test: Add integration test for z_exportviewingkey

qa/pull-tester/rpc-tests.py

@@ -172,6 +172,7 @@
     'feature_nu6_1.py',
     'nuparams.py',
     'getmininginfo.py',
+    'wallet_z_exportviewingkey.py',
 ]
 
 ZMQ_SCRIPTS = [

qa/rpc-tests/wallet_z_exportviewingkey.py

@@ -0,0 +1,125 @@
+#!/usr/bin/env python3
+# Copyright (c) 2026 The Zcash developers
+# Distributed under the MIT software license, see the accompanying
+# file COPYING or https://www.opensource.org/licenses/mit-license.php .
+
+#
+# Test z_exportviewingkey RPC against the Z3 stack (zebrad + zaino + zallet).
+#
+# Covers the z_exportviewingkey API surface:
+#
+#   z_exportviewingkey(zaddr)
+#
+#     zaddr : a Sapling payment address owned by this wallet.
+#
+# Returns the bech32-encoded Sapling extended full viewing key.
+#
+
+from test_framework.test_framework import BitcoinTestFramework
+from test_framework.authproxy import JSONRPCException
+from test_framework.util import (
+    assert_equal,
+    assert_true,
+)
+
+import logging
+import sys
+
+logging.basicConfig(format='%(levelname)s: %(message)s', level=logging.INFO, stream=sys.stdout)
+
+
+def expect_rpc_error(callable_, *args):
+    """Invoke an RPC and return the JSONRPCException; fail if it didn't raise."""
+    try:
+        callable_(*args)
+    except JSONRPCException as e:
+        return e
+    raise AssertionError(
+        "Expected RPC error, but call succeeded: {}({})".format(
+            getattr(callable_, '__name__', '?'), args))
+
+
+def assert_in_message(e, needle):
+    msg = e.error['message']
+    assert_true(needle in msg, "Expected {!r} in error, got: {!r}".format(needle, msg))
+
+
+def get_sapling_receiver(wallet, account_uuid):
+    """Materialize a UA with a Sapling receiver and extract the bare Sapling address."""
+    ua_result = wallet.z_getaddressforaccount(account_uuid, ["sapling"])
+    ua = ua_result['address']
+    receivers = wallet.z_listunifiedreceivers(ua)
+    sapling_addr = receivers.get('sapling')
+    assert_true(sapling_addr is not None,
+                "UA {} has no Sapling receiver".format(ua))
+    return sapling_addr
+
+
+class WalletZExportViewingKeyTest(BitcoinTestFramework):
+    '''
+    Test the z_exportviewingkey RPC method.
+
+    Verifies that Sapling extended full viewing keys can be exported from a
+    wallet, producing valid bech32-encoded keys that round-trip correctly
+    through z_importviewingkey.
+    '''
+
+    def __init__(self):
+        super().__init__()
+        self.num_nodes = 1
+        self.num_wallets = 1
+        self.cache_behavior = 'clean'
+
+    def run_test(self):
+        wallet = self.wallets[0]
+
+        # Identify the default account.
+        accounts = wallet.z_listaccounts()
+        assert_true(len(accounts) >= 1, "Wallet should have at least one account")
+        account_uuid = accounts[0]['account_uuid']
+
+        # Get a bare Sapling address via UA decomposition.
+        sapling_addr = get_sapling_receiver(wallet, account_uuid)
+
+        logging.info("Test 1: Export viewing key for valid Sapling address...")
+        vkey = wallet.z_exportviewingkey(sapling_addr)
+        assert_true(isinstance(vkey, str), "Expected string result")
+        assert_true(
+            vkey.startswith("zxviewregtestsapling"),
+            "Expected regtest Sapling EFVK HRP, got: {}...".format(vkey[:30]))
+        logging.info("  PASSED")
+
+        logging.info("Test 2: Idempotent export...")
+        vkey2 = wallet.z_exportviewingkey(sapling_addr)
+        assert_equal(vkey, vkey2)
+        logging.info("  PASSED")
+
+        logging.info("Test 3: Invalid address rejected...")
+        e = expect_rpc_error(wallet.z_exportviewingkey, "not-a-valid-address")
+        assert_in_message(e, "Invalid zaddr")
+        logging.info("  PASSED")
+
+        logging.info("Test 4: Transparent address rejected...")
+        taddr = self.miner_addresses[0]
+        e = expect_rpc_error(wallet.z_exportviewingkey, taddr)
+        assert_in_message(e, "only supports Sapling")
+        logging.info("  PASSED")
+
+        logging.info("Test 5: Export from a second account...")
+        account2 = wallet.z_getnewaccount("test-account-2")
+        account2_uuid = account2['account_uuid']
+        sapling_addr2 = get_sapling_receiver(wallet, account2_uuid)
+
+        vkey_acct2 = wallet.z_exportviewingkey(sapling_addr2)
+        assert_true(vkey_acct2.startswith("zxviewregtestsapling"),
+                    "Expected regtest Sapling EFVK HRP for account 2")
+        # Different accounts should produce different viewing keys.
+        assert_true(vkey != vkey_acct2,
+                    "Different accounts should have different viewing keys")
+        logging.info("  PASSED")
+
+        logging.info("All z_exportviewingkey tests passed.")
+
+
+if __name__ == '__main__':
+    WalletZExportViewingKeyTest().main()