); QVERIFY2(mPanel.mLabelRes->text().isEmpty(), "Cancel didn't work on res label"); } 23

Testing signals 1/2 void TestPanelConcat::TestSignals() { // set input mPanel.mInputA->setText(“hello ”); mPanel.mInputB->setText(“world”); // create spy objects - QList on steroids QSignalSpy spy1(&mPanel, &PanelConcat::DataAvailable); QSignalSpy spy2(&mPanel, &PanelConcat::DataCleared); // click button CONCAT and check signals received QTest::mouseClick(mPanel.mButtonConcat, Qt::LeftButton); QCOMPARE(spy1.count(), 1); QCOMPARE(spy2.count(), 0); void PanelConcat::ConcatData() { emit DataAvailable(mLabelRes->text()); } void PanelConcat::CancelData() { emit DataCleared(); } 24

Testing signals 2/2 // check parameter of the signal QList<QVariant> args = spy1.takeFirst(); QCOMPARE(args.at(0).toString(), ”hello world”); // click button CANCEL QTest::mouseClick(mPanel.mButtonCancel, Qt::LeftButton); QCOMPARE(spy1.count(), 0); QCOMPARE(spy2.count(), 1); // check parameter of the signal args = spy2.takeFirst(); QVERIFY2(args.empty(), "DataCleared signal has parameters now?!?"); } 25

Qt Creator integration Tests panel Test Results panel ● Enable/disable tests ● Run one or more tests ● Fine level of detail ● See results clearly ● Jump to tests with 1 click ● Filter messages 27

Questions & Answers (& References) Extended articles: http://blog.davidecoppola.com/category/qt/ Example code: https://github.com/vivaladav/BitsOfBytes QTest namespace: https://doc.qt.io/qt-5/qtest.html @vivaladav_3d @vivaladav_it @vivaladavin/davidecoppola/ 29

Unit testing with Qt test

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