linux: custom terminal settings replacing setraw

fixes #64, as described there, the raw terminal can produce a lot of
unneeded whitespace. Using the new configuration it seem to behave as
expected.

readchar/_posix_read.py

@@ -1,19 +1,24 @@
 import sys
 import termios
-import tty
 
 
 # Initially taken from:
 # http://code.activestate.com/recipes/134892/
 # Thanks to Danny Yoo
+# more infos from:
+# https://gist.github.com/michelbl/efda48b19d3e587685e3441a74457024
+# Thanks to Michel Blancard
 def readchar() -> str:
     """Reads a single character from the input stream.
     Blocks until a character is available."""
 
     fd = sys.stdin.fileno()
     old_settings = termios.tcgetattr(fd)
+    term = termios.tcgetattr(fd)
     try:
-        tty.setraw(sys.stdin.fileno())
+        term[3] &= ~(termios.ICANON | termios.ECHO | termios.IGNBRK | termios.BRKINT)
+        termios.tcsetattr(fd, termios.TCSAFLUSH, term)
+
         ch = sys.stdin.read(1)
     finally:
         termios.tcsetattr(fd, termios.TCSADRAIN, old_settings)

tests/posix/conftest.py

@@ -3,7 +3,6 @@
 
 if sys.platform.startswith("linux"):
     import termios
-    import tty
 
 
 # ignore all tests in this folder if not on linux
@@ -33,13 +32,9 @@ def mock_tcgetattr(fd):
     def mock_tcsetattr(fd, TCSADRAIN, old_settings):
         return None
 
-    def mock_setraw(fd):
-        return None
-
     mock = mocked_stdin()
     with pytest.MonkeyPatch.context() as mp:
         mp.setattr(sys.stdin, "read", mock.read)
         mp.setattr(termios, "tcgetattr", mock_tcgetattr)
         mp.setattr(termios, "tcsetattr", mock_tcsetattr)
-        mp.setattr(tty, "setraw", mock_setraw)
         yield mock