Merge bitcoin#21042: doc, test: Improve setup_clean_chain documentation

590bda7 scripted-diff: Remove setup_clean_chain if default is not changed (Fabian Jahr)
98892f3 doc: Improve setup_clean_chain documentation (Fabian Jahr)

Pull request description:

  The first commit improves documentation on setup_clean_chain which is misunderstood quite frequently. Most importantly it fixes the TestShell docs which are simply incorrect.

  The second commit removes the instances of `setup_clean_clain` in functional tests where it is not changing the default.

  This used to be part of bitcoin#19168 which also sought to rename`setup_clean_chain`.

ACKs for top commit:
  jonatack:
    ACK 590bda7

Tree-SHA512: a7881186e65d31160b8f84107fb185973b37c6e50f190a85c6e2906a13a7472bb4efa9440bd37fe0a9ac5cd2d1e8559870a7e4380632d9a249eca8980b945f3e

test/functional/README.md

@@ -61,10 +61,13 @@ don't have test cases for.
 - Avoid stop-starting the nodes multiple times during the test if possible. A
   stop-start takes several seconds, so doing it several times blows up the
   runtime of the test.
-- Set the `self.setup_clean_chain` variable in `set_test_params()` to control whether
-  or not to use the cached data directories. The cached data directories
-  contain a 200-block pre-mined blockchain and wallets for four nodes. Each node
-  has 25 mature blocks (25x500=12500 DASH) in its wallet.
+- Set the `self.setup_clean_chain` variable in `set_test_params()` to `True` to
+  initialize an empty blockchain and start from the Genesis block, rather than
+  load a premined blockchain from cache with the default value of `False`. The
+  cached data directories contain a 200-block pre-mined blockchain with the
+  spendable mining rewards being split between four nodes. Each node has 25
+  mature block subsidies (25x500=12500 DASH) in its wallet. Using them is much more
+  efficient than mining blocks in your test.
 - When calling RPCs with lots of arguments, consider using named keyword
   arguments instead of positional arguments to make the intent of the call
   clear to readers.

test/functional/example_test.py

@@ -77,6 +77,9 @@ def set_test_params(self):
         """Override test parameters for your individual test.
 
         This method must be overridden and num_nodes must be explicitly set."""
+        # By default every test loads a pre-mined chain of 200 blocks from cache.
+        # Set setup_clean_chain to True to skip this and start from the Genesis
+        # block.
         self.setup_clean_chain = True
         self.num_nodes = 3
         # Use self.extra_args to change command-line arguments for the nodes

test/functional/feature_asmap.py

@@ -36,7 +36,6 @@ def expected_messages(filename):
 
 class AsmapTest(BitcoinTestFramework):
     def set_test_params(self):
-        self.setup_clean_chain = False
         self.num_nodes = 1
 
     def test_without_asmap_arg(self):

test/functional/feature_dbcrash.py

@@ -49,7 +49,6 @@
 class ChainstateWriteCrashTest(BitcoinTestFramework):
     def set_test_params(self):
         self.num_nodes = 4
-        self.setup_clean_chain = False
         self.rpc_timeout = 480
         self.supports_cli = False
 

test/functional/feature_includeconf.py

@@ -20,7 +20,6 @@
 
 class IncludeConfTest(BitcoinTestFramework):
     def set_test_params(self):
-        self.setup_clean_chain = False
         self.num_nodes = 1
 
     def setup_chain(self):

test/functional/p2p_addr_relay.py

@@ -40,7 +40,6 @@ def on_addr(self, message):
 
 class AddrTest(BitcoinTestFramework):
     def set_test_params(self):
-        self.setup_clean_chain = False
         self.num_nodes = 1
 
     def run_test(self):

test/functional/p2p_blocksonly.py

@@ -12,7 +12,6 @@
 
 class P2PBlocksOnly(BitcoinTestFramework):
     def set_test_params(self):
-        self.setup_clean_chain = False
         self.num_nodes = 1
         self.extra_args = [["-blocksonly"]]
 

