Move code to get width of current line to a function

setup.py

@@ -59,7 +59,7 @@ def get_environment_marker_support_level():
 def main():
     extras_require = {}
     install_requires = [
-        "py>=1.5.0",
+        "py>=1.5.0",  # if py gets upgrade to >=1.6, remove _width_of_current_line in terminal.py
         "six>=1.10.0",
         "setuptools",
         "attrs>=17.4.0",

src/_pytest/terminal.py

@@ -412,11 +412,7 @@ class TerminalReporter(object):
             if last_item:
                 self._write_progress_information_filling_space()
             else:
-                try:
-                    w = self._tw.width_of_current_line
-                except AttributeError:
-                    # py < 1.6.0
-                    w = self._tw.chars_on_current_line
+                w = self._width_of_current_line
                 past_edge = w + self._PROGRESS_LENGTH + 1 >= self._screen_width
                 if past_edge:
                     msg = self._get_progress_information_message()
@@ -435,14 +431,19 @@ class TerminalReporter(object):
 
     def _write_progress_information_filling_space(self):
         msg = self._get_progress_information_message()
-        try:
-            w = self._tw.width_of_current_line
-        except AttributeError:
-            # py < 1.6.0
-            w = self._tw.chars_on_current_line
+        w = self._width_of_current_line
         fill = self._tw.fullwidth - w - 1
         self.write(msg.rjust(fill), cyan=True)
 
+    @property
+    def _width_of_current_line(self):
+        """Return the width of current line, using the superior implementation of py-1.6 when available"""
+        try:
+            return self._tw.width_of_current_line
+        except AttributeError:
+            # py < 1.6.0
+            return self._tw.chars_on_current_line
+
     def pytest_collection(self):
         if not self.isatty and self.config.option.verbose >= 1:
             self.write("collecting ... ", bold=True)