Fixed EOL formatting on tests to make them pass

The unit tests for exporting XML were too brittle, they were breaking
because of the wrong line endings, using an IDE 'phpstorm' to apply
coding standards changing the expected line endings from that of the
actual line endings. I have changed the unit tests to specify the line
endings with a class constant so editing the unit tests file on a
different OS will not convert the expected line endings in the unit
test.