Merge #10612: The young person's guide to the test_framework

e7ba6c1 [tests] add example test (John Newbery) 76859e6 [tests] Update functional tests documentation (John Newbery) Tree-SHA512: 74eb464e965e16466f95b9eda7d1e89a31ef1ef204dd30e1b11ddf482336f12f33fa5ca3cc733b6eaf440c46401e663585af9caca202deddb440bbadce964a62
8 years ago · 7c87a9c748
4 changed files with 441 additions and 107 deletions
--- a/test/README.md
+++ b/test/README.md
@ -15,84 +15,152 @@ The util tests are run as part of `make check` target. The functional
 tests are run by the travis continuous build process whenever a pull
 request is opened. Both sets of tests can also be run locally.
-Functional Test dependencies
+# Running tests locally
-============================
+
 Build for your system first. Be sure to enable wallet, utils and daemon when you configure. Tests will not run otherwise.
 ### Functional tests
 #### Dependencies
 The ZMQ functional test requires a python ZMQ library. To install it:
 - on Unix, run `sudo apt-get install python3-zmq`
 - on mac OS, run `pip3 install pyzmq`
-Running tests locally
+#### Running the tests
 =====================
-Build for your system first. Be sure to enable wallet, utils and daemon when you configure. Tests will not run otherwise.
+Individual tests can be run by directly calling the test script, eg:
-Functional tests
+```
----------------
+test/functional/replace-by-fee.py
 ```
-You can run any single test by calling
+or can be run through the test_runner harness, eg:
-    test/functional/test_runner.py <testname>
+```
 test/functional/test_runner.py replace-by-fee.py
 ```
-Or you can run any combination (incl. duplicates) of tests by calling
+You can run any combination (incl. duplicates) of tests by calling:
 ```
 test/functional/test_runner.py <testname1> <testname2> <testname3> ...
 ```
-Run the regression test suite with
+Run the regression test suite with:
 ```
 test/functional/test_runner.py
 ```
 Run all possible tests with
 ```
 test/functional/test_runner.py --extended
 ```
-By default, tests will be run in parallel. To specify how many jobs to run,
+By default, up to 4 tests will be run in parallel by test_runner. To specify
-append `--jobs=n` (default n=4).
+how many jobs to run, append `--jobs=n`
-If you want to create a basic coverage report for the RPC test suite, append `--coverage`.
+The individual tests and the test_runner harness have many command-line
 options. Run `test_runner.py -h` to see them all.
-Possible options, which apply to each individual test run:
+#### Troubleshooting and debugging test failures
 ##### Resource contention
 The P2P and RPC ports used by the bitcoind nodes-under-test are chosen to make
 conflicts with other processes unlikely. However, if there is another bitcoind
 process running on the system (perhaps from a previous test which hasn't successfully
 killed all its bitcoind nodes), then there may be a port conflict which will
 cause the test to fail. It is recommended that you run the tests on a system
 where no other bitcoind processes are running.
 On linux, the test_framework will warn if there is another
 bitcoind process running when the tests are started.
 If there are zombie bitcoind processes after test failure, you can kill them
 by running the following commands. **Note that these commands will kill all
 bitcoind processes running on the system, so should not be used if any non-test
 bitcoind processes are being run.**
 ```bash
 killall bitcoind
 ```
  -h, --help            show this help message and exit
  --nocleanup           Leave bitcoinds and test.* datadir on exit or error
  --noshutdown          Don't stop bitcoinds after the test execution
  --srcdir=SRCDIR       Source directory containing bitcoind/bitcoin-cli
                        (default: ../../src)
  --tmpdir=TMPDIR       Root directory for datadirs
  --tracerpc            Print out all RPC calls as they are made
  --coveragedir=COVERAGEDIR
                        Write tested RPC commands into this directory
 ```
-If you set the environment variable `PYTHON_DEBUG=1` you will get some debug
+or
-output (example: `PYTHON_DEBUG=1 test/functional/test_runner.py wallet`).
+
 ```bash
 pkill -9 bitcoind
 ```
 A 200-block -regtest blockchain and wallets for four nodes
 is created the first time a regression test is run and
 is stored in the cache/ directory. Each node has 25 mature
 blocks (25*50=1250 BTC) in its wallet.
