Method testReadFromEnd02

tests/livedata/LiveDataTest.cpp:811–901

! * read from the end of the new data, read 1 sample, keep 2 samples only */

 * read from the end of the new data, read 1 sample, keep 2 samples only
 */
void LiveDataTest::testReadFromEnd02() {
	// create a temp file and write some data into it
	QTemporaryFile tempFile;
	if (!tempFile.open())
		QFAIL("failed to create the temp file for writing");

	QFile file(tempFile.fileName());
	if (!file.open(QIODevice::ReadWrite | QIODevice::Truncate | QIODevice::Text))
		QFAIL("failed to open the temp file for writing");

	file.write("1,2\n3,4\n");
	file.flush();

	// initialize the live data source
	LiveDataSource dataSource(QStringLiteral("test"), false);
	dataSource.setSourceType(LiveDataSource::SourceType::FileOrPipe);
	dataSource.setFileType(AbstractFileFilter::FileType::Ascii);
	dataSource.setFileName(file.fileName());
	dataSource.setReadingType(LiveDataSource::ReadingType::FromEnd);
	dataSource.setSampleSize(1);
	dataSource.setKeepNValues(2);
	dataSource.setUpdateType(LiveDataSource::UpdateType::NewData);

	// initialize the ASCII filter
	auto* filter = new AsciiFilter();
	auto properties = filter->defaultProperties();
	properties.headerEnabled = false;
	properties.intAsDouble = false;
	properties.columnNamesRaw = QStringLiteral("x, y");
	properties.columnModesString = QStringLiteral("Int, Int");
	properties.automaticSeparatorDetection = false;
	properties.separator = QStringLiteral(",");
	QCOMPARE(filter->initialize(properties), AsciiFilter::Status::Success);
	dataSource.setFilter(filter);

	// read the data and perform checks, after the initial read all data is read
	dataSource.read();

	QCOMPARE(dataSource.columnCount(), 2);
	QCOMPARE(dataSource.rowCount(), 1);

	QCOMPARE(dataSource.column(0)->columnMode(), AbstractColumn::ColumnMode::Integer);
	QCOMPARE(dataSource.column(1)->columnMode(), AbstractColumn::ColumnMode::Integer);

	QCOMPARE(dataSource.column(0)->integerAt(0), 1);
	QCOMPARE(dataSource.column(1)->integerAt(0), 2);

	dataSource.read();

	QCOMPARE(dataSource.columnCount(), 2);
	QCOMPARE(dataSource.rowCount(), 2);

	QCOMPARE(dataSource.column(0)->columnMode(), AbstractColumn::ColumnMode::Integer);
	QCOMPARE(dataSource.column(1)->columnMode(), AbstractColumn::ColumnMode::Integer);

	QCOMPARE(dataSource.column(0)->integerAt(0), 1);
	QCOMPARE(dataSource.column(1)->integerAt(0), 2);