finish corr flake8 in calculus

pymath/calculus/test/test_expression.py

@@ -5,9 +5,6 @@
 
 
 from pymath.calculus.expression import Expression
-from pymath.calculus.fraction import Fraction
-from pymath.calculus.generic import first_elem
-from pymath.calculus.render import txt, tex
 from pymath.calculus.operator import op
 
 

pymath/calculus/test/test_render.py

@@ -4,7 +4,7 @@
 
 import unittest
 
-from pymath.calculus.render import tex, txt, p2i
+from pymath.calculus.render import tex, txt
 from pymath.calculus.fraction import Fraction
 from pymath.calculus.polynom import Polynom
 from pymath.calculus.operator import op

pymath/calculus/test/test_str2tokens.py

@@ -57,7 +57,7 @@ class TestStr2tokens(unittest.TestCase):
         post = str2in_tokens(exp)
         self.assertEqual(post, [Polynom([0, 1]), "*", Polynom([0, 1]), '+', 4])
 
-    def test_str2tokens_poly(self):
+    def test_str2tokens_poly_par(self):
         exp = "x(2+1) + 4"
         post = str2in_tokens(exp)
         self.assertEqual(post, [Polynom([0, 1]), "*",