-After the first run, the cache/ blockchain and wallets are
+##### Data directory cache
 copied into a temporary directory and used as the initial
 test state.
-If you get into a bad state, you should be able
+A pre-mined blockchain with 200 blocks is generated the first time a
-to recover with:
+functional test is run and is stored in test/cache. This speeds up
 test startup times since new blockchains don't need to be generated for
 each test. However, the cache may get into a bad state, in which case
 tests will fail. If this happens, remove the cache directory (and make
 sure bitcoind processes are stopped as above):
 ```bash
 rm -rf cache
 killall bitcoind
 ```
-Util tests
+##### Test logging
----------
+
 The tests contain logging at different levels (debug, info, warning, etc). By
 default:
 - when run through the test_runner harness, *all* logs are written to
  `test_framework.log` and no logs are output to the console.
 - when run directly, *all* logs are written to `test_framework.log` and INFO
  level and above are output to the console.
 - when run on Travis, no logs are output to the console. However, if a test
  fails, the `test_framework.log` and bitcoind `debug.log`s will all be dumped
  to the console to help troubleshooting.
 To change the level of logs output to the console, use the `-l` command line
 argument.
 `test_framework.log` and bitcoind `debug.log`s can be combined into a single
 aggregate log by running the `combine_logs.py` script. The output can be plain
 text, colorized text or html. For example:
 ```
 combine_logs.py -c <test data directory> | less -r
 ```
 will pipe the colorized logs from the test into less.
 Use `--tracerpc` to trace out all the RPC calls and responses to the console. For
 some tests (eg any that use `submitblock` to submit a full block over RPC),
 this can result in a lot of screen output.
 By default, the test data directory will be deleted after a successful run.
 Use `--nocleanup` to leave the test data directory intact. The test data
 directory is never deleted after a failed test.
 ##### Attaching a debugger
 A python debugger can be attached to tests at any point. Just add the line:
 ```py
 import pdb; pdb.set_trace()
 ```
 anywhere in the test. You will then be able to inspect variables, as well as
 call methods that interact with the bitcoind nodes-under-test.
 ### Util tests
 Util tests can be run locally by running `test/util/bitcoin-util-test.py`. 
 Use the `-v` option for verbose output.
-Writing functional tests
+# Writing functional tests
 ========================
 You are encouraged to write functional tests for new or existing features.
 Further information about the functional test framework and individual 
--- a/test/functional/README.md
+++ b/test/functional/README.md
@ -1,108 +1,154 @@
-Regression tests
+# Functional tests
 ================
-### [test_framework/authproxy.py](test_framework/authproxy.py)
+### Writing Functional Tests
 Taken from the [python-bitcoinrpc repository](https://github.com/jgarzik/python-bitcoinrpc).
-### [test_framework/test_framework.py](test_framework/test_framework.py)
+#### Example test
 Base class for new regression tests.
-### [test_framework/util.py](test_framework/util.py)
+The [example_test.py](example_test.py) is a heavily commented example of a test case that uses both
-Generally useful functions.
+the RPC and P2P interfaces. If you are writing your first test, copy that file
 and modify to fit your needs.
-### [test_framework/mininode.py](test_framework/mininode.py)
+#### Coverage
 Basic code to support p2p connectivity to a bitcoind.
-### [test_framework/comptool.py](test_framework/comptool.py)
+Running `test_runner.py` with the `--coverage` argument tracks which RPCs are
-Framework for comparison-tool style, p2p tests.
+called by the tests and prints a report of uncovered RPCs in the summary. This
 can be used (along with the `--extended` argument) to find out which RPCs we
 don't have test cases for.
-### [test_framework/script.py](test_framework/script.py)
+#### Style guidelines
 Utilities for manipulating transaction scripts (originally from python-bitcoinlib)
-### [test_framework/blockstore.py](test_framework/blockstore.py)
+- Where possible, try to adhere to [PEP-8 guidelines]([https://www.python.org/dev/peps/pep-0008/)
-Implements disk-backed block and tx storage.
