Introduce QSignalSpy constructor allows to spy on a meta method

This functionality is especially convenient if meta-object system is
heavily used in a test. For example, if you need to test a bunch of
signals based on their names and/or argument types.

Change-Id: I09a4ecbbd3d0859b5fd466d9dde7679804eb7614
Reviewed-by: Volker Hilsheimer <volker.hilsheimer@qt.io>

1 files changed, 22 insertions, 0 deletions

diff --git a/src/testlib/qsignalspy.qdoc b/src/testlib/qsignalspy.qdoc
index 3352307d69..5ea6bc5dc7 100644
--- a/src/testlib/qsignalspy.qdoc
+++ b/src/testlib/qsignalspy.qdoc
@@ -86,6 +86,28 @@
     \snippet code/doc_src_qsignalspy.cpp 6
 */
 
+/*! \fn QSignalSpy(const QObject *obj, const QMetaMethod &signal)
+    \since 5.14
+
+    Constructs a new QSignalSpy that listens for emissions of the \a signal
+    from the QObject \a object. If QSignalSpy is not able to listen for a
+    valid signal (for example, because \a object is \nullptr or \a signal does
+    not denote a valid signal of \a object), an explanatory warning message
+    will be output using qWarning() and subsequent calls to \c isValid() will
+    return false.
+
+    This constructor is convenient to use when Qt's meta-object system is
+    heavily used in a test.
+
+    Basic usage example:
+    \snippet code/doc_src_qsignalspy.cpp 7
+
+    Imagine we need to check whether all properties of the QWindow class
+    that represent minimum and maximum dimensions are properly writable.
+    The following example demonstrates one of the approaches:
+    \snippet code/doc_src_qsignalspy.cpp 8
+*/
+
 /*! \fn QSignalSpy::isValid() const
 
     Returns \c true if the signal spy listens to a valid signal, otherwise false.