如果出现警告，如何立即使自动测试失败

Question

当测试代码中打印警告时，我想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。

我想我可以用qInstallMessageHandler()来做这件事。我从这里修改了示例：

#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，测试应用程序不会按预期提前退出：

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

我在消息处理程序函数中放置了一个断点，它一次也没有命中。这是怎么回事？

Answer 1

尽管文档中的示例显示了在main()开始时安装的处理程序，但这不足以进行自动测试。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，并且这些消息处理程序的安装时间比测试的构造函数晚得多。如果您从源代码构建了Qt，则可以在此处放置断点来自己验证这一点。

Qt的测试日志记录基础设施会在创建测试本身后立即安装自己的消息处理程序(在QTEST_APPLESS_MAIN宏中(。

如果您在 Creator 中使用 QML 调试，那么它还将安装自己的消息处理程序。

要解决此问题，请尽可能晚地安装处理程序：

#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"

请务必调用以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