test/functional/p2p_filter.py

@@ -49,7 +49,6 @@ def on_tx(self, message):
 
 class FilterTest(BitcoinTestFramework):
     def set_test_params(self):
-        self.setup_clean_chain = False
         self.num_nodes = 1
         self.extra_args = [[
             '-peerbloomfilters',

test/functional/p2p_getaddr_caching.py

@@ -39,7 +39,6 @@ def addr_received(self):
 
 class AddrTest(BitcoinTestFramework):
     def set_test_params(self):
-        self.setup_clean_chain = False
         self.num_nodes = 1
 
     def run_test(self):

test/functional/p2p_invalid_locator.py

@@ -13,7 +13,6 @@
 class InvalidLocatorTest(BitcoinTestFramework):
     def set_test_params(self):
         self.num_nodes = 1
-        self.setup_clean_chain = False
 
     def run_test(self):
         node = self.nodes[0]  # convenience reference to the node

test/functional/p2p_tx_download.py

@@ -52,7 +52,6 @@ def on_getdata(self, message):
 
 class TxDownloadTest(BitcoinTestFramework):
     def set_test_params(self):
-        self.setup_clean_chain = False
         self.num_nodes = 2
 
     def test_tx_requests(self):

test/functional/rpc_estimatefee.py

@@ -14,7 +14,6 @@
 
 class EstimateFeeTest(BitcoinTestFramework):
     def set_test_params(self):
-        self.setup_clean_chain = False
         self.num_nodes = 1
 
     def run_test(self):

test/functional/rpc_psbt.py

@@ -21,7 +21,6 @@
 class PSBTTest(BitcoinTestFramework):
 
     def set_test_params(self):
-        self.setup_clean_chain = False
         self.num_nodes = 3
        # TODO: remove -txindex. Currently required for getrawtransaction call.
         self.extra_args = [

test/functional/test-shell.md

@@ -178,7 +178,7 @@ can be called after the TestShell is shut down.
 | `num_nodes` | `1` | Sets the number of initialized bitcoind processes. |
 | `perf` | False | Profiles running nodes with `perf` for the duration of the test if set to `True`. |
 | `rpc_timeout` | `60` | Sets the RPC server timeout for the underlying bitcoind processes. |
-| `setup_clean_chain` | `False` | Initializes an empty blockchain by default. A 199-block-long chain is initialized if set to `True`. |
+| `setup_clean_chain` | `False` | A 200-block-long chain is initialized from cache by default. Instead, `setup_clean_chain` initializes an empty blockchain if set to `True`. |
 | `randomseed` | Random Integer | `TestShell.options.randomseed` is a member of `TestShell` which can be accessed during a test to seed a random generator. User can override default with a constant value for reproducible test runs. |
 | `supports_cli` | `False` | Whether the bitcoin-cli utility is compiled and available for the test. |
 | `tmpdir` | `"/var/folders/.../"` | Sets directory for test logs. Will be deleted upon a successful test run unless `nocleanup` is set to `True` |

test/functional/wallet_avoidreuse.py

@@ -71,7 +71,6 @@ def assert_balances(node, mine, margin=0.001):
 class AvoidReuseTest(BitcoinTestFramework):
 
     def set_test_params(self):
-        self.setup_clean_chain = False
         self.num_nodes = 2
         # This test isn't testing txn relay/timing, so set whitelist on the
         # peers for instant txn relay. This speeds up the test run time 2-3x.

test/functional/wallet_createwallet.py

@@ -13,7 +13,6 @@
 
 class CreateWalletTest(BitcoinTestFramework):
     def set_test_params(self):
-        self.setup_clean_chain = False
         self.num_nodes = 1
 
     def skip_test_if_missing_module(self):

test/functional/wallet_watchonly.py

@@ -14,7 +14,6 @@
 
 class CreateWalletWatchonlyTest(BitcoinTestFramework):
     def set_test_params(self):
-        self.setup_clean_chain = False
         self.num_nodes = 1
         self.supports_cli = True