+- Use a python linter like flake8 before submitting PRs to catch common style
  nits (eg trailing whitespace, unused imports, etc)
 - Avoid wildcard imports where possible
 - Use a module-level docstring to describe what the test is testing, and how it
  is testing it.
 - When subclassing the BitcoinTestFramwork, place overrides for the
  `__init__()`, and `setup_xxxx()` methods at the top of the subclass, then
  locally-defined helper methods, then the `run_test()` method.
-### [test_framework/key.py](test_framework/key.py)
+#### General test-writing advice
 Wrapper around OpenSSL EC_Key (originally from python-bitcoinlib)
-### [test_framework/bignum.py](test_framework/bignum.py)
+- Set `self.num_nodes` to the minimum number of nodes necessary for the test.
-Helpers for script.py
+  Having additional unrequired nodes adds to the execution time of the test as
  well as memory/CPU/disk requirements (which is important when running tests in
  parallel or on Travis).
 - 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 `__init__()` 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 (25x50=1250 BTC) in its wallet.
 - 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_framework/blocktools.py](test_framework/blocktools.py)
+#### RPC and P2P definitions
 Helper functions for creating blocks and transactions.
-P2P test design notes
+Test writers may find it helpful to refer to the definitions for the RPC and
---------------------
+P2P messages. These can be found in the following source files:
-## Mininode
+- `/src/rpc/*` for RPCs
 - `/src/wallet/rpc*` for wallet RPCs
 - `ProcessMessage()` in `/src/net_processing.cpp` for parsing P2P messages
-* ```mininode.py``` contains all the definitions for objects that pass
+#### Using the P2P interface
 over the network (```CBlock```, ```CTransaction```, etc, along with the network-level
 wrappers for them, ```msg_block```, ```msg_tx```, etc).
-* P2P tests have two threads.  One thread handles all network communication
+- `mininode.py` contains all the definitions for objects that pass
 over the network (`CBlock`, `CTransaction`, etc, along with the network-level
 wrappers for them, `msg_block`, `msg_tx`, etc).
 - P2P tests have two threads. One thread handles all network communication
 with the bitcoind(s) being tested (using python's asyncore package); the other
 implements the test logic.
-* ```NodeConn``` is the class used to connect to a bitcoind.  If you implement
+- `NodeConn` is the class used to connect to a bitcoind.  If you implement
-a callback class that derives from ```NodeConnCB``` and pass that to the
+a callback class that derives from `NodeConnCB` and pass that to the
-```NodeConn``` object, your code will receive the appropriate callbacks when
+`NodeConn` object, your code will receive the appropriate callbacks when
 events of interest arrive.
-* You can pass the same handler to multiple ```NodeConn```'s if you like, or pass
+- Call `NetworkThread.start()` after all `NodeConn` objects are created to
 different ones to each -- whatever makes the most sense for your test.
 * Call ```NetworkThread.start()``` after all ```NodeConn``` objects are created to
 start the networking thread.  (Continue with the test logic in your existing
 thread.)
-* RPC calls are available in p2p tests.
+- Can be used to write tests where specific P2P protocol behavior is tested.
 Examples tests are `p2p-accept-block.py`, `p2p-compactblocks.py`.
-* Can be used to write free-form tests, where specific p2p-protocol behavior
+#### Comptool
 is tested.  Examples: ```p2p-accept-block.py```, ```p2p-compactblocks.py```.
-## Comptool
+- Comptool is a Testing framework for writing tests that compare the block/tx acceptance
 behavior of a bitcoind against 1 or more other bitcoind instances. It should not be used
 to write static tests with known outcomes, since that type of test is easier to write and
 maintain using the standard BitcoinTestFramework.
-* Testing framework for writing tests that compare the block/tx acceptance
+- Set the `num_nodes` variable (defined in `ComparisonTestFramework`) to start up
-behavior of a bitcoind against 1 or more other bitcoind instances, or against
+1 or more nodes.  If using 1 node, then `--testbinary` can be used as a command line
 known outcomes, or both.
 * Set the ```num_nodes``` variable (defined in ```ComparisonTestFramework```) to start up
 1 or more nodes.  If using 1 node, then ```--testbinary``` can be used as a command line
 option to change the bitcoind binary used by the test.  If using 2 or more nodes,
-then ```--refbinary``` can be optionally used to change the bitcoind that will be used
+then `--refbinary` can be optionally used to change the bitcoind that will be used
 on nodes 2 and up.
