Switched precedence of power and functions, and added some unit tests for it...

Switched precedence of power and functions, and added some unit tests for it (corresponding to WolframAlpha's output).

src/parser.py

@@ -63,8 +63,8 @@ class Parser(BisonParser):
         ('left', ('TIMES', 'DIVIDE')),
         ('left', ('EQ', )),
         ('left', ('NEG', )),
-        ('right', ('SIN', 'COS', 'TAN', 'SOLVE', 'INT', 'SQRT')),
         ('right', ('POW', )),
+        ('right', ('SIN', 'COS', 'TAN', 'SOLVE', 'INT', 'SQRT')),
         )
 
     interactive = 0

tests/test_parser.py

@@ -4,6 +4,8 @@ import unittest
 from src.parser import Parser
 from src.node import ExpressionNode as Node, ExpressionLeaf as Leaf
 from tests.parser import ParserWrapper, run_expressions, line, graph
+from tests.rulestestcase import tree
+from src.rules.goniometry import sin, cos
 
 
 class TestParser(unittest.TestCase):
@@ -15,11 +17,11 @@ class TestParser(unittest.TestCase):
         run_expressions(Parser, [('a', Leaf('a'))])
 
     def test_graph(self):
-        assert graph(Parser, '4a') == ("""
+        self.assertEqual(graph(Parser, '4a'), ("""
          *
         ╭┴╮
         4 a
-        """).replace('\n        ', '\n')[1:-1]
+        """).replace('\n        ', '\n')[1:-1])
 
     def test_line(self):
         self.assertEqual(line(Parser, '4-a'), '4 - a')
@@ -35,3 +37,14 @@ class TestParser(unittest.TestCase):
         self.assertNotEqual(possibilities2, [])
 
         self.assertNotEqual(possibilities1, possibilities2)
+
+    def test_functions(self):
+        root, x = tree('sin x, x')
+
+        self.assertEqual(root, sin(x))
+        self.assertEqual(tree('sin x ^ 2'), sin(x) ** 2)
+        self.assertEqual(tree('sin(x) ^ 2'), sin(x) ** 2)
+        self.assertEqual(tree('sin (x) ^ 2'), sin(x) ** 2)
+        self.assertEqual(tree('sin(x ^ 2)'), sin(x ** 2))
+        self.assertEqual(tree('sin cos x'), sin(cos(x)))
+        self.assertEqual(tree('sin cos x ^ 2'), sin(cos(x)) ** 2)