tests: fix test_example_app
tests: fix test_example_app

Signed-off-by: Sebastian Witowski <139b56c0e02b2c22f4e756593dbc8e818fe05596@gmail.com>

inveniosoftware/invenio-formatter,inveniosoftware/invenio-formatter,tiborsimko/invenio-formatter,inveniosoftware/invenio-formatter,tiborsimko/invenio-formatter,tiborsimko/invenio-formatter