diff --git a/beat/backend/python/test/prefix/databases/syntax_error/1.py b/beat/backend/python/test/prefix/databases/syntax_error/1.py
index 22c785c22473f7a4e51e6b8db7cc3bf331d28465..9a616fa17d6d1d00a0e98105cb8cf99d2c91aab0 100755
--- a/beat/backend/python/test/prefix/databases/syntax_error/1.py
+++ b/beat/backend/python/test/prefix/databases/syntax_error/1.py
@@ -36,6 +36,7 @@
 
 from beat.backend.python.database import View
 
+
 class SyntaxError(View); # <-- syntax error!
 
     def get(self, output, index):
diff --git a/beat/backend/python/test/test_format_simple.py b/beat/backend/python/test/test_format_simple.py
index 5538b72b774cd206fbe5562b5a2e2c1dbcbf3839..7d0d4f24e3d665e42e0e193c861941b4742cee6b 100644
--- a/beat/backend/python/test/test_format_simple.py
+++ b/beat/backend/python/test/test_format_simple.py
@@ -56,23 +56,23 @@ def test_integers():
     nose.tools.assert_true(numpy.issubdtype(ftype.value64, numpy.int64))
 
     obj = ftype(
-        value8=numpy.int8(2 ** 6),
-        value16=numpy.int16(2 ** 14),
-        value32=numpy.int32(2 ** 30),
-        value64=numpy.int64(2 ** 62),
+        value8=numpy.int8(2**6),
+        value16=numpy.int16(2**14),
+        value32=numpy.int32(2**30),
+        value64=numpy.int64(2**62),
     )
 
     nose.tools.eq_(obj.value8.dtype, numpy.int8)
-    nose.tools.eq_(obj.value8, 2 ** 6)
+    nose.tools.eq_(obj.value8, 2**6)
 
     nose.tools.eq_(obj.value16.dtype, numpy.int16)
-    nose.tools.eq_(obj.value16, 2 ** 14)
+    nose.tools.eq_(obj.value16, 2**14)
 
     nose.tools.eq_(obj.value32.dtype, numpy.int32)
-    nose.tools.eq_(obj.value32, 2 ** 30)
+    nose.tools.eq_(obj.value32, 2**30)
 
     nose.tools.eq_(obj.value64.dtype, numpy.int64)
-    nose.tools.eq_(obj.value64, 2 ** 62)
+    nose.tools.eq_(obj.value64, 2**62)
 
     # checks JSON enconding
     copy = ftype()
@@ -103,7 +103,7 @@ def test_integers_unsafe_cast():
     ftype = df.type
 
     obj = ftype()
-    obj.from_dict(dict(value8=2 ** 6), casting="safe", add_defaults=True)
+    obj.from_dict(dict(value8=2**6), casting="safe", add_defaults=True)
 
 
 # ----------------------------------------------------------
@@ -121,23 +121,23 @@ def test_unsigned_integers():
     nose.tools.assert_true(numpy.issubdtype(ftype.value64, numpy.uint64))
 
     obj = ftype(
-        value8=numpy.uint8(2 ** 6),
-        value16=numpy.uint16(2 ** 14),
-        value32=numpy.uint32(2 ** 30),
-        value64=numpy.uint64(2 ** 62),
+        value8=numpy.uint8(2**6),
+        value16=numpy.uint16(2**14),
+        value32=numpy.uint32(2**30),
+        value64=numpy.uint64(2**62),
     )
 
     nose.tools.eq_(obj.value8.dtype, numpy.uint8)
-    nose.tools.eq_(obj.value8, 2 ** 6)
+    nose.tools.eq_(obj.value8, 2**6)
 
     nose.tools.eq_(obj.value16.dtype, numpy.uint16)
-    nose.tools.eq_(obj.value16, 2 ** 14)
+    nose.tools.eq_(obj.value16, 2**14)
 
     nose.tools.eq_(obj.value32.dtype, numpy.uint32)
-    nose.tools.eq_(obj.value32, 2 ** 30)
+    nose.tools.eq_(obj.value32, 2**30)
 
     nose.tools.eq_(obj.value64.dtype, numpy.uint64)
-    nose.tools.eq_(obj.value64, 2 ** 62)
+    nose.tools.eq_(obj.value64, 2**62)
 
     # checks JSON enconding
     copy = ftype()
@@ -168,7 +168,7 @@ def test_unsigned_integers_unsafe_cast():
     ftype = df.type
 
     obj = ftype()
-    obj.from_dict(dict(value8=2 ** 6), casting="safe", add_defaults=True)
+    obj.from_dict(dict(value8=2**6), casting="safe", add_defaults=True)
 
 
 # ----------------------------------------------------------
@@ -183,7 +183,7 @@ def test_unsigned_integers_missing_attributes():
     ftype = df.type
 
     obj = ftype()
-    obj.from_dict(dict(value8=2 ** 6), casting="safe", add_defaults=False)
+    obj.from_dict(dict(value8=2**6), casting="safe", add_defaults=False)
 
 
 # ----------------------------------------------------------
diff --git a/beat/backend/python/test/test_hash.py b/beat/backend/python/test/test_hash.py
index 809de4596f4f3a370014e8e8599647fc722b4e47..c9dbbd02b68316d18582a16bdfbf23d30f88bc25 100644
--- a/beat/backend/python/test/test_hash.py
+++ b/beat/backend/python/test/test_hash.py
@@ -86,7 +86,7 @@ def test_accented_hash():
 
 def test_unicode_hash():
     nose.tools.eq_(
-        hash._sha256(u"áéçü"),
+        hash._sha256("áéçü"),
         "477993339861be6552873127471f9da6ae443991d5aced735f51140c34cd7599",
     )