new unittest for expression

pymath/expression.py

@@ -111,7 +111,7 @@ class Expression(object):
     ## ---------------------
     ## String parsing
 
-    ## @classmethod ????
+    @classmethod
     def str2tokens(self, exp):
         """ Parse the expression, ie tranform a string into a list of tokens
 

test/test_expression.py

@@ -8,13 +8,16 @@ import unittest
 from pymath.expression import Expression
 from pymath.fraction import Fraction
 from pymath.generic import first_elem
+from pymath.renders import txt_render
 
 
 class TestExpression(unittest.TestCase):
     """Testing functions from pymath.expression"""
 
-    def test_init_from_exp(self):
+    def test_init_from_str(self):
-        pass
+        exp = Expression("2 + 3")
+        self.assertEqual(exp.infix_tokens, [2, "+", 3])
+        self.assertEqual(exp.postfix_tokens, [2, 3, "+"])
 
     def test_init_from_exp(self):
         pass
@@ -25,6 +28,30 @@ class TestExpression(unittest.TestCase):
     def test_postfix_tokens(self):
         pass
 
+    def test_str2tokens_big_num(self):
+        exp = "123 + 3"
+        tok = Expression.str2tokens(exp)
+        self.assertEqual(tok, [123, "+", 3])
+
+    def test_str2tokens_beg_minus(self):
+        exp = "-123 + 3"
+        tok = Expression.str2tokens(exp)
+        self.assertEqual(tok, [-123, "+", 3])
+
+    def test_str2tokens_time_lack(self):
+        exp = "(-3)(2)"
+        tok = Expression.str2tokens(exp)
+        self.assertEqual(tok, ["(", -3, ")", "*","(", 2, ")" ])
+
+    def test_str2tokens_time_lack2(self):
+        exp = "-3(2)"
+        tok = Expression.str2tokens(exp)
+        self.assertEqual(tok, [-3, "*","(", 2, ")" ])
+
+    def test_str2tokens_error(self):
+        exp = "1 + $"
+        self.assertRaises(ValueError, Expression.str2tokens, exp)
+
     def test_doMath(self):
         ops = [\
                 {"op": ("+", 1 , 2), "res" : 3}, \
@@ -43,6 +70,16 @@ class TestExpression(unittest.TestCase):
     def test_isOperator(self):
         pass
 
+    def test_simplify_frac(self):
+        exp = Expression("1/2 - 4")
+        steps = ["[1, 2, '/', 4, '-']", \
+                "[< Fraction 1 / 2>, 4, '-']", \
+                "[1, 1, '*', 2, 1, '*', '/', 4, 2, '*', 1, 2, '*', '/', '-']", \
+                "[1, 8, '-', 2, '/']", \
+                '[< Fraction -7 / 2>]']
+        self.assertEqual(steps, list(exp.simplify()))
+
+
 if __name__ == '__main__':
     unittest.main()