Fix BTC segwit regex to accept testnet (tb) prefix

The bech32/segwit branch guard routes both `bc` (mainnet) and `tb` (testnet)
HRPs into the regex, but the regex accepted `(bc|tc)`. `tc` is not a valid
Bitcoin HRP (mainnet is `bc`, testnet is `tb`), and since the guard never
lets a `tc`-prefixed value reach the regex, that alternative was dead code.
As a result every valid testnet segwit address was rejected.

Change the regex alternative to `(bc|tb)` and add a testnet address test.

Author: uttam12331

src/validators/crypto_addresses/btc_address.py

@@ -50,7 +50,7 @@ def btc_address(value: str, /):
 
     return (
         # segwit pattern
-        re.compile(r"^(bc|tc)[0-3][02-9ac-hj-np-z]{14,74}$").match(value)
+        re.compile(r"^(bc|tb)[0-3][02-9ac-hj-np-z]{14,74}$").match(value)
         if value[:2] in ("bc", "tb")
         else _validate_old_btc_address(value)
     )

tests/crypto_addresses/test_btc_address.py

@@ -17,6 +17,8 @@
         # Bech32/segwit type
         "bc1qar0srrr7xfkvy5l643lydnw9re59gtzzwf5mdq",
         "bc1qc7slrfxkknqcq2jevvvkdgvrt8080852dfjewde450xdlk4ugp7szw5tk9",
+        # Bech32/segwit type, testnet (tb) HRP
+        "tb1qw508d6qejxtdg4y5r3zarvary0c5xw7kxpjzsx",
     ],
 )
 def test_returns_true_on_valid_btc_address(value: str):