diff --git a/beat/core/test/test_format_load.py b/beat/core/test/test_format_load.py
index 9e253050cb09709ced48a75b904c6cc0dc0ae36f..b015d5b8f207ab0967abdf044fb02a751f144706 100644
--- a/beat/core/test/test_format_load.py
+++ b/beat/core/test/test_format_load.py
@@ -34,8 +34,6 @@
 ###################################################################################
 
 
-import os
-
 import six
 import numpy
 import nose.tools
@@ -49,31 +47,31 @@ from .utils import cleanup
 def test_load_default_format():
 
     df = DataFormat(prefix, data=None)
-    assert df.valid, "\n  * %s" % "\n  * ".join(df.errors)
+    nose.tools.assert_true(df.valid, "\n  * %s" % "\n  * ".join(df.errors))
 
 
 def test_load_unknown_format():
 
     df = DataFormat(prefix, "user/unknown/1")
-    assert df.valid is False
-    assert df.errors
+    nose.tools.assert_false(df.valid)
+    nose.tools.assert_true(df.errors)
     nose.tools.eq_(len(df.errors), 1)
-    assert df.errors[0].find("file not found") != -1
+    nose.tools.assert_not_equal(df.errors[0].find("file not found"), -1)
 
 
 def test_load_invalid_format():
 
     df = DataFormat(prefix, "user/invalid/1")
-    assert df.valid is False
-    assert df.errors
+    nose.tools.assert_false(df.valid)
+    nose.tools.assert_true(df.errors)
     nose.tools.eq_(len(df.errors), 1)
-    assert df.errors[0].find("invalid JSON code") != -1
+    nose.tools.assert_not_equal(df.errors[0].find("invalid JSON code"), -1)
 
 
 def test_load_valid_format():
 
     df = DataFormat(prefix, "user/single_integer/1")
-    assert df.valid, "\n  * %s" % "\n  * ".join(df.errors)
+    nose.tools.assert_true(df.valid, "\n  * %s" % "\n  * ".join(df.errors))
     nose.tools.eq_(len(df.errors), 0)
 
 
@@ -81,88 +79,92 @@ def test_load_valid_format():
 def test_fail_to_create_data_of_unknown_format():
 
     df = DataFormat(prefix, "user/unknown/1")
-    assert df.valid is False
-    assert df.type
+    nose.tools.assert_false(df.valid)
+    nose.tools.assert_true(df.type)
 
 
 def test_fail_to_load_format_with_several_invalid_types():
 
     df = DataFormat(prefix, "user/errors/1")
-    assert df.valid is False
+    nose.tools.assert_false(df.valid)
     nose.tools.eq_(len(df.errors), 1)
-    assert df.errors[0].find("is not valid under any of the given schemas") != -1
+    nose.tools.assert_not_equal(
+        df.errors[0].find("is not valid under any of the given schemas"), -1
+    )
 
 
 def test_load_valid_format_from_JSON_declaration():
 
     df = DataFormat(prefix, dict(value="int32"))
-    assert df.valid, "\n  * %s" % "\n  * ".join(df.errors)
-    assert df.name == "__unnamed_dataformat__"
+    nose.tools.assert_true(df.valid, "\n  * %s" % "\n  * ".join(df.errors))
+    nose.tools.eq_(df.name, "__unnamed_dataformat__")
 
 
 def test_load_versioned_format():
 
     df1 = DataFormat(prefix, "user/versioned/1")
-    assert df1.valid, "\n  * %s" % "\n  * ".join(df1.errors)
+    nose.tools.assert_true(df1.valid, "\n  * %s" % "\n  * ".join(df1.errors))
     nose.tools.eq_(df1.name, "user/versioned/1")
 
     df2 = DataFormat(prefix, "user/versioned/2")
-    assert df2.valid, "\n  * %s" % "\n  * ".join(df2.errors)
+    nose.tools.assert_true(df2.valid, "\n  * %s" % "\n  * ".join(df2.errors))
     nose.tools.eq_(df2.name, "user/versioned/2")
 
