diff --git a/tests/backend/test_changefeed.py b/tests/backend/test_changefeed.py
index d9a8f45b..66ab57b4 100644
--- a/tests/backend/test_changefeed.py
+++ b/tests/backend/test_changefeed.py
@@ -3,10 +3,6 @@ from unittest.mock import Mock
 
 from multipipes import Pipe
 
-import bigchaindb
-from bigchaindb import Bigchain
-from bigchaindb.backend import connect
-
 
 @pytest.fixture
 def mock_changefeed_data():
@@ -26,6 +22,9 @@ def mock_changefeed_data():
 
 @pytest.fixture
 def mock_changefeed_connection(mock_changefeed_data):
+    import bigchaindb
+    from bigchaindb.backend import connect
+
     connection = connect(**bigchaindb.config['database'])
     connection.run = Mock(return_value=mock_changefeed_data)
     return connection
diff --git a/tests/backend/test_generics.py b/tests/backend/test_generics.py
index c7dffac5..4ec192d8 100644
--- a/tests/backend/test_generics.py
+++ b/tests/backend/test_generics.py
@@ -89,4 +89,4 @@ def test_init_database(mock_create_database, mock_create_tables,
     init_database(connection=conn, dbname='mickeymouse')
     mock_create_database.assert_called_once_with(conn, 'mickeymouse')
     mock_create_tables.assert_called_once_with(conn, 'mickeymouse')
-    mock_create_indexes.assert_called_once_with(conn, 'mickeymouse')
\ No newline at end of file
+    mock_create_indexes.assert_called_once_with(conn, 'mickeymouse')
diff --git a/tests/commands/test_commands.py b/tests/commands/test_commands.py
index a3fc3503..6ab3c26f 100644
--- a/tests/commands/test_commands.py
+++ b/tests/commands/test_commands.py
@@ -214,6 +214,7 @@ def test_run_configure_when_config_does_exist(monkeypatch,
                                               mock_generate_key_pair,
                                               mock_bigchaindb_backup_config):
     value = {}
+
     def mock_write_config(newconfig, filename=None):
         value['return'] = newconfig
 
@@ -236,7 +237,7 @@ def test_allow_temp_keypair_generates_one_on_the_fly(mock_gen_keypair,
     import bigchaindb
     from bigchaindb.commands.bigchain import run_start
 
-    bigchaindb.config['keypair'] = { 'private': None, 'public': None }
+    bigchaindb.config['keypair'] = {'private': None, 'public': None}
 
     args = Namespace(allow_temp_keypair=True, start_rethinkdb=False, config=None, yes=True)
     run_start(args)
diff --git a/tests/db/test_bigchain_api.py b/tests/db/test_bigchain_api.py
index 1d8cfd74..e294d490 100644
--- a/tests/db/test_bigchain_api.py
+++ b/tests/db/test_bigchain_api.py
@@ -578,7 +578,6 @@ class TestTransactionValidation(object):
 
         assert excinfo.value.args[0] == 'Only `CREATE` transactions can have null inputs'
 
-
     def test_non_create_input_not_found(self, b, user_pk, signed_transfer_tx):
         from bigchaindb.common.exceptions import TransactionDoesNotExist
         from bigchaindb.common.transaction import TransactionLink
@@ -729,7 +728,6 @@ class TestBlockValidation(object):
 
         assert excinfo.value.args[0] == 'owner_before `a` does not own the input `{}`'.format(valid_input)
 
-
     def test_invalid_signature(self, b):
         from bigchaindb.common.exceptions import InvalidSignature
         from bigchaindb.common import crypto
@@ -744,7 +742,6 @@ class TestBlockValidation(object):
         with pytest.raises(InvalidSignature):
             b.validate_block(block)
 
-
     def test_invalid_node_pubkey(self, b):
         from bigchaindb.common.exceptions import OperationError
         from bigchaindb.common import crypto
diff --git a/tests/pipelines/test_election.py b/tests/pipelines/test_election.py
index 28141dff..5cf6fc14 100644
--- a/tests/pipelines/test_election.py
+++ b/tests/pipelines/test_election.py
@@ -130,7 +130,6 @@ def test_check_requeue_transaction(b, user_pk):
     assert backlog_tx == tx1
 
 
-
 @patch.object(Pipeline, 'start')
 def test_start(mock_start):
     # TODO: `block.election` is just a wrapper around `block.create_pipeline`,
diff --git a/tests/pipelines/test_stale_monitor.py b/tests/pipelines/test_stale_monitor.py
index e964e28c..06ee5b5f 100644
--- a/tests/pipelines/test_stale_monitor.py
+++ b/tests/pipelines/test_stale_monitor.py
@@ -1,4 +1,3 @@
-import os
 import random
 from bigchaindb import Bigchain
 from bigchaindb.pipelines import stale
diff --git a/tests/test_core.py b/tests/test_core.py
index 5dfbc028..25be9649 100644
--- a/tests/test_core.py
+++ b/tests/test_core.py
@@ -1,5 +1,3 @@
-from rethinkdb.ast import RqlQuery
-
 import pytest
 
 
diff --git a/tests/test_processes.py b/tests/test_processes.py
index 7013dc03..bd69d52c 100644
--- a/tests/test_processes.py
+++ b/tests/test_processes.py
@@ -20,4 +20,3 @@ def test_processes_start(mock_vote, mock_block, mock_election, mock_stale,
     mock_election.assert_called_with()
     mock_stale.assert_called_with()
     mock_process.assert_called_with()
-