Update test function to take an argument

test.py

@@ -0,0 +1,42 @@
+# test.py
+# ----------
+# By MWC Contributors
+#
+# Tests one letter in `typeface`. This testing script will be very useful
+# as you work on one letter at a time. This program requires one argument, 
+# the letter you want to test. For example: 
+#
+#   python test.py q
+
+from turtle import *
+from grid import draw_grid
+from argparse import ArgumentParser
+from superturtle.movement import no_delay
+import typeface
+
+UNIT = 40
+GRID_COLOR = "lightgrey"
+GRID_SIZE = 1
+LETTER_COLOR = "black"
+LETTER_SIZE = 3
+
+parser = ArgumentParser("Test a letter in your typeface.")
+parser.add_argument("letter")
+arguments = parser.parse_args()
+letter_function_name = "draw_letter_" + arguments.letter
+letter_function = getattr(typeface, letter_function_name)
+
+penup()
+goto(-160, -160)
+pendown()
+
+with no_delay():
+    color(GRID_COLOR)
+    pensize(GRID_SIZE)
+    draw_grid(UNIT)
+
+color(LETTER_COLOR)
+pensize(LETTER_SIZE)
+letter_function(UNIT)
+
+input()

testing.py

@@ -1,33 +0,0 @@
-# testing.py
-# By Chris Proctor
-#
-# Tests one letter in `typeface`. This testing script will be very useful
-# as you work on one letter at a time. If you want to change which letter
-# is tested, edit line 31 below. 
-# 
-
-from turtle import *
-from grid import draw_grid
-from superturtle.movement import no_delay
-import typeface
-
-UNIT = 40
-GRID_COLOR = "lightgrey"
-GRID_SIZE = 1
-LETTER_COLOR = "black"
-LETTER_SIZE = 3
-
-penup()
-goto(-160, -160)
-pendown()
-
-with no_delay():
-    color(GRID_COLOR)
-    pensize(GRID_SIZE)
-    draw_grid(UNIT)
-
-color(LETTER_COLOR)
-pensize(LETTER_SIZE)
-typeface.draw_letter_a(UNIT)
-
-input()