diff --git a/bip-0089/reference.py b/bip-0089/reference.py
index f81d5359a2..3ede724e90 100644
--- a/bip-0089/reference.py
+++ b/bip-0089/reference.py
@@ -7,9 +7,8 @@
 from typing import Dict, Mapping, Optional, Sequence, Tuple, NewType, NamedTuple, List, Callable, Any, cast
 import hashlib
 import json
-import os
+from pathlib import Path
 import secrets
-import sys
 
 from bip32 import (
     CURVE_N,
@@ -280,7 +279,7 @@ def build_session_ctx(obj):
     return (pk, a, e, R, tweaks, is_xonly)
 
 def test_blind_nonce_gen_vectors():
-    with open(os.path.join(sys.path[0], 'vectors', 'blind_nonce_gen_vectors.json')) as f:
+    with open(Path(__file__).parent / 'vectors' / 'blind_nonce_gen_vectors.json') as f:
         tv = json.load(f)
 
     for tc in tv["test_cases"]:
@@ -311,7 +310,7 @@ def get_bytes_maybe(key) -> Optional[bytes]:
         assert len(expected_blindpubnonce) == 33
 
 def test_blind_challenge_gen_vectors():
-    with open(os.path.join(sys.path[0], 'vectors', 'blind_challenge_gen_vectors.json')) as f:
+    with open(Path(__file__).parent / 'vectors' / 'blind_challenge_gen_vectors.json') as f:
         tv = json.load(f)
 
     # ---------- Valid cases ----------
@@ -388,7 +387,7 @@ def test_blind_challenge_gen_vectors():
         assert raised, "Expected an exception but none was raised"
 
 def test_blind_sign_and_verify_vectors():
-    with open(os.path.join(sys.path[0], 'vectors', 'blind_sign_and_verify_vectors.json')) as f:
+    with open(Path(__file__).parent / 'vectors' / 'blind_sign_and_verify_vectors.json') as f:
         tv = json.load(f)
 
     # ------------------ Valid ------------------
@@ -479,7 +478,7 @@ def try_again():
         assert_raises(exception, lambda: verify_blind_signature(pk, blindpubnonce, blindchallenge, blindsignature, pk_parity, nonce_parity), except_fn)
 
 def test_unblind_signature_vectors():
-    with open(os.path.join(sys.path[0], 'vectors', 'unblind_signature_vectors.json')) as f:
+    with open(Path(__file__).parent / 'vectors' / 'unblind_signature_vectors.json') as f:
         tv = json.load(f)
 
     # ---------- Valid ----------
@@ -619,7 +618,7 @@ def delegator_sign(
     return signature
 
 def test_compute_tweak_vectors() -> None:
-    with open(os.path.join(sys.path[0], 'vectors', 'compute_bip32_tweak_vectors.json')) as f:
+    with open(Path(__file__).parent / 'vectors' / 'compute_bip32_tweak_vectors.json') as f:
         data = json.load(f)
 
     default_xpub_data = data.get("xpub")
@@ -675,7 +674,7 @@ def test_compute_tweak_vectors() -> None:
             raise AssertionError("expected failure but case succeeded")
 
 def test_delegator_sign_vectors() -> None:
-    with open(os.path.join(sys.path[0], 'vectors', 'delegator_sign_vectors.json')) as f:
+    with open(Path(__file__).parent / 'vectors' / 'delegator_sign_vectors.json') as f:
         data = json.load(f)
 
     for case in data.get("test_cases", []):
@@ -706,7 +705,7 @@ def test_delegator_sign_vectors() -> None:
 
 
 def test_input_verification_vectors() -> None:
-    with open(os.path.join(sys.path[0], 'vectors', 'input_verification_vectors.json')) as f:
+    with open(Path(__file__).parent / 'vectors' / 'input_verification_vectors.json') as f:
         data = json.load(f)
 