     ftype = df2.type
     instance = ftype(value=numpy.float32(32))
-    assert isinstance(instance.value, numpy.float32)
+    nose.tools.assert_true(isinstance(instance.value, numpy.float32))
 
 
 def test_no_description():
 
     df = DataFormat(prefix, "user/versioned/1")
-    assert df.valid, "\n  * %s" % "\n  * ".join(df.errors)
-    assert df.description is None
-    assert df.documentation is None
+    nose.tools.assert_true(df.valid, "\n  * %s" % "\n  * ".join(df.errors))
+    nose.tools.assert_is_none(df.description)
+    nose.tools.assert_is_none(df.documentation)
 
     description = "This is my descriptor"
     df.description = description
-    assert isinstance(df.description, six.string_types)
+    nose.tools.assert_true(isinstance(df.description, six.string_types))
     nose.tools.eq_(df.description, description)
 
 
 def test_with_description():
 
     df = DataFormat(prefix, "user/versioned/2")
-    assert df.valid, "\n  * %s" % "\n  * ".join(df.errors)
-    assert isinstance(df.description, six.string_types)
-    assert len(df.description) != 0
-    assert df.documentation is None
+    nose.tools.assert_true(df.valid, "\n  * %s" % "\n  * ".join(df.errors))
+    nose.tools.assert_true(isinstance(df.description, six.string_types))
+    nose.tools.assert_not_equal(len(df.description), 0)
+    nose.tools.assert_is_none(df.documentation)
 
 
 def test_description_does_not_affect_hash():
 
     df2 = DataFormat(prefix, "user/versioned/2")
-    assert df2.valid, "\n  * %s" % "\n  * ".join(df2.errors)
+    nose.tools.assert_true(df2.valid, "\n  * %s" % "\n  * ".join(df2.errors))
     df3 = DataFormat(prefix, "user/versioned/3")  # the same, but no description
-    assert df3.valid, "\n  * %s" % "\n  * ".join(df3.errors)
-    assert df2.hash() == df3.hash()
+    nose.tools.assert_true(df3.valid, "\n  * %s" % "\n  * ".join(df3.errors))
+    nose.tools.eq_(df2.hash(), df3.hash())
 
 
 def test_load_direct_recursion():
 
     df = DataFormat(prefix, "user/direct_recursion/1")
-    assert df.valid is False
-    assert df.errors
-    assert df.errors[0].find("recursion for") != -1
-    assert df.errors[0].find("user/direct_recursion/1") != -1
+    nose.tools.assert_false(df.valid)
+    nose.tools.assert_true(df.errors)
+    nose.tools.assert_not_equal(df.errors[0].find("recursion for"), -1)
+    nose.tools.assert_not_equal(df.errors[0].find("user/direct_recursion/1"), -1)
 
 
 def test_load_indirect_recursion():
 
     df = DataFormat(prefix, "user/indirect_recursion_top/1")
-    assert df.valid is False
-    assert df.errors
+    nose.tools.assert_false(df.valid)
+    nose.tools.assert_true(df.errors)
     nose.tools.eq_(len(df.errors), 1)
-    assert df.errors[0].find("is invalid") != -1
-    assert df.errors[0].find("user/indirect_recursion_bottom/1") != -1
+    nose.tools.assert_not_equal(df.errors[0].find("is invalid"), -1)
+    nose.tools.assert_not_equal(
+        df.errors[0].find("user/indirect_recursion_bottom/1"), -1
+    )
 
 
 @nose.tools.with_setup(teardown=cleanup)
@@ -170,10 +172,10 @@ def test_export():
 
     name = "user/composed/1"
     obj = DataFormat(prefix, name)
-    assert obj.valid, "\n  * %s" % "\n  * ".join(obj.errors)
+    nose.tools.assert_true(obj.valid, "\n  * %s" % "\n  * ".join(obj.errors))
 
     obj.export(tmp_prefix)
 
     # load from tmp_prefix and validates
     exported = DataFormat(tmp_prefix, name)
-    assert exported.valid, "\n  * %s" % "\n  * ".join(exported.errors)
+    nose.tools.assert_true(exported.valid, "\n  * %s" % "\n  * ".join(exported.errors))