Writing tests.

I'm backfilling tests to cover the functionality that I developed
incrementally in the Jupyter notebook and nail it down with concrete
examples.  No doubt I'll uncover some bugs.

test/test_type_inference.py

@@ -0,0 +1,84 @@
+#!/usr/bin/env python
+import unittest
+
+from joy.utils.polytypes import *
+from joy.utils.stack import list_to_stack as __
+
+
+kv = lambda e: kav(__(e))
+
+
+globals().update(SYMBOLS)
+globals().update(COMBINATORS)
+
+
+class TestKleeneStar(unittest.TestCase):
+    
+  def test_sum(self):
+    expression = [
+      (n1, (n2, (n3, s1))),  # Three numbers in a stack.
+      sum,  # builtin shadowed by SymbolJoyType
+      ]
+    # A function that puts a single number on the stack.
+    f = s0, (n0, s0)
+    self.assertEqual(kv(expression), [f])
+
+  def test_BS(self):
+    expression = pop, swap, rolldown, rest, rest, cons, cons
+    # ([a3 a4 ...0] a2 a1 a0 -- [a1 a2 ...0])
+    f = (a0, (a1, (a2, ((a3, (a4, s0)), s1)))), ((a1, (a2, s0)), s1)
+    self.assertEqual(kv(expression), [f])
+
+  def test_enter(self):
+    expression = a1, (cons, s0), dip  # a1 [cons] dip
+    # (a0 [...0] -- [a0 ...0] a1)
+    f = ((s0, (a0, s1)), (a1, ((a0, s0), s1)))
+    self.assertEqual(kv(expression), [f])
+
+  def test_2(self):
+    # [cons] i == cons
+    expression = (cons, s0), i
+    self.assertEqual(kv(expression), kv([cons]))
+
+
+##
+##for g in MC(dup, mul):
+##    print doc_from_stack_effect(*g)
+
+
+##    print doc_from_stack_effect(*f)
+##    print 
+##    for sec in kav(e):
+##      print sec, doc_from_stack_effect(*sec)
+##        self.assertRaises(KeyError, lambda: {}[23])
+##    def test_leave(self):
+##    def setUp(self):
+##    def tearDown(self):
+
+
+
+##DIP = CombinatorJoyType('dip', [dip], 44)
+##DIPD = CombinatorJoyType('dipd', [dipd], 45)
+
+##l = [(s0, ((CONS, s2), (A[1], s0)))]
+##
+##e = (DIP, ())
+##
+##h = kav(e, l[0])
+##
+##for z in h:
+##  print doc_from_stack_effect(*z)
+
+##
+##
+##
+##
+##
+##expression = (a1, (a3, ((CONS, s0), (DIPD, ()))))
+##
+##for sec in kav(expression):
+##  print doc_from_stack_effect(*sec)
+##
+
+if __name__ == '__main__':
+    unittest.main()