Merge bitcoin/bitcoin#22520: test: improve rpc_blockchain.py tests and assert on time and mediantime

ef5e9304cd test: update logging and docstring in rpc_blockchain.py (Jon Atack)
d548dc71e4 test: replace magic values by constants in rpc_blockchain.py (Jon Atack)
78c361086f test: assert on mediantime in getblockheader and getblockchaininfo (Jon Atack)
0a9129c588 test: assert on the value of getblockchaininfo#time (Jon Atack)

Pull request description:

  Follow-up to #22407 improving test coverage per https://github.com/bitcoin/bitcoin/pull/22407#pullrequestreview-702077013.

ACKs for top commit:
  tryphe:
    untested ACK ef5e9304cd

Tree-SHA512: f746d56f430331bc6a2ea7ecd27b21b06275927966aacf1f1127d8d5fdfd930583cabe72e23df3adb2e005da904fc05dc573b8e5eaa2f86e0e193b89a17a5734

test/functional/rpc_blockchain.py

@@ -6,13 +6,15 @@
 
 Test the following RPCs:
     - getblockchaininfo
+    - getchaintxstats
     - gettxoutsetinfo
-    - getdifficulty
-    - getbestblockhash
-    - getblockhash
     - getblockheader
-    - getchaintxstats
+    - getdifficulty
     - getnetworkhashps
+    - waitforblockheight
+    - getblock
+    - getblockhash
+    - getbestblockhash
     - verifychain
 
 Tests correspond to code in rpc/blockchain.cpp.
@@ -49,6 +51,12 @@ from test_framework.util import (
 from test_framework.wallet import MiniWallet
 
 
+HEIGHT = 200  # blocks mined
+TIME_RANGE_STEP = 600  # ten-minute steps
+TIME_RANGE_MTP = TIME_GENESIS_BLOCK + (HEIGHT - 6) * TIME_RANGE_STEP
+TIME_RANGE_END = TIME_GENESIS_BLOCK + HEIGHT * TIME_RANGE_STEP
+
+
 class BlockchainTest(BitcoinTestFramework):
     def set_test_params(self):
         self.setup_clean_chain = True
@@ -71,12 +79,11 @@ class BlockchainTest(BitcoinTestFramework):
         assert self.nodes[0].verifychain(4, 0)
 
     def mine_chain(self):
-        self.log.info('Create some old blocks')
-        for t in range(TIME_GENESIS_BLOCK, TIME_GENESIS_BLOCK + 200 * 600, 600):
-            # ten-minute steps from genesis block time
+        self.log.info(f"Generate {HEIGHT} blocks after the genesis block in ten-minute steps")
+        for t in range(TIME_GENESIS_BLOCK, TIME_RANGE_END, TIME_RANGE_STEP):
             self.nodes[0].setmocktime(t)
             self.nodes[0].generatetoaddress(1, ADDRESS_BCRT1_P2WSH_OP_TRUE)
-        assert_equal(self.nodes[0].getblockchaininfo()['blocks'], 200)
+        assert_equal(self.nodes[0].getblockchaininfo()['blocks'], HEIGHT)
 
     def _test_getblockchaininfo(self):
         self.log.info("Test getblockchaininfo")
@@ -99,7 +106,8 @@ class BlockchainTest(BitcoinTestFramework):
         ]
         res = self.nodes[0].getblockchaininfo()
 
-        assert isinstance(res['time'], int)
+        assert_equal(res['time'], TIME_RANGE_END - TIME_RANGE_STEP)
+        assert_equal(res['mediantime'], TIME_RANGE_MTP)
 
         # result should have these additional pruning keys if manual pruning is enabled
         assert_equal(sorted(res.keys()), sorted(['pruneheight', 'automatic_pruning'] + keys))
@@ -148,8 +156,8 @@ class BlockchainTest(BitcoinTestFramework):
                     'statistics': {
                         'period': 144,
                         'threshold': 108,
-                        'elapsed': 57,
-                        'count': 57,
+                        'elapsed': HEIGHT - 143,
+                        'count': HEIGHT - 143,
                         'possible': True,
                     },
                     'min_activation_height': 0,
@@ -186,33 +194,33 @@ class BlockchainTest(BitcoinTestFramework):
         assert_raises_rpc_error(-8, "blockhash must be of length 64 (not 1, for '0')", self.nodes[0].getchaintxstats, blockhash='0')
         assert_raises_rpc_error(-8, "blockhash must be hexadecimal string (not 'ZZZ0000000000000000000000000000000000000000000000000000000000000')", self.nodes[0].getchaintxstats, blockhash='ZZZ0000000000000000000000000000000000000000000000000000000000000')
         assert_raises_rpc_error(-5, "Block not found", self.nodes[0].getchaintxstats, blockhash='0000000000000000000000000000000000000000000000000000000000000000')
-        blockhash = self.nodes[0].getblockhash(200)
+        blockhash = self.nodes[0].getblockhash(HEIGHT)
         self.nodes[0].invalidateblock(blockhash)
         assert_raises_rpc_error(-8, "Block is not in main chain", self.nodes[0].getchaintxstats, blockhash=blockhash)
         self.nodes[0].reconsiderblock(blockhash)
 