-* Implement a (generator) function called ```get_tests()``` which yields ```TestInstance```s.
+- Implement a (generator) function called `get_tests()` which yields `TestInstance`s.
-Each ```TestInstance``` consists of:
+Each `TestInstance` consists of:
-  - a list of ```[object, outcome, hash]``` entries
+  - a list of `[object, outcome, hash]` entries
-    * ```object``` is a ```CBlock```, ```CTransaction```, or
+    * `object` is a `CBlock`, `CTransaction`, or
-    ```CBlockHeader```.  ```CBlock```'s and ```CTransaction```'s are tested for
+    `CBlockHeader`.  `CBlock`'s and `CTransaction`'s are tested for
-    acceptance.  ```CBlockHeader```s can be used so that the test runner can deliver
+    acceptance.  `CBlockHeader`s can be used so that the test runner can deliver
    complete headers-chains when requested from the bitcoind, to allow writing
    tests where blocks can be delivered out of order but still processed by
    headers-first bitcoind's.
-    * ```outcome``` is ```True```, ```False```, or ```None```.  If ```True```
+    * `outcome` is `True`, `False`, or `None`.  If `True`
-    or ```False```, the tip is compared with the expected tip -- either the
+    or `False`, the tip is compared with the expected tip -- either the
    block passed in, or the hash specified as the optional 3rd entry.  If
-    ```None``` is specified, then the test will compare all the bitcoind's
+    `None` is specified, then the test will compare all the bitcoind's
    being tested to see if they all agree on what the best tip is.
-    * ```hash``` is the block hash of the tip to compare against. Optional to
+    * `hash` is the block hash of the tip to compare against. Optional to
    specify; if left out then the hash of the block passed in will be used as
    the expected tip.  This allows for specifying an expected tip while testing
    the handling of either invalid blocks or blocks delivered out of order,
    which complete a longer chain.
-  - ```sync_every_block```: ```True/False```.  If ```False```, then all blocks
+  - `sync_every_block`: `True/False`.  If `False`, then all blocks
    are inv'ed together, and the test runner waits until the node receives the
    last one, and tests only the last block for tip acceptance using the
-    outcome and specified tip.  If ```True```, then each block is tested in
+    outcome and specified tip.  If `True`, then each block is tested in
    sequence and synced (this is slower when processing many blocks).
-  - ```sync_every_transaction```: ```True/False```.  Analogous to
+  - `sync_every_transaction`: `True/False`.  Analogous to
-    ```sync_every_block```, except if the outcome on the last tx is "None",
+    `sync_every_block`, except if the outcome on the last tx is "None",
    then the contents of the entire mempool are compared across all bitcoind
-    connections.  If ```True``` or ```False```, then only the last tx's
+    connections.  If `True` or `False`, then only the last tx's
    acceptance is tested against the given outcome.
-* For examples of tests written in this framework, see
+- For examples of tests written in this framework, see
-  ```invalidblockrequest.py``` and ```p2p-fullblocktest.py```.
+  `invalidblockrequest.py` and `p2p-fullblocktest.py`.
 ### test-framework modules
 #### [test_framework/authproxy.py](test_framework/authproxy.py)
 Taken from the [python-bitcoinrpc repository](https://github.com/jgarzik/python-bitcoinrpc).
 #### [test_framework/test_framework.py](test_framework/test_framework.py)
 Base class for functional tests.
 #### [test_framework/util.py](test_framework/util.py)
 Generally useful functions.
 #### [test_framework/mininode.py](test_framework/mininode.py)
 Basic code to support P2P connectivity to a bitcoind.
 #### [test_framework/comptool.py](test_framework/comptool.py)
 Framework for comparison-tool style, P2P tests.
 #### [test_framework/script.py](test_framework/script.py)
 Utilities for manipulating transaction scripts (originally from python-bitcoinlib)
 #### [test_framework/blockstore.py](test_framework/blockstore.py)
 Implements disk-backed block and tx storage.
