test: Remove unused, undocumented and misleading CScript.__add__

test/functional/feature_rbf.py

@@ -10,7 +10,7 @@ from test_framework.messages import COIN, COutPoint, CTransaction, CTxIn, CTxOut
 from test_framework.script import CScript, OP_DROP
 from test_framework.test_framework import BitcoinTestFramework
 from test_framework.util import assert_equal, assert_raises_rpc_error, satoshi_round
-from test_framework.script_util import DUMMY_P2WPKH_SCRIPT
+from test_framework.script_util import DUMMY_P2WPKH_SCRIPT, DUMMY_2_P2WPKH_SCRIPT
 
 MAX_REPLACEMENT_LIMIT = 100
 
@@ -142,7 +142,7 @@ class ReplaceByFeeTest(BitcoinTestFramework):
         # Should fail because we haven't changed the fee
         tx1b = CTransaction()
         tx1b.vin = [CTxIn(tx0_outpoint, nSequence=0)]
-        tx1b.vout = [CTxOut(1 * COIN, DUMMY_P2WPKH_SCRIPT + b'a')]
+        tx1b.vout = [CTxOut(1 * COIN, DUMMY_2_P2WPKH_SCRIPT)]
         tx1b_hex = txToHex(tx1b)
 
         # This will raise an exception due to insufficient fee

test/functional/test_framework/script.py

@@ -449,15 +449,8 @@ class CScript(bytes):
         return other
 
     def __add__(self, other):
-        # Do the coercion outside of the try block so that errors in it are
-        # noticed.
-        other = self.__coerce_instance(other)
-
-        try:
-            # bytes.__add__ always returns bytes instances unfortunately
-            return CScript(super(CScript, self).__add__(other))
-        except TypeError:
-            raise TypeError('Can not add a %r instance to a CScript' % other.__class__)
+        # add makes no sense for a CScript()
+        raise NotImplementedError
 
     def join(self, iterable):
         # join makes no sense for a CScript()

test/functional/test_framework/script_util.py

@@ -23,3 +23,4 @@ from test_framework.script import CScript
 # scriptPubKeys are needed, to guarantee that the minimum transaction size is
 # met.
 DUMMY_P2WPKH_SCRIPT = CScript([b'a' * 21])
+DUMMY_2_P2WPKH_SCRIPT = CScript([b'b' * 21])