Fix rewrite to not write past the edge of the screen

Author: nicoddemus

_pytest/terminal.py

@@ -214,7 +214,7 @@ def rewrite(self, line, **markup):
         """
         erase = markup.pop('erase', False)
         if erase:
-            fill_count = self.writer.fullwidth - len(line)
+            fill_count = self.writer.fullwidth - len(line) - 1
             fill = ' ' * fill_count
         else:
             fill = ''

testing/test_terminal.py

@@ -222,7 +222,7 @@ def test_rewrite(self, testdir, monkeypatch):
         tr.writer.fullwidth = 10
         tr.write('hello')
         tr.rewrite('hey', erase=True)
-        assert f.getvalue() == 'hello' + '\r' + 'hey' + (7 * ' ')
+        assert f.getvalue() == 'hello' + '\r' + 'hey' + (6 * ' ')
 
 
 class TestCollectonly(object):