Test if we correctly detect errors when writing.

tests/FailDevice.cpp

@@ -0,0 +1,63 @@
+/*
+ *  Copyright (C) 2015 Felix Geyer <debfx@fobos.de>
+ *
+ *  This program is free software: you can redistribute it and/or modify
+ *  it under the terms of the GNU General Public License as published by
+ *  the Free Software Foundation, either version 2 or (at your option)
+ *  version 3 of the License.
+ *
+ *  This program is distributed in the hope that it will be useful,
+ *  but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *  GNU General Public License for more details.
+ *
+ *  You should have received a copy of the GNU General Public License
+ *  along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#include "FailDevice.h"
+
+FailDevice::FailDevice(int failAfter, QObject* parent)
+    : QBuffer(parent)
+    , m_failAfter(failAfter)
+    , m_readCount(0)
+    , m_writeCount(0)
+{
+}
+
+bool FailDevice::open(QIODevice::OpenMode openMode)
+{
+    return QBuffer::open(openMode | QIODevice::Unbuffered);
+}
+
+qint64 FailDevice::readData(char* data, qint64 len)
+{
+    if (m_readCount >= m_failAfter) {
+        setErrorString("FAILDEVICE");
+        return -1;
+    }
+    else {
+        qint64 result = QBuffer::readData(data, len);
+        if (result != -1) {
+            m_readCount += result;
+        }
+
+        return result;
+    }
+}
+
+qint64 FailDevice::writeData(const char* data, qint64 len)
+{
+    if (m_writeCount >= m_failAfter) {
+        setErrorString("FAILDEVICE");
+        return -1;
+    }
+    else {
+        qint64 result = QBuffer::writeData(data, len);
+        if (result != -1) {
+            m_writeCount += result;
+        }
+
+        return result;
+    }
+}