diff --git a/test/test_expression.py b/test/test_expression.py
index d8f6eb6..003e986 100644
--- a/test/test_expression.py
+++ b/test/test_expression.py
@@ -1,63 +1,77 @@
 #!/usr/bin/env python
 # encoding: utf-8
 
+""" Testing Expression """
 
 
-import unittest
-
 from pymath.expression import Expression
 from pymath.fraction import Fraction
 from pymath.generic import first_elem
 from pymath.render import txt, tex
 
 
-class TestExpression(unittest.TestCase):
-    """Testing functions from pymath.expression"""
-
-    def setup(self):
-        Expression.set_render(txt)
-
-    def test_init_from_str(self):
+def test_init_from_str():
         exp = Expression("2 + 3")
-        self.assertEqual(exp.postfix_tokens, [2, 3, "+"])
+        assert exp.postfix_tokens == [2, 3, "+"]
 
-    def test_init_from_exp(self):
-        pass
+def test_init_from_exp():
+    pass
 
-    def test_list(self):
-        exp = Expression([2, 3, "+"])
-        self.assertEqual(exp.postfix_tokens, [2, 3, "+"])
+def test_init_list():
+    exp = Expression([2, 3, "+"])
+    assert exp.postfix_tokens == [2, 3, "+"]
 
-    def test_simplify_frac(self):
-        exp = Expression("1/2 - 4")
-        steps = ['\\frac{ 1 }{ 2 } - 4', \
-            '\\frac{ 1 \\times 1 }{ 2 \\times 1 } - \\frac{ 4 \\times 2 }{ 1 \\times 2 }',\
-            '\\frac{ 1 }{ 2 } - \\frac{ 8 }{ 2 }',\
-            '\\frac{ 1 - 8 }{ 2 }',\
-            '\\frac{ -7 }{ 2 }']
-        self.assertEqual(steps, list(exp.simplify()))
-        Expression.set_render(txt)
+def test_init_one_element_int_from_str():
+    exp = Expression("1")
 
-    def test_add_exp(self):
-        e = Expression("12- 4")
-        f = Expression("4 + 1")
-        g = e + f
-        self.assertEqual(g.postfix_tokens, [12, 4, '-', 4, 1, "+", "+"])
+def test_init_one_element_int_from_list():
+    exp = Expression([1])
 
-    def test_mul_exp(self):
-        e = Expression("12- 4")
-        f = Expression("4 + 1")
-        g = e * f
-        self.assertEqual(g.postfix_tokens, [12, 4, '-', 4, 1, "+", "*"])
+#def test_init_one_element_str_from_str():
+#    exp = Expression("x")
+#
+#def test_init_one_element_str_from_list():
+#    exp = Expression(["x"])
 
-    def test_neg_exp(self):
-        e = Expression("12- 4")
-        g = -e 
-        self.assertEqual(g.postfix_tokens, [12, 4, '-', '-'])
+def test_simplify_exp():
+    exp = Expression("1 + 2 * 3")
+    simplified = exp.simplify()
+    ans = Expression("7")
+    assert ans == simplified
 
+#def test_simplify_frac():
+#    exp = Expression("1/2 - 4")
+#    simplified = exp.simplify()
+#    ans = Expression("-7/2")
+#    assert simplified == ans
+#
+#def test_explain_frac():
+#    exp = Expression("1/2 - 4")
+#    simplified = exp.simplify()
+#
+#    steps = ['\\frac{ 1 }{ 2 } - 4', \
+#        '\\frac{ 1 \\times 1 }{ 2 \\times 1 } - \\frac{ 4 \\times 2 }{ 1 \\times 2 }',\
+#        '\\frac{ 1 }{ 2 } - \\frac{ 8 }{ 2 }',\
+#        '\\frac{ 1 - 8 }{ 2 }',\
+#        '\\frac{ -7 }{ 2 }']
+#    assert simplified.steps == list(exp.simplify())
 
-if __name__ == '__main__':
-    unittest.main()
+def test_add_exp():
+    e = Expression("12- 4")
+    f = Expression("4 + 1")
+    g = e + f
+    assert g.postfix_tokens == [12, 4, '-', 4, 1, "+", "+"]
+
+def test_mul_exp():
+    e = Expression("12- 4")
+    f = Expression("4 + 1")
+    g = e * f
+    assert g.postfix_tokens == [12, 4, '-', 4, 1, "+", "*"]
+
+def test_neg_exp():
+    e = Expression("12- 4")
+    g = -e 
+    assert g.postfix_tokens == [12, 4, '-', '-']
 
 
 # -----------------------------