Merge bitcoin/bitcoin#26259: test: Test year 2106 block timestamps

fafc96a test: Test year 2106 block timestamps (MacroFake)

Pull request description:

  Alternative to bitcoin/bitcoin#21362 that closes bitcoin/bitcoin#21356

ACKs for top commit:
  Sjors:
    utACK fafc96a

Tree-SHA512: 196d98f42d6f7f0222312b7bd1c68b3bd30cb6f0cbaccb900cfc5fcc689494adb2a7d7d6023c1ff1e8cf871047ec37eeca41386e31029d99cabf9343b4fd2a03

Author: fanquake

test/functional/mining_basic.py

@@ -200,7 +200,7 @@ def assert_submitblock(block, result_str_1, result_str_2=None):
 
         self.log.info("getblocktemplate: Test bad timestamps")
         bad_block = copy.deepcopy(block)
-        bad_block.nTime = 2**31 - 1
+        bad_block.nTime = 2**32 - 1
         assert_template(node, bad_block, 'time-too-new')
         assert_submitblock(bad_block, 'time-too-new', 'time-too-new')
         bad_block.nTime = 0

test/functional/rpc_blockchain.py

@@ -89,6 +89,7 @@ def run_test(self):
         self._test_waitforblockheight()
         self._test_getblock()
         self._test_getdeploymentinfo()
+        self._test_y2106()
         assert self.nodes[0].verifychain(4, 0)
 
     def mine_chain(self):
@@ -255,6 +256,14 @@ def _test_getdeploymentinfo(self):
         # calling with an explicit hash works
         self.check_signalling_deploymentinfo_result(self.nodes[0].getdeploymentinfo(gbci207["bestblockhash"]), gbci207["blocks"], gbci207["bestblockhash"], "started")
 
+    def _test_y2106(self):
+        self.log.info("Check that block timestamps work until year 2106")
+        self.generate(self.nodes[0], 8)[-1]
+        time_2106 = 2**32 - 1
+        self.nodes[0].setmocktime(time_2106)
+        last = self.generate(self.nodes[0], 6)[-1]
+        assert_equal(self.nodes[0].getblockheader(last)["mediantime"], time_2106)
+
     def _test_getchaintxstats(self):
         self.log.info("Test getchaintxstats")