use same name for function to load test data

The test data loading function was previously sometimes plural and
sometimes singular. This makes it always plural, because each file might
have multiple different vectors of test data.

Author: kanzure

bitcoin/tests/test_base58.py

@@ -20,14 +20,14 @@
 from bitcoin.base58 import *
 
 
-def load_test_vector(name):
+def load_test_vectors(name):
     with open(os.path.dirname(__file__) + '/data/' + name, 'r') as fd:
         for testcase in json.load(fd):
             yield testcase
 
 class Test_base58(unittest.TestCase):
     def test_encode_decode(self):
-        for exp_bin, exp_base58 in load_test_vector('base58_encode_decode.json'):
+        for exp_bin, exp_base58 in load_test_vectors('base58_encode_decode.json'):
             exp_bin = unhexlify(exp_bin.encode('utf8'))
 
             act_base58 = encode(exp_bin)