         chaintxstats = self.nodes[0].getchaintxstats(nblocks=1)
         # 200 txs plus genesis tx
-        assert_equal(chaintxstats['txcount'], 201)
+        assert_equal(chaintxstats['txcount'], HEIGHT + 1)
         # tx rate should be 1 per 10 minutes, or 1/600
         # we have to round because of binary math
-        assert_equal(round(chaintxstats['txrate'] * 600, 10), Decimal(1))
+        assert_equal(round(chaintxstats['txrate'] * TIME_RANGE_STEP, 10), Decimal(1))
 
         b1_hash = self.nodes[0].getblockhash(1)
         b1 = self.nodes[0].getblock(b1_hash)
-        b200_hash = self.nodes[0].getblockhash(200)
+        b200_hash = self.nodes[0].getblockhash(HEIGHT)
         b200 = self.nodes[0].getblock(b200_hash)
         time_diff = b200['mediantime'] - b1['mediantime']
 
         chaintxstats = self.nodes[0].getchaintxstats()
         assert_equal(chaintxstats['time'], b200['time'])
-        assert_equal(chaintxstats['txcount'], 201)
+        assert_equal(chaintxstats['txcount'], HEIGHT + 1)
         assert_equal(chaintxstats['window_final_block_hash'], b200_hash)
-        assert_equal(chaintxstats['window_final_block_height'], 200)
-        assert_equal(chaintxstats['window_block_count'], 199)
-        assert_equal(chaintxstats['window_tx_count'], 199)
+        assert_equal(chaintxstats['window_final_block_height'], HEIGHT )
+        assert_equal(chaintxstats['window_block_count'], HEIGHT - 1)
+        assert_equal(chaintxstats['window_tx_count'], HEIGHT - 1)
         assert_equal(chaintxstats['window_interval'], time_diff)
-        assert_equal(round(chaintxstats['txrate'] * time_diff, 10), Decimal(199))
+        assert_equal(round(chaintxstats['txrate'] * time_diff, 10), Decimal(HEIGHT - 1))
 
         chaintxstats = self.nodes[0].getchaintxstats(blockhash=b1_hash)
         assert_equal(chaintxstats['time'], b1['time'])
@@ -229,18 +237,18 @@ class BlockchainTest(BitcoinTestFramework):
         res = node.gettxoutsetinfo()
 
         assert_equal(res['total_amount'], Decimal('8725.00000000'))
-        assert_equal(res['transactions'], 200)
-        assert_equal(res['height'], 200)
-        assert_equal(res['txouts'], 200)
+        assert_equal(res['transactions'], HEIGHT)
+        assert_equal(res['height'], HEIGHT)
+        assert_equal(res['txouts'], HEIGHT)
         assert_equal(res['bogosize'], 16800),
-        assert_equal(res['bestblock'], node.getblockhash(200))
+        assert_equal(res['bestblock'], node.getblockhash(HEIGHT))
         size = res['disk_size']
         assert size > 6400
         assert size < 64000
         assert_equal(len(res['bestblock']), 64)
         assert_equal(len(res['hash_serialized_2']), 64)
 
-        self.log.info("Test that gettxoutsetinfo() works for blockchain with just the genesis block")
+        self.log.info("Test gettxoutsetinfo works for blockchain with just the genesis block")
         b1hash = node.getblockhash(1)
         node.invalidateblock(b1hash)
 
@@ -253,7 +261,7 @@ class BlockchainTest(BitcoinTestFramework):
         assert_equal(res2['bestblock'], node.getblockhash(0))
         assert_equal(len(res2['hash_serialized_2']), 64)
 
-        self.log.info("Test that gettxoutsetinfo() returns the same result after invalidate/reconsider block")
+        self.log.info("Test gettxoutsetinfo returns the same result after invalidate/reconsider block")
         node.reconsiderblock(b1hash)
 
         res3 = node.gettxoutsetinfo()
@@ -262,7 +270,7 @@ class BlockchainTest(BitcoinTestFramework):
         del res['disk_size'], res3['disk_size']
         assert_equal(res, res3)
 