 #### [test_framework/key.py](test_framework/key.py)
 Wrapper around OpenSSL EC_Key (originally from python-bitcoinlib)
 #### [test_framework/bignum.py](test_framework/bignum.py)
 Helpers for script.py
 #### [test_framework/blocktools.py](test_framework/blocktools.py)
 Helper functions for creating blocks and transactions.
--- a/test/functional/example_test.py
+++ b/test/functional/example_test.py
@ -0,0 +1,219 @@
 #!/usr/bin/env python3
 # Copyright (c) 2017 The Bitcoin Core developers
 # Distributed under the MIT software license, see the accompanying
 # file COPYING or http://www.opensource.org/licenses/mit-license.php.
 """An example functional test
 The module-level docstring should include a high-level description of
 what the test is doing. It's the first thing people see when they open
 the file and should give the reader information about *what* the test
 is testing and *how* it's being tested
 """
 # Imports should be in PEP8 ordering (std library first, then third party
 # libraries then local imports).
 from collections import defaultdict
 # Avoid wildcard * imports if possible
 from test_framework.blocktools import (create_block, create_coinbase)
 from test_framework.mininode import (
    CInv,
    NetworkThread,
    NodeConn,
    NodeConnCB,
    mininode_lock,
    msg_block,
    msg_getdata,
    wait_until,
 )
 from test_framework.test_framework import BitcoinTestFramework
 from test_framework.util import (
    assert_equal,
    connect_nodes,
    p2p_port,
 )
 # NodeConnCB is a class containing callbacks to be executed when a P2P
 # message is received from the node-under-test. Subclass NodeConnCB and
 # override the on_*() methods if you need custom behaviour.
 class BaseNode(NodeConnCB):
    def __init__(self):
        """Initialize the NodeConnCB
        Used to inialize custom properties for the Node that aren't
        included by default in the base class. Be aware that the NodeConnCB
        base class already stores a counter for each P2P message type and the
        last received message of each type, which should be sufficient for the
        needs of most tests.
        Call super().__init__() first for standard initialization and then
        initialize custom properties."""
        super().__init__()
        # Stores a dictionary of all blocks received
        self.block_receive_map = defaultdict(int)
    def on_block(self, conn, message):
        """Override the standard on_block callback
        Store the hash of a received block in the dictionary."""
        message.block.calc_sha256()
        self.block_receive_map[message.block.sha256] += 1
 def custom_function():
    """Do some custom behaviour
    If this function is more generally useful for other tests, consider
    moving it to a module in test_framework."""
    # self.log.info("running custom_function")  # Oops! Can't run self.log outside the BitcoinTestFramework
    pass
 class ExampleTest(BitcoinTestFramework):
    # Each functional test is a subclass of the BitcoinTestFramework class.
    # Override the __init__(), add_options(), setup_chain(), setup_network()
    # and setup_nodes() methods to customize the test setup as required.
    def __init__(self):
        """Initialize the test
        Call super().__init__() first, and then override any test parameters
        for your individual test."""
        super().__init__()
        self.setup_clean_chain = True
        self.num_nodes = 3
        # Use self.extra_args to change command-line arguments for the nodes
        self.extra_args = [[], ["-logips"], []]
        # self.log.info("I've finished __init__")  # Oops! Can't run self.log before run_test()
    # Use add_options() to add specific command-line options for your test.
    # In practice this is not used very much, since the tests are mostly written
    # to be run in automated environments without command-line options.
    # def add_options()
    #     pass
    # Use setup_chain() to customize the node data directories. In practice
    # this is not used very much since the default behaviour is almost always
    # fine
    # def setup_chain():
    #     pass
    def setup_network(self):
        """Setup the test network topology
        Often you won't need to override this, since the standard network topology
        (linear: node0 <-> node1 <-> node2 <-> ...) is fine for most tests.
        If you do override this method, remember to start the nodes, assign
        them to self.nodes, connect them and then sync."""
        self.setup_nodes()
        # In this test, we're not connecting node2 to node0 or node1. Calls to
        # sync_all() should not include node2, since we're not expecting it to
        # sync.
        connect_nodes(self.nodes[0], 1)
        self.sync_all([self.nodes[0:1]])
    # Use setup_nodes() to customize the node start behaviour (for example if
    # you don't want to start all nodes at the start of the test).
    # def setup_nodes():
    #     pass
    def custom_method(self):
        """Do some custom behaviour for this test
        Define it in a method here because you're going to use it repeatedly.
        If you think it's useful in general, consider moving it to the base
        BitcoinTestFramework class so other tests can use it."""
        self.log.info("Running custom_method")
    def run_test(self):
        """Main test logic"""
        # Create a P2P connection to one of the nodes
        node0 = BaseNode()
        connections = []
        connections.append(NodeConn('127.0.0.1', p2p_port(0), self.nodes[0], node0))
        node0.add_connection(connections[0])
        # Start up network handling in another thread. This needs to be called
        # after the P2P connections have been created.
        NetworkThread().start()
        # wait_for_verack ensures that the P2P connection is fully up.
        node0.wait_for_verack()
        # Generating a block on one of the nodes will get us out of IBD
        blocks = [int(self.nodes[0].generate(nblocks=1)[0], 16)]
        self.sync_all([self.nodes[0:1]])
        # Notice above how we called an RPC by calling a method with the same
        # name on the node object. Notice also how we used a keyword argument
        # to specify a named RPC argument. Neither of those are defined on the
        # node object. Instead there's some __getattr__() magic going on under
        # the covers to dispatch unrecognised attribute calls to the RPC
        # interface.
        # Logs are nice. Do plenty of them. They can be used in place of comments for
        # breaking the test into sub-sections.
        self.log.info("Starting test!")
        self.log.info("Calling a custom function")
        custom_function()
        self.log.info("Calling a custom method")
        self.custom_method()
        self.log.info("Create some blocks")
        self.tip = int(self.nodes[0].getbestblockhash(), 16)
        self.block_time = self.nodes[0].getblock(self.nodes[0].getbestblockhash())['time'] + 1
        height = 1
        for i in range(10):
            # Use the mininode and blocktools functionality to manually build a block
            # Calling the generate() rpc is easier, but this allows us to exactly
            # control the blocks and transactions.
            block = create_block(self.tip, create_coinbase(height), self.block_time)
            block.solve()
            block_message = msg_block(block)
            # Send message is used to send a P2P message to the node over our NodeConn connection
            node0.send_message(block_message)
            self.tip = block.sha256
            blocks.append(self.tip)
            self.block_time += 1
            height += 1
        self.log.info("Wait for node1 to reach current tip (height 11) using RPC")
        self.nodes[1].waitforblockheight(11)
        self.log.info("Connect node2 and node1")
        connect_nodes(self.nodes[1], 2)
        self.log.info("Add P2P connection to node2")
        node2 = BaseNode()
        connections.append(NodeConn('127.0.0.1', p2p_port(2), self.nodes[2], node2))
        node2.add_connection(connections[1])
        node2.wait_for_verack()
        self.log.info("Wait for node2 reach current tip. Test that it has propogated all the blocks to us")
        for block in blocks:
            getdata_request = msg_getdata()
            getdata_request.inv.append(CInv(2, block))
            node2.send_message(getdata_request)
        # wait_until() will loop until a predicate condition is met. Use it to test properties of the
        # NodeConnCB objects.
        assert wait_until(lambda: sorted(blocks) == sorted(list(node2.block_receive_map.keys())), timeout=5)
        self.log.info("Check that each block was received only once")
        # The network thread uses a global lock on data access to the NodeConn objects when sending and receiving
        # messages. The test thread should acquire the global lock before accessing any NodeConn data to avoid locking
        # and synchronization issues. Note wait_until() acquires this global lock when testing the predicate.
        with mininode_lock:
            for block in node2.block_receive_map.values():
                assert_equal(block, 1)
 if __name__ == '__main__':
    ExampleTest().main()
--- a/test/functional/test_runner.py
+++ b/test/functional/test_runner.py
@ -139,6 +139,7 @@ EXTENDED_SCRIPTS = [
    'bip65-cltv-p2p.py',
    'bipdersig-p2p.py',
    'bipdersig.py',
    'example_test.py',
    'getblocktemplate_proposals.py',
    'txn_doublespend.py',
    'txn_clone.py --mineblock',