 
@@ -729,7 +728,7 @@ def test_input_verification_vectors() -> None:
             )
 
 def test_change_output_verification_vectors() -> None:
-    with open(os.path.join(sys.path[0], 'vectors', 'change_output_verification_vectors.json')) as f:
+    with open(Path(__file__).parent / 'vectors' / 'change_output_verification_vectors.json') as f:
         data = json.load(f)
 
     for case in data.get("test_cases", []):
diff --git a/bip-0327/gen_vectors_helper.py b/bip-0327/gen_vectors_helper.py
index 03c2dbb2ac..ebd245f93a 100644
--- a/bip-0327/gen_vectors_helper.py
+++ b/bip-0327/gen_vectors_helper.py
@@ -1,3 +1,5 @@
+from pathlib import Path
+
 from reference import *
 
 def gen_key_agg_vectors():
@@ -16,7 +18,7 @@ def gen_key_agg_vectors():
     print("  tweak: ", tweak.hex().upper())
 
 def check_sign_verify_vectors():
-    with open(os.path.join(sys.path[0], 'vectors', 'sign_verify_vectors.json')) as f:
+    with open(Path(__file__).parent / 'vectors' / 'sign_verify_vectors.json') as f:
         test_data = json.load(f)
     X = fromhex_all(test_data["pubkeys"])
     pnonce = fromhex_all(test_data["pnonces"])
@@ -44,7 +46,7 @@ def check_sign_verify_vectors():
            assert has_even_y(Q) and has_even_y(R)
 
 def check_tweak_vectors():
-    with open(os.path.join(sys.path[0], 'vectors', 'tweak_vectors.json')) as f:
+    with open(Path(__file__).parent / 'vectors' / 'tweak_vectors.json') as f:
         test_data = json.load(f)
 
     X = fromhex_all(test_data["pubkeys"])
diff --git a/bip-0327/reference.py b/bip-0327/reference.py
index 5b8d114f65..a7d72481a6 100644
--- a/bip-0327/reference.py
+++ b/bip-0327/reference.py
@@ -462,8 +462,7 @@ def partial_sig_agg(psigs: List[bytes], session_ctx: SessionContext) -> bytes:
 #
 
 import json
-import os
-import sys
+from pathlib import Path
 
 def fromhex_all(l):
     return [bytes.fromhex(l_i) for l_i in l]
@@ -497,7 +496,7 @@ def get_error_details(test_case):
     return exception, except_fn
 
 def test_key_sort_vectors() -> None:
-    with open(os.path.join(sys.path[0], 'vectors', 'key_sort_vectors.json')) as f:
+    with open(Path(__file__).parent / 'vectors' / 'key_sort_vectors.json') as f:
         test_data = json.load(f)
 
     X = fromhex_all(test_data["pubkeys"])
@@ -506,7 +505,7 @@ def test_key_sort_vectors() -> None:
     assert key_sort(X) == X_sorted
 
 def test_key_agg_vectors() -> None:
-    with open(os.path.join(sys.path[0], 'vectors', 'key_agg_vectors.json')) as f:
+    with open(Path(__file__).parent / 'vectors' / 'key_agg_vectors.json') as f:
         test_data = json.load(f)
 
     X = fromhex_all(test_data["pubkeys"])
@@ -530,7 +529,7 @@ def test_key_agg_vectors() -> None:
         assert_raises(exception, lambda: key_agg_and_tweak(pubkeys, tweaks, is_xonly), except_fn)
 
 def test_nonce_gen_vectors() -> None:
-    with open(os.path.join(sys.path[0], 'vectors', 'nonce_gen_vectors.json')) as f:
+    with open(Path(__file__).parent / 'vectors' / 'nonce_gen_vectors.json') as f:
         test_data = json.load(f)
 
     for test_case in test_data["test_cases"]:
@@ -557,7 +556,7 @@ def get_value_maybe(key) -> Optional[bytes]:
         assert nonce_gen_internal(rand_, sk, pk, aggpk, msg, extra_in) == (expected_secnonce, expected_pubnonce)
 
 def test_nonce_agg_vectors() -> None:
-    with open(os.path.join(sys.path[0], 'vectors', 'nonce_agg_vectors.json')) as f:
+    with open(Path(__file__).parent / 'vectors' / 'nonce_agg_vectors.json') as f:
         test_data = json.load(f)
 
