fix tests failing (for now)

hypothesis introduced a regression in 3.29.0 (or at least changed
behaviour). Until I have found the problem I will pin it to the last
working version.

Also two tests should be prevented from failing when they are slow.

setup.py

@@ -132,7 +132,7 @@ setup(
         'nose',
         'scripttest',
         'mock',
-        'hypothesis',
+        'hypothesis<=3.28.3',
         'flake8'
     ],
     cmdclass={'test': Tox},

test/test_printer_file.py

@@ -16,7 +16,7 @@ from __future__ import unicode_literals
 import six
 
 import pytest
-from hypothesis import given
+from hypothesis import given, settings
 from hypothesis.strategies import text
 
 import escpos.printer as printer
@@ -37,6 +37,7 @@ def test_load_file_printer(mocker, path):
     mock_open.assert_called_with(path, "wb")
 
 
+@settings(deadline=None)
 @given(txt=text())
 def test_auto_flush(mocker, txt):
     """test auto_flush in file-printer"""
@@ -57,6 +58,7 @@ def test_auto_flush(mocker, txt):
     assert mock_device.flush.called
 
 
+@settings(deadline=None)
 @given(txt=text())
 def test_flush_on_close(mocker, txt):
     """test flush on close in file-printer"""

tox.ini

@@ -10,7 +10,7 @@ deps = nose
        pytest!=3.2.0
        pytest-cov
        pytest-mock
-       hypothesis
+       hypothesis<=3.28.3
        viivakoodi
 commands = py.test --cov escpos