configuration should be specified explicitly

tests/test_calib.py

@@ -1,5 +1,6 @@
 from amodem import calib
 from amodem import config
+config = config.fastest()
 
 from io import BytesIO
 

tests/test_dsp.py

@@ -2,8 +2,9 @@ import numpy as np
 from numpy.linalg import norm
 
 from amodem import dsp
-from amodem import config
 from amodem import sampling
+from amodem import config
+config = config.fastest()
 
 import random
 import itertools

tests/test_equalizer.py

@@ -3,9 +3,9 @@ from numpy.random import RandomState
 import numpy as np
 
 from amodem import dsp
-from amodem import config
 from amodem import equalizer
-
+from amodem import config
+config = config.fastest()
 
 def assert_approx(x, y, e=1e-12):
     assert norm(x - y) < e * norm(x)

tests/test_recv.py

@@ -1,10 +1,11 @@
 import numpy as np
 
-from amodem import config
 from amodem import dsp
 from amodem import recv
 from amodem import train
 from amodem import sampling
+from amodem import config
+config = config.fastest()
 
 
 def test_detect():

tests/test_whole.py

@@ -9,6 +9,7 @@ from amodem import common
 from amodem import dsp
 from amodem import sampling
 from amodem import config
+config = config.fastest()
 
 import logging
 logging.basicConfig(level=logging.DEBUG,