Merge bitcoin/bitcoin#25045: test: add coverage for invalid requests for blockfilterheaders (REST)

d1bfe5e test: add coverage for invalid requests for `blockfilterheaders` (brunoerg)

Pull request description:

  This PR adds test coverage for invalid requests (`Invalid hash` and `Unknown filtertype`) for `/blockfilterheaders` in REST functional test.

ACKs for top commit:
  jonatack:
    ACK d1bfe5e
  vincenzopalazzo:
    ACK bitcoin/bitcoin@d1bfe5e

Tree-SHA512: 9ab7efe7131296577c60642f95921799cf1dbae9c2aaea6752d2ac9f35a1bcc72b9d742a146c314f82fe1848190a80c88836ab78fc28773ed12e97fa327828e7

Author: MacroFake

test/functional/interface_rest.py

@@ -219,7 +219,7 @@ def run_test(self):
 
         self.generate(self.nodes[0], 1)  # generate block to not affect upcoming tests
 
-        self.log.info("Test the /block, /blockhashbyheight and /headers URIs")
+        self.log.info("Test the /block, /blockhashbyheight, /headers, and /blockfilterheaders URIs")
         bb_hash = self.nodes[0].getbestblockhash()
 
         # Check result if block does not exists
@@ -300,6 +300,12 @@ def run_test(self):
         assert_equal(first_filter_header, rpc_blockfilter['header'])
         assert_equal(json_obj['filter'], rpc_blockfilter['filter'])
 
+        # Test blockfilterheaders with an invalid hash and filtertype
+        resp = self.test_rest_request(f"/blockfilterheaders/{INVALID_PARAM}/{bb_hash}", ret_type=RetType.OBJ, status=400)
+        assert_equal(resp.read().decode('utf-8').rstrip(), f"Unknown filtertype {INVALID_PARAM}")
+        resp = self.test_rest_request(f"/blockfilterheaders/basic/{INVALID_PARAM}", ret_type=RetType.OBJ, status=400)
+        assert_equal(resp.read().decode('utf-8').rstrip(), f"Invalid hash: {INVALID_PARAM}")
+
         # Test number parsing
         for num in ['5a', '-5', '0', '2001', '99999999999999999999999999999999999']:
             assert_equal(