diff --git a/tests/test_raw.py b/tests/test_raw.py
index 2a608749f6ffa98bd90baaa4fc2306168cb2ea5d..f1704b83f11729ebd99c2fd0aed04cedc8417583 100644
--- a/tests/test_raw.py
+++ b/tests/test_raw.py
@@ -109,7 +109,7 @@ def test_scalarmult():
     assert len(x) == 32
     y, ypub = secret_scalar()
     # the Curve25519 base point (generator)
-    base = unhexlify(b"09" + b"00"*31)
+    base = unhexlify(b"09" + b"00" * 31)
 
     bx1 = c.crypto_scalarmult_base(x)
     bx2 = c.crypto_scalarmult(x, base)
@@ -120,7 +120,7 @@ def test_scalarmult():
     ybx = c.crypto_scalarmult(y, c.crypto_scalarmult_base(x))
     assert tohex(xby) == tohex(ybx)
 
-    z = unhexlify(b"10"*32)
+    z = unhexlify(b"10" * 32)
     bz1 = c.crypto_scalarmult_base(z)
     assert tohex(bz1) == ("781faab908430150daccdd6f9d6c5086"
                           "e34f73a93ebbaa271765e5036edfc519")
diff --git a/tox.ini b/tox.ini
index 68b0fd850dac390ac274985f6c49bcf6bb9ac455..0d81ee4491ea92fbd40c36b9976f9fa786d00956 100644
--- a/tox.ini
+++ b/tox.ini
@@ -24,4 +24,5 @@ deps = flake8
 commands = flake8 .
 
 [flake8]
+select = E,W,F
 exclude = .tox,*.egg