如果出现警告，如何立即使自动测试失败

Question

我想在测试代码中打印警告时立即使任何自动测试失败，这样我就不会在输出中错过它并在以后出现奇怪的测试失败。

我想我可以为此使用qInstallMessageHandler()。我修改了here的例子：

#include <QtTest>

class AutoTest : public QObject
{
    Q_OBJECT

public:
    AutoTest();
    ~AutoTest();

private slots:
    void test_case1();

};

void warningMessageHandler(QtMsgType type, const QMessageLogContext &context, const QString &msg)
{
    QByteArray localMsg = msg.toLocal8Bit();
    const char *file = context.file ? context.file : "";
    const char *function = context.function ? context.function : "";
    switch (type) {
    case QtDebugMsg:
        fprintf(stderr, "Debug: %s (%s:%u, %s)\n", localMsg.constData(), file, context.line, function);
        break;
    case QtInfoMsg:
        fprintf(stderr, "Info: %s (%s:%u, %s)\n", localMsg.constData(), file, context.line, function);
        break;
    case QtWarningMsg:
        fprintf(stderr, "Warning: %s (%s:%u, %s)\n", localMsg.constData(), file, context.line, function);
        exit(1);
    case QtCriticalMsg:
        fprintf(stderr, "Critical: %s (%s:%u, %s)\n", localMsg.constData(), file, context.line, function);
        break;
    case QtFatalMsg:
        fprintf(stderr, "Fatal: %s (%s:%u, %s)\n", localMsg.constData(), file, context.line, function);
        break;
    }
}

AutoTest::AutoTest()
{
    qInstallMessageHandler(warningMessageHandler);
}

AutoTest::~AutoTest()
{

}

void AutoTest::test_case1()
{
    qWarning() << "This should cause the application to exit with code 1";
}

QTEST_APPLESS_MAIN(AutoTest)

#include "tst_autotest.moc"

但是，测试应用程序并没有按预期提前退出：

17:32:04: Starting /Users/mitch/dev/temp/autotest-qt5_14_fw-Debug/autotest.app/Contents/MacOS/autotest ...
********* Start testing of AutoTest *********
Config: Using QtTest library 5.14.0, Qt 5.14.0 (x86_64-little_endian-lp64 shared (dynamic) release build; by Clang 10.0.0 (clang-1000.11.45.2) (Apple))
PASS   : AutoTest::initTestCase()
QWARN  : AutoTest::test_case1() This should cause the application to exit
PASS   : AutoTest::test_case1()
PASS   : AutoTest::cleanupTestCase()
Totals: 3 passed, 0 failed, 0 skipped, 0 blacklisted, 2ms
********* Finished testing of AutoTest *********
17:32:04: /Users/mitch/dev/temp/autotest-qt5_14_fw-Debug/autotest.app/Contents/MacOS/autotest exited with code 0

我在消息处理函数中设置了一个断点，但它没有被命中一次。怎么回事？

Answer 1

虽然文档中的示例显示处理程序安装在main() 的开头，但这对于自动测试来说是不够的。似乎 Qt 本身在自动测试的生命周期中安装了其他消息处理程序，并且这些处理程序的安装时间比测试的构造函数晚了很多。如果您通过放置断点 here 从源代码构建 Qt，您可以自己验证这一点。

一旦创建测试本身（在QTEST_APPLESS_MAIN 宏内），Qt 的测试日志基础架构就会安装自己的消息处理程序。

如果您在 Creator 中使用 QML 调试，那么它也会安装自己的消息处理程序。

要解决这个问题，请尽可能晚地安装您的处理程序：

#include <QtTest>

class AutoTest : public QObject
{
    Q_OBJECT

public:
    AutoTest();
    ~AutoTest();

private slots:
    void initTestCase();
    void test_case1();

};

static QtMessageHandler oldMessageHandler;

// Exits on warnings
void warningMessageHandler(QtMsgType type, const QMessageLogContext &context, const QString &msg)
{
    QByteArray localMsg = msg.toLocal8Bit();
    const char *file = context.file ? context.file : "";
    const char *function = context.function ? context.function : "";
    switch (type) {
    case QtWarningMsg:
        fprintf(stderr, "EXITING - TEST FAILED DUE TO WARNING: %s (%s:%u, %s)\n", localMsg.constData(), file, context.line, function);
        exit(1);
    default:
        oldMessageHandler(type, context, msg);
    }
}

AutoTest::AutoTest()
{
}

AutoTest::~AutoTest()
{

}

void AutoTest::initTestCase()
{
    oldMessageHandler = qInstallMessageHandler(warningMessageHandler);
}

void AutoTest::test_case1()
{
    qWarning() << "This should cause the application to exit with code 1";
}

QTEST_APPLESS_MAIN(AutoTest)

#include "tst_autotest.moc"

请务必调用之前安装的消息处理程序，以免丢失 Qt 日志记录提供的任何功能。

这个输出：

17:44:44: Starting /Users/mitch/dev/temp/autotest-qt5_14_fw-Debug/autotest.app/Contents/MacOS/autotest ...
********* Start testing of AutoTest *********
Config: Using QtTest library 5.14.0, Qt 5.14.0 (x86_64-little_endian-lp64 shared (dynamic) debug build; by Clang 10.0.0 (clang-1000.11.45.2) (Apple))
EXITING - TEST FAILED DUE TO WARNING: This should cause the application to exit with code 1 (../autotest/tst_autotest.cpp:50, void AutoTest::test_case1())
PASS   : AutoTest::initTestCase()
17:44:44: /Users/mitch/dev/temp/autotest-qt5_14_fw-Debug/autotest.app/Contents/MacOS/autotest exited with code 1