-        self.log.info("Test hash_type option for gettxoutsetinfo()")
+        self.log.info("Test gettxoutsetinfo hash_type option")
         # Adding hash_type 'hash_serialized_2', which is the default, should
         # not change the result.
         res4 = node.gettxoutsetinfo(hash_type='hash_serialized_2')
@@ -286,6 +294,7 @@ class BlockchainTest(BitcoinTestFramework):
         assert_raises_rpc_error(-8, "foohash is not a valid hash_type", node.gettxoutsetinfo, "foohash")
 
     def _test_getblockheader(self):
+        self.log.info("Test getblockheader")
         node = self.nodes[0]
 
         assert_raises_rpc_error(-8, "hash must be of length 64 (not 8, for 'nonsense')", node.getblockheader, "nonsense")
@@ -293,11 +302,11 @@ class BlockchainTest(BitcoinTestFramework):
         assert_raises_rpc_error(-5, "Block not found", node.getblockheader, "0cf7bb8b1697ea987f3b223ba7819250cae33efacb068d23dc24859824a77844")
 
         besthash = node.getbestblockhash()
-        secondbesthash = node.getblockhash(199)
+        secondbesthash = node.getblockhash(HEIGHT - 1)
         header = node.getblockheader(blockhash=besthash)
 
         assert_equal(header['hash'], besthash)
-        assert_equal(header['height'], 200)
+        assert_equal(header['height'], HEIGHT)
         assert_equal(header['confirmations'], 1)
         assert_equal(header['previousblockhash'], secondbesthash)
         assert_is_hex_string(header['chainwork'])
@@ -307,7 +316,7 @@ class BlockchainTest(BitcoinTestFramework):
         assert_is_hash_string(header['merkleroot'])
         assert_is_hash_string(header['bits'], length=None)
         assert isinstance(header['time'], int)
-        assert isinstance(header['mediantime'], int)
+        assert_equal(header['mediantime'], TIME_RANGE_MTP)
         assert isinstance(header['nonce'], int)
         assert isinstance(header['version'], int)
         assert isinstance(int(header['versionHex'], 16), int)
@@ -325,20 +334,23 @@ class BlockchainTest(BitcoinTestFramework):
         assert 'nextblockhash' not in node.getblockheader(node.getbestblockhash())
 
     def _test_getdifficulty(self):
+        self.log.info("Test getdifficulty")
         difficulty = self.nodes[0].getdifficulty()
         # 1 hash in 2 should be valid, so difficulty should be 1/2**31
         # binary => decimal => binary math is why we do this check
         assert abs(difficulty * 2**31 - 1) < 0.0001
 
     def _test_getnetworkhashps(self):
+        self.log.info("Test getnetworkhashps")
         hashes_per_second = self.nodes[0].getnetworkhashps()
         # This should be 2 hashes every 10 minutes or 1/300
         assert abs(hashes_per_second * 300 - 1) < 0.0001
 
     def _test_stopatheight(self):
-        assert_equal(self.nodes[0].getblockcount(), 200)
+        self.log.info("Test stopping at height")
+        assert_equal(self.nodes[0].getblockcount(), HEIGHT)
         self.nodes[0].generatetoaddress(6, ADDRESS_BCRT1_P2WSH_OP_TRUE)
-        assert_equal(self.nodes[0].getblockcount(), 206)
+        assert_equal(self.nodes[0].getblockcount(), HEIGHT + 6)
         self.log.debug('Node should not stop at this height')
         assert_raises(subprocess.TimeoutExpired, lambda: self.nodes[0].process.wait(timeout=3))
         try:
@@ -348,7 +360,7 @@ class BlockchainTest(BitcoinTestFramework):
         self.log.debug('Node should stop at this height...')
         self.nodes[0].wait_until_stopped()
         self.start_node(0)
-        assert_equal(self.nodes[0].getblockcount(), 207)
+        assert_equal(self.nodes[0].getblockcount(), HEIGHT + 7)
 
     def _test_waitforblockheight(self):
         self.log.info("Test waitforblockheight")
@@ -400,20 +412,20 @@ class BlockchainTest(BitcoinTestFramework):
         miniwallet.send_self_transfer(fee_rate=fee_per_kb, from_node=node)
         blockhash = node.generate(1)[0]
 
-        self.log.info("Test that getblock with verbosity 1 doesn't include fee")
+        self.log.info("Test getblock with verbosity 1 doesn't include fee")
         block = node.getblock(blockhash, 1)
         assert 'fee' not in block['tx'][1]
 
-        self.log.info('Test that getblock with verbosity 2 includes expected fee')
+        self.log.info('Test getblock with verbosity 2 includes expected fee')
         block = node.getblock(blockhash, 2)
         tx = block['tx'][1]
         assert 'fee' in tx
         assert_equal(tx['fee'], tx['vsize'] * fee_per_byte)
 
-        self.log.info("Test that getblock with verbosity 2 still works with pruned Undo data")
+        self.log.info("Test getblock with verbosity 2 still works with pruned Undo data")
         datadir = get_datadir_path(self.options.tmpdir, 0)
 
-        self.log.info("Test that getblock with invalid verbosity type returns proper error message")
+        self.log.info("Test getblock with invalid verbosity type returns proper error message")
         assert_raises_rpc_error(-1, "JSON value is not an integer as expected", node.getblock, blockhash, "2")
 
         def move_block_file(old, new):