Separate method open() and constructor, enhance consistency between connectors: Rework printer tests (#587)

* Add fixtures
* Add test_printer_file.py
* Remove old broken printer tests
* Include a close_on_reopen test
* Add test_printer_network.py
* Add test_printer_serial.py
* Add test_printer_usb.py
* Add test_printer_lp.py
* Add test_printer_cups.py
* Add test_printer_win32raw.py
* Test the 'printers' property
* Fix conftest import formatting
* Fix failing LP tests
* Cancel close only if literal False|None _device
* Fix win32raw failing tests (maybe)
* Include win32raw close_on_reopen test
* Include test _raw methods to win32raw
* Replace general exceptions in win32raw
* Replace wrong exception in cups
* Include more tests to cups
* Extend cups tests

test/conftest.py

@@ -1,8 +1,49 @@
 import pytest
 
-from escpos.printer import Dummy
+from escpos.exceptions import DeviceNotFoundError
+from escpos.printer import LP, CupsPrinter, Dummy, File, Network, Serial, Usb, Win32Raw
 
 
 @pytest.fixture
 def driver():
     return Dummy()
+
+
+@pytest.fixture
+def usbprinter():
+    return Usb()
+
+
+@pytest.fixture
+def serialprinter():
+    return Serial()
+
+
+@pytest.fixture
+def networkprinter():
+    return Network()
+
+
+@pytest.fixture
+def fileprinter():
+    return File()
+
+
+@pytest.fixture
+def lpprinter():
+    return LP()
+
+
+@pytest.fixture
+def win32rawprinter():
+    return Win32Raw()
+
+
+@pytest.fixture
+def cupsprinter():
+    return CupsPrinter()
+
+
+@pytest.fixture
+def devicenotfounderror():
+    return DeviceNotFoundError