Make config override rules explicit #415

Compare to:
https://github.com/ethereum/tests/blob/66ec8c662e411423ee3fdfe561476b4f6a0d0ea8/BlockchainTests/README.md
https://github.com/ethereum/tests/blob/f0c0319bbc8093abf02e7197df209e38197f0f8b/BlockchainTests/Homestead/README.md
https://github.com/ethereum/tests/blob/15f2351de2c7c6a31c6c1079759ee7fa40fdeae5/BlockchainTests/TestNetwork/README.md
https://github.com/ethereum/tests/blob/1626bd207eb0a89ae046f4b32a151351034da5d9/BlockchainTests/EIP150/README.md

Author: konradkonrad

ethereum/testutils.py

@@ -579,14 +579,13 @@ def fixture_to_bytes(value):
 
 def get_config_overrides(filename):
     override = {}
-    parts = filename.split(os.sep)
-    if 'Homestead' in parts:
+    if os.path.join('BlockchainTests', 'Homestead') in filename:
         override['HOMESTEAD_FORK_BLKNUM'] = 0
-    if 'TestNetwork' in parts:
+    elif os.path.join('BlockchainTests', 'TestNetwork') in filename:
         override['HOMESTEAD_FORK_BLKNUM'] = 5
         override['DAO_FORK_BLKNUM'] = 8
         override['ANTI_DOS_FORK_BLKNUM'] = 10
-    elif 'EIP150' in parts:
+    elif os.path.join('BlockchainTests', 'EIP150') in filename:
         override['HOMESTEAD_FORK_BLKNUM'] = 0
         override['ANTI_DOS_FORK_BLKNUM'] = 0
         override['DAO_FORK_BLKNUM'] = 2 ** 99  # not applicable