Add QVERIFY_EXCEPTION_THROWN macro for testing exceptions using QtTest

New macro QVERIFY_EXCEPTION_THROWN may be used to check that some code
really throws an exception of specified type.

Change-Id: I7cf499c7c37a35407862bc604c6eb862c5f329d3
Reviewed-by: Friedemann Kleint <Friedemann.Kleint@digia.com>
Reviewed-by: Thiago Macieira <thiago.macieira@intel.com>
Reviewed-by: Jason McDonald <macadder1@gmail.com>

2 files changed, 64 insertions, 0 deletions

diff --git a/src/testlib/qtestcase.cpp b/src/testlib/qtestcase.cpp
index b09bd6701c..4abbb34986 100644
--- a/src/testlib/qtestcase.cpp
+++ b/src/testlib/qtestcase.cpp
@@ -165,6 +165,25 @@ QT_BEGIN_NAMESPACE
    \sa QVERIFY(), QTRY_COMPARE(), QTest::toString()
 */
 
+/*! \macro QVERIFY_EXCEPTION_THROWN(expression, exceptiontype)
+   \since 5.3
+
+   \relates QTest
+
+   The QVERIFY_EXCEPTION_THROWN macro executes an \a expression and tries
+   to catch an exception thrown from the \a expression. If the \a expression
+   throws an exception and its type is the same as \a exceptiontype
+   or \a exceptiontype is substitutable with the type of thrown exception
+   (i.e. usually the type of thrown exception is publically derived
+   from \a exceptiontype) then execution will be continued. If not-substitutable
+   type of exception is thrown or the \a expression doesn't throw an exception
+   at all, then a failure will be recorded in the test log and
+   the test won't be executed further.
+
+   \note This macro can only be used in a test function that is invoked
+   by the test framework.
+*/
+
 /*! \macro QTRY_VERIFY_WITH_TIMEOUT(condition, timeout)
    \since 5.0
 
diff --git a/src/testlib/qtestcase.h b/src/testlib/qtestcase.h
index 2a5d7d353b..f95a155ed9 100644
--- a/src/testlib/qtestcase.h
+++ b/src/testlib/qtestcase.h
@@ -51,6 +51,11 @@
 
 #include <string.h>
 
+#ifndef QT_NO_EXCEPTIONS
+#  include <exception>
+#endif // QT_NO_EXCEPTIONS
+
+
 QT_BEGIN_NAMESPACE
 
 class QRegularExpression;
@@ -84,6 +89,46 @@ do {\
         return;\
 } while (0)
 
+
+#ifndef QT_NO_EXCEPTIONS
+
+#  define QVERIFY_EXCEPTION_THROWN(expression, exceptiontype) \
+    do {\
+        QT_TRY {\
+            QT_TRY {\
+                expression;\
+                QTest::qFail("Expected exception of type " #exceptiontype " to be thrown" \
+                             " but no exception caught", __FILE__, __LINE__);\
+                return;\
+            } QT_CATCH (const exceptiontype &) {\
+            }\
+        } QT_CATCH (const std::exception &e) {\
+            QByteArray msg = QByteArray() + "Expected exception of type " #exceptiontype \
+                             " to be thrown but std::exception caught with message: " + e.what(); \
+            QTest::qFail(msg.constData(), __FILE__, __LINE__);\
+            return;\
+        } QT_CATCH (...) {\
+            QTest::qFail("Expected exception of type " #exceptiontype " to be thrown" \
+                         " but unknown exception caught", __FILE__, __LINE__);\
+            return;\
+        }\
+    } while (0)
+
+#else // QT_NO_EXCEPTIONS
+
+/*
+ * The expression passed to the macro should throw an exception and we can't
+ * catch it because Qt has been compiled without exception support. We can't
+ * skip the expression because it may have side effects and must be executed.
+ * So, users must use Qt with exception support enabled if they use exceptions
+ * in their code.
+ */
+#  define QVERIFY_EXCEPTION_THROWN(expression, exceptiontype) \
+    Q_STATIC_ASSERT_X(false, "Support of exceptions is disabled")
+
+#endif // !QT_NO_EXCEPTIONS
+
+
 // Will try to wait for the expression to become true while allowing event processing
 #define QTRY_VERIFY_WITH_TIMEOUT(__expr, __timeout) \
 do { \