Improve usage of the break state for the Tx line

1. Now the sendBreak() method is deprecated since it is blocking and
impossible to implement same behavior on different platforms using
their API's. Besides, this method can be implemented via
setBreakEnabled() and QTimer.

2. Introduced the new property named as "breakEnabled" which consist
of setBreakEnabled() and isBreakEnabled() methods and the signal
breakEnabledChanged().

Note: After opening, the port always is in non-break state.

Task-number: QTBUG-36571
Change-Id: Ib808dab7eaed8cc5449c66d8186a29a7b7e45afc
Reviewed-by: Denis Shienkov <denis.shienkov@gmail.com>

1 files changed, 59 insertions, 0 deletions

diff --git a/tests/auto/qserialport/tst_qserialport.cpp b/tests/auto/qserialport/tst_qserialport.cpp
index b05d7d0..0ebeb0a 100644
--- a/tests/auto/qserialport/tst_qserialport.cpp
+++ b/tests/auto/qserialport/tst_qserialport.cpp
@@ -112,6 +112,8 @@ private slots:
     void readAfterInputClear();
 #endif
 
+    void controlBreak();
+
 protected slots:
     void handleBytesWrittenAndExitLoopSlot(qint64 bytesWritten);
     void handleBytesWrittenAndExitLoopSlot2(qint64 bytesWritten);
@@ -750,5 +752,62 @@ void tst_QSerialPort::readAfterInputClear()
 }
 #endif
 
+class BreakReader : public QObject
+{
+    Q_OBJECT
+public:
+    explicit BreakReader(QSerialPort &port)
+        : serialPort(port)
+    {
+        connect(&serialPort, SIGNAL(readyRead()), this, SLOT(receive()));
+    }
+
+private slots:
+    void receive()
+    {
+        tst_QSerialPort::exitLoop();
+    }
+
+private:
+    QSerialPort &serialPort;
+};
+
+void tst_QSerialPort::controlBreak()
+{
+#ifdef Q_OS_WIN
+    clearReceiver();
+#endif
+
+    QSerialPort senderPort(m_senderPortName);
+    QVERIFY(senderPort.open(QSerialPort::WriteOnly));
+    QCOMPARE(senderPort.isBreakEnabled(), false);
+
+    QSignalSpy breakSpy(&senderPort, SIGNAL(breakEnabledChanged(bool)));
+    QVERIFY(breakSpy.isValid());
+
+    QSerialPort receiverPort(m_receiverPortName);
+    QVERIFY(receiverPort.open(QSerialPort::ReadOnly));
+
+    BreakReader reader(receiverPort);
+
+    QVERIFY(senderPort.setBreakEnabled(true));
+    QCOMPARE(senderPort.isBreakEnabled(), true);
+
+    enterLoop(1);
+    QVERIFY2(!timeout(), "Timed out when waiting for the read of break state.");
+    QVERIFY(receiverPort.bytesAvailable() > 0);
+
+    foreach (const char c, receiverPort.readAll()) {
+        QCOMPARE(c, char(0));
+    }
+
+    QVERIFY(senderPort.setBreakEnabled(false));
+    QCOMPARE(senderPort.isBreakEnabled(), false);
+
+    QCOMPARE(breakSpy.count(), 2);
+    QCOMPARE(qvariant_cast<bool>(breakSpy.at(0).at(0)), true);
+    QCOMPARE(qvariant_cast<bool>(breakSpy.at(1).at(0)), false);
+}
+
 QTEST_MAIN(tst_QSerialPort)
 #include "tst_qserialport.moc"