Merge bitcoin#27422: test: add coverage to rpc_scantxoutset.py

7e3d4f8 test: add coverage to ensure the first arg of scantxoutset is needed (ismaelsadeeq)

Pull request description:

  Include a test that checks whether the first argument of scantxoutset RPC call "start" is required.
  The rpc call should fail if the "start" argument is not provided.

ACKs for top commit:
  MarcoFalke:
    lgtm ACK 7e3d4f8

Tree-SHA512: 6a456af9f3ccd5437be2edcd61936eb9f9c21ab926a6056c2c11b6b5121d1caca4e1f2ffd09015f9414af152c635a20e1da041eefdef980afbe8a0e8ccce07bd

test/functional/rpc_scantxoutset.py

@@ -120,6 +120,9 @@ def run_test(self):
         assert_equal(self.nodes[0].scantxoutset("status"), None)
         assert_equal(self.nodes[0].scantxoutset("abort"), False)
 
+        # check that first arg is needed
+        assert_raises_rpc_error(-1, "scantxoutset \"action\" ( [scanobjects,...] )", self.nodes[0].scantxoutset)
+
         # Check that second arg is needed for start
         assert_raises_rpc_error(-1, "scanobjects argument is required for the start action", self.nodes[0].scantxoutset, "start")