diff --git a/tests/device_tests/signtx.py b/tests/device_tests/signtx.py
index be75084ab..1b4da1ce0 100644
--- a/tests/device_tests/signtx.py
+++ b/tests/device_tests/signtx.py
@@ -3,46 +3,46 @@ from trezorlib import messages
 T = messages.RequestType
 
 
-def request_input(n, tx_hash=None):
+def request_input(n: int, tx_hash: bytes = None) -> messages.TxRequest:
     return messages.TxRequest(
         request_type=T.TXINPUT,
         details=messages.TxRequestDetailsType(request_index=n, tx_hash=tx_hash),
     )
 
 
-def request_output(n, tx_hash=None):
+def request_output(n: int, tx_hash: bytes = None) -> messages.TxRequest:
     return messages.TxRequest(
         request_type=T.TXOUTPUT,
         details=messages.TxRequestDetailsType(request_index=n, tx_hash=tx_hash),
     )
 
 
-def request_orig_input(n, tx_hash):
+def request_orig_input(n: int, tx_hash: bytes) -> messages.TxRequest:
     return messages.TxRequest(
         request_type=T.TXORIGINPUT,
         details=messages.TxRequestDetailsType(request_index=n, tx_hash=tx_hash),
     )
 
 
-def request_orig_output(n, tx_hash):
+def request_orig_output(n: int, tx_hash: bytes) -> messages.TxRequest:
     return messages.TxRequest(
         request_type=T.TXORIGOUTPUT,
         details=messages.TxRequestDetailsType(request_index=n, tx_hash=tx_hash),
     )
 
 
-def request_meta(tx_hash):
+def request_meta(tx_hash: bytes) -> messages.TxRequest:
     return messages.TxRequest(
         request_type=T.TXMETA,
         details=messages.TxRequestDetailsType(tx_hash=tx_hash),
     )
 
 
-def request_finished():
+def request_finished() -> messages.TxRequest:
     return messages.TxRequest(request_type=T.TXFINISHED)
 
 
-def request_extra_data(ofs, len, tx_hash):
+def request_extra_data(ofs: int, len: int, tx_hash: bytes) -> messages.TxRequest:
     return messages.TxRequest(
         request_type=T.TXEXTRADATA,
         details=messages.TxRequestDetailsType(
diff --git a/tests/tx_cache.py b/tests/tx_cache.py
index a802ffb38..f43a05b82 100755
--- a/tests/tx_cache.py
+++ b/tests/tx_cache.py
@@ -52,10 +52,10 @@ BLOCKBOOKS = _get_blockbooks()
 
 
 class TxCache:
-    def __init__(self, coin_name):
+    def __init__(self, coin_name: str) -> None:
         self.slug = coin_name.lower().replace(" ", "_")
 
-    def get_tx(self, txhash):
+    def get_tx(self, txhash: str) -> messages.TransactionType:
         try:
             (CACHE_PATH / self.slug).mkdir()
         except Exception:
@@ -71,10 +71,10 @@ class TxCache:
         txdict = json.loads(cache_file.read_text())
         return protobuf.dict_to_proto(messages.TransactionType, txdict)
 
-    def __getitem__(self, key):
+    def __getitem__(self, key: bytes) -> messages.TransactionType:
         return self.get_tx(key.hex())
 
-    def __contains__(self, key):
+    def __contains__(self, key: bytes) -> bool:
         try:
             self.get_tx(key.hex())
             return True