     pnonce = fromhex_all(test_data["pnonces"])
@@ -575,7 +574,7 @@ def test_nonce_agg_vectors() -> None:
         assert_raises(exception, lambda: nonce_agg(pubnonces), except_fn)
 
 def test_sign_verify_vectors() -> None:
-    with open(os.path.join(sys.path[0], 'vectors', 'sign_verify_vectors.json')) as f:
+    with open(Path(__file__).parent / 'vectors' / 'sign_verify_vectors.json') as f:
         test_data = json.load(f)
 
     sk = bytes.fromhex(test_data["sk"])
@@ -658,7 +657,7 @@ def test_sign_verify_vectors() -> None:
         assert_raises(exception, lambda: partial_sig_verify(sig, pubnonces, pubkeys, [], [], msg, signer_index), except_fn)
 
 def test_tweak_vectors() -> None:
-    with open(os.path.join(sys.path[0], 'vectors', 'tweak_vectors.json')) as f:
+    with open(Path(__file__).parent / 'vectors' / 'tweak_vectors.json') as f:
         test_data = json.load(f)
 
     sk = bytes.fromhex(test_data["sk"])
@@ -715,7 +714,7 @@ def test_tweak_vectors() -> None:
         assert_raises(exception, lambda: sign(secnonce, sk, session_ctx), except_fn)
 
 def test_det_sign_vectors() -> None:
-    with open(os.path.join(sys.path[0], 'vectors', 'det_sign_vectors.json')) as f:
+    with open(Path(__file__).parent / 'vectors' / 'det_sign_vectors.json') as f:
         test_data = json.load(f)
 
     sk = bytes.fromhex(test_data["sk"])
@@ -762,7 +761,7 @@ def test_det_sign_vectors() -> None:
         assert_raises(exception, try_fn, except_fn)
 
 def test_sig_agg_vectors() -> None:
-    with open(os.path.join(sys.path[0], 'vectors', 'sig_agg_vectors.json')) as f:
+    with open(Path(__file__).parent / 'vectors' / 'sig_agg_vectors.json') as f:
         test_data = json.load(f)
 
     X = fromhex_all(test_data["pubkeys"])
diff --git a/bip-0328/reference.py b/bip-0328/reference.py
index d7e493e2ea..f114250815 100644
--- a/bip-0328/reference.py
+++ b/bip-0328/reference.py
@@ -1,8 +1,7 @@
 #! /usr/bin/env python3
 
 import json
-import os
-import sys
+from pathlib import Path
 
 from _base58 import xpub_to_pub_hex
 from _bip327 import cbytes, key_agg
@@ -14,7 +13,7 @@ def aggregate_to_xpub(aggregate: bytes) -> ExtendedKey:
     return ExtendedKey(ExtendedKey.MAINNET_PUBLIC, 0, b"\x00\x00\x00\x00", 0, CHAINCODE, None, aggregate)
 
 def test_aggregate_to_xpub():
-    with open(os.path.join(sys.path[0], "vectors.json"), "r") as f:
+    with open(Path(__file__).parent / "vectors.json", "r") as f:
         test_data = json.load(f)
 
     for test_case in test_data:
diff --git a/bip-0340/reference.py b/bip-0340/reference.py
index bf8f16203a..f6d8af7bf5 100644
--- a/bip-0340/reference.py
+++ b/bip-0340/reference.py
@@ -140,12 +140,11 @@ def schnorr_verify(msg: bytes, pubkey: bytes, sig: bytes) -> bool:
 # The following code is only used to verify the test vectors.
 #
 import csv
-import os
-import sys
+from pathlib import Path
 
 def test_vectors() -> bool:
     all_passed = True
-    with open(os.path.join(sys.path[0], 'test-vectors.csv'), newline='') as csvfile:
+    with open(Path(__file__).parent / 'test-vectors.csv', newline='') as csvfile:
         reader = csv.reader(csvfile)
         reader.__next__()
         for row in reader: