Merge bitcoin/bitcoin#26730: test: add coverage for purpose arg in listlabels

c467cff test: add coverage for `purpose` arg in `listlabels` (brunoerg)

Pull request description:

  This PR adds test coverage for `listlabels` command when specifying the `purpose` (send and receive).

  https://github.com/bitcoin/bitcoin/blob/dcdfd72861c09a7945b9facc3726177a2d06fa64/src/wallet/rpc/addresses.cpp#L698-L704

ACKs for top commit:
  kristapsk:
    ACK c467cff

Tree-SHA512: 7e7143c1264692f7b22952e7c70dbe9ed3f5dcd2e3b69962a47be9f9c21b3f4a9089ca87962fbc8ff9116e7d2dbeb7f36d6a132c9ac13724a255cfe1b32373a8

Author: MarcoFalke

test/functional/wallet_labels.py

@@ -23,7 +23,7 @@ def add_options(self, parser):
 
     def set_test_params(self):
         self.setup_clean_chain = True
-        self.num_nodes = 1
+        self.num_nodes = 2
 
     def skip_test_if_missing_module(self):
         self.skip_if_no_wallet()
@@ -121,8 +121,14 @@ def run_test(self):
             label.add_receive_address(address)
             label.verify(node)
 
+        # Check listlabels when passing 'purpose'
+        node2_addr = self.nodes[1].getnewaddress()
+        node.setlabel(node2_addr, "node2_addr")
+        assert_equal(node.listlabels(purpose="send"), ["node2_addr"])
+        assert_equal(node.listlabels(purpose="receive"), sorted(['coinbase'] + [label.name for label in labels]))
+
         # Check all labels are returned by listlabels.
-        assert_equal(node.listlabels(), sorted(['coinbase'] + [label.name for label in labels]))
+        assert_equal(node.listlabels(), sorted(['coinbase'] + [label.name for label in labels] + ["node2_addr"]))
 
         # Send a transaction to each label.
         for label in labels: