[tests] Update functional tests documentation

2 files changed, 221 insertions, 107 deletions

diff --git a/test/README.md b/test/README.md
index 4dd512638d..15f6df790f 100644
--- 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> ...
+```
+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
+```
+test/functional/test_runner.py
+```
 
 Run all possible tests with
 
-    test/functional/test_runner.py --extended
+```
+test/functional/test_runner.py --extended
+```
+
+By default, up to 4 tests will be run in parallel by test_runner. To specify
+how many jobs to run, append `--jobs=n`
 
-By default, tests will be run in parallel. To specify how many jobs to run,
-append `--jobs=n` (default n=4).
+The individual tests and the test_runner harness have many command-line
+options. Run `test_runner.py -h` to see them all.
 
-If you want to create a basic coverage report for the RPC test suite, append `--coverage`.
+#### Troubleshooting and debugging test failures
 
-Possible options, which apply to each individual test run:
+##### 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
-output (example: `PYTHON_DEBUG=1 test/functional/test_runner.py wallet`).
+or
+
+```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
-copied into a temporary directory and used as the initial
-test state.
+##### Data directory cache
 
-If you get into a bad state, you should be able
-to recover with:
+A pre-mined blockchain with 200 blocks is generated the first time a
+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 
diff --git a/test/functional/README.md b/test/functional/README.md
index e6c4849702..96fe0becce 100644
--- 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)
-Taken from the [python-bitcoinrpc repository](https://github.com/jgarzik/python-bitcoinrpc).
+### Writing Functional Tests
 
-### [test_framework/test_framework.py](test_framework/test_framework.py)
-Base class for new regression tests.
+#### Example test
 
-### [test_framework/util.py](test_framework/util.py)
-Generally useful functions.
+The [example_test.py](example_test.py) is a heavily commented example of a test case that uses both
+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)
-Basic code to support p2p connectivity to a bitcoind.
+#### Coverage
 
-### [test_framework/comptool.py](test_framework/comptool.py)
-Framework for comparison-tool style, p2p tests.
+Running `test_runner.py` with the `--coverage` argument tracks which RPCs are
+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)
-Utilities for manipulating transaction scripts (originally from python-bitcoinlib)
+#### Style guidelines
 
-### [test_framework/blockstore.py](test_framework/blockstore.py)
-Implements disk-backed block and tx storage.
+- Where possible, try to adhere to [PEP-8 guidelines]([https://www.python.org/dev/peps/pep-0008/)
+- 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)
-Wrapper around OpenSSL EC_Key (originally from python-bitcoinlib)
+#### General test-writing advice
 
-### [test_framework/bignum.py](test_framework/bignum.py)
-Helpers for script.py
+- Set `self.num_nodes` to the minimum number of nodes necessary for the test.
+  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)
-Helper functions for creating blocks and transactions.
+#### RPC and P2P definitions
 
-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
-over the network (```CBlock```, ```CTransaction```, etc, along with the network-level
-wrappers for them, ```msg_block```, ```msg_tx```, etc).
+#### Using the P2P interface
 
-* 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
-a callback class that derives from ```NodeConnCB``` and pass that to the
-```NodeConn``` object, your code will receive the appropriate callbacks when
+- `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
+`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
-different ones to each -- whatever makes the most sense for your test.
-
-* Call ```NetworkThread.start()``` after all ```NodeConn``` objects are created to
+- 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
-is tested.  Examples: ```p2p-accept-block.py```, ```p2p-compactblocks.py```.
+#### Comptool
 
-## 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
-behavior of a bitcoind against 1 or more other bitcoind instances, or against
-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
+- 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.
-Each ```TestInstance``` consists of:
-  - a list of ```[object, outcome, hash]``` entries
-    * ```object``` is a ```CBlock```, ```CTransaction```, or
-    ```CBlockHeader```.  ```CBlock```'s and ```CTransaction```'s are tested for
-    acceptance.  ```CBlockHeader```s can be used so that the test runner can deliver
+- Implement a (generator) function called `get_tests()` which yields `TestInstance`s.
+Each `TestInstance` consists of:
+  - a list of `[object, outcome, hash]` entries
+    * `object` is a `CBlock`, `CTransaction`, or
+    `CBlockHeader`.  `CBlock`'s and `CTransaction`'s are tested for
+    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```
-    or ```False```, the tip is compared with the expected tip -- either the
+    * `outcome` is `True`, `False`, or `None`.  If `True`
+    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_block```, except if the outcome on the last tx is "None",
+  - `sync_every_transaction`: `True/False`.  Analogous to
+    `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
-  ```invalidblockrequest.py``` and ```p2p-fullblocktest.py```.
+- For examples of tests written in this framework, see
+  `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.