Throw error if invalid parameters passed to getnetworkhashps RPC endpoint

Github-Pull: #28554
Rebased-From: 9ac114e5cd

test/functional/rpc_blockchain.py

@@ -436,7 +436,6 @@ class BlockchainTest(BitcoinTestFramework):
 
     def _test_getnetworkhashps(self):
         self.log.info("Test getnetworkhashps")
-        hashes_per_second = self.nodes[0].getnetworkhashps()
         assert_raises_rpc_error(
             -3,
             textwrap.dedent("""
@@ -448,7 +447,33 @@ class BlockchainTest(BitcoinTestFramework):
             """).strip(),
             lambda: self.nodes[0].getnetworkhashps("a", []),
         )
+        assert_raises_rpc_error(
+            -8,
+            "Block does not exist at specified height",
+            lambda: self.nodes[0].getnetworkhashps(100, self.nodes[0].getblockcount() + 1),
+        )
+        assert_raises_rpc_error(
+            -8,
+            "Block does not exist at specified height",
+            lambda: self.nodes[0].getnetworkhashps(100, -10),
+        )
+        assert_raises_rpc_error(
+            -8,
+            "Invalid nblocks. Must be a positive number or -1.",
+            lambda: self.nodes[0].getnetworkhashps(-100),
+        )
+        assert_raises_rpc_error(
+            -8,
+            "Invalid nblocks. Must be a positive number or -1.",
+            lambda: self.nodes[0].getnetworkhashps(0),
+        )
+
+        # Genesis block height estimate should return 0
+        hashes_per_second = self.nodes[0].getnetworkhashps(100, 0)
+        assert_equal(hashes_per_second, 0)
+
         # This should be 2 hashes every 10 minutes or 1/300
+        hashes_per_second = self.nodes[0].getnetworkhashps()
         assert abs(hashes_per_second * 300 - 1) < 0.0001
 
     def _test_stopatheight(self):