Merge bitcoin/bitcoin#33020: test: delete commented-out tests and add a test case in wallet_signer

da318fe test: delete commented out tests (naiyoma)
6d80e99 test: external signer returns invalid JSON response (naiyoma)

Pull request description:

  I noticed that some test cases had been commented out in wallet_signer.py.
  This PR uncomments and modifies some of those test cases so that they can pass.

  bitcoin/bitcoin@dac74c6 -> deleting this assertion since multiple signers is being tested here https://github.com/bitcoin/bitcoin/blob/master/test/functional/wallet_signer.py#L273

  bitcoin/bitcoin@1707c90 test when  an external signer returns malformed or invalid JSON, which would trigger this error:
  → https://github.com/bitcoin/bitcoin/blob/master/src/common/run_command.cpp#L42

  bitcoin/bitcoin@b961568 test  importdescriptors with external signer

ACKs for top commit:
  Sjors:
    ACK da318fe
  achow101:
    ACK da318fe
  theStack:
    ACK da318fe

Tree-SHA512: 6416f83abed1923d72a8a83c5937e8f732e02b5396b5bd3fe868d28e8f3cb2bf55f3bcbc2ec8219302b55045fa1d9e7ce119b4e8bdea2df2103fede9f109eacf

Author: achow101

test/functional/wallet_signer.py

@@ -78,14 +78,12 @@ def test_valid_signer(self):
         assert_equal(not_hww.getwalletinfo()["external_signer"], False)
         assert_raises_rpc_error(-8, "Wallet flag is immutable: external_signer", not_hww.setwalletflag, "external_signer", True)
 
-        # assert_raises_rpc_error(-4, "Multiple signers found, please specify which to use", wallet_name='not_hww', disable_private_keys=True, external_signer=True)
 
-        # TODO: Handle error thrown by script
-        # self.set_mock_result(self.nodes[1], "2")
-        # assert_raises_rpc_error(-1, 'Unable to parse JSON',
-        #     self.nodes[1].createwallet, wallet_name='not_hww2', disable_private_keys=True, external_signer=False
-        # )
-        # self.clear_mock_result(self.nodes[1])
+        self.set_mock_result(self.nodes[1], '0 {"invalid json"}')
+        assert_raises_rpc_error(-1, 'Unable to parse JSON',
+            self.nodes[1].createwallet, wallet_name='hww2', disable_private_keys=True, external_signer=True
+        )
+        self.clear_mock_result(self.nodes[1])
 
         assert_equal(hww.getwalletinfo()["keypoolsize"], 40)
 
@@ -168,31 +166,6 @@ def test_valid_signer(self):
         mock_tx = mock_psbt_signed["hex"]
         assert mock_wallet.testmempoolaccept([mock_tx])[0]["allowed"]
 
-        # # Create a new wallet and populate with specific public keys, in order
-        # # to work with the mock signed PSBT.
-        # self.nodes[1].createwallet(wallet_name="hww4", disable_private_keys=True, external_signer=True)
-        # hww4 = self.nodes[1].get_wallet_rpc("hww4")
-        #
-        # descriptors = [{
-        #     "desc": "wpkh([00000001/84h/1h/0']tpubD6NzVbkrYhZ4WaWSyoBvQwbpLkojyoTZPRsgXELWz3Popb3qkjcJyJUGLnL4qHHoQvao8ESaAstxYSnhyswJ76uZPStJRJCTKvosUCJZL5B/0/*)#x30uthjs",
-        #     "timestamp": "now",
-        #     "range": [0, 1],
-        #     "internal": False,
-        #     "watchonly": True,
-        #     "active": True
-        # },
-        # {
-        #     "desc": "wpkh([00000001/84h/1h/0']tpubD6NzVbkrYhZ4WaWSyoBvQwbpLkojyoTZPRsgXELWz3Popb3qkjcJyJUGLnL4qHHoQvao8ESaAstxYSnhyswJ76uZPStJRJCTKvosUCJZL5B/1/*)#h92akzzg",
-        #     "timestamp": "now",
-        #     "range": [0, 0],
-        #     "internal": True,
-        #     "watchonly": True,
-        #     "active": True
-        # }]
-
-        # result = hww4.importdescriptors(descriptors)
-        # assert_equal(result[0], {'success': True})
-        # assert_equal(result[1], {'success': True})
         assert_equal(hww.getwalletinfo()["txcount"], 1)
 
         assert hww.testmempoolaccept([mock_tx])[0]["allowed"]
@@ -232,12 +205,6 @@ def test_valid_signer(self):
         assert_greater_than(res["fee"], res["origfee"])
         assert_equal(res["errors"], [])
 
-        # # Handle error thrown by script
-        # self.set_mock_result(self.nodes[4], "2")
-        # assert_raises_rpc_error(-1, 'Unable to parse JSON',
-        #     hww4.signerprocesspsbt, psbt_orig, "00000001"
-        # )
-        # self.clear_mock_result(self.nodes[4])
 
     def test_disconnected_signer(self):
         self.log.info('Test disconnected external signer')