Functional tests

The /test/ (/test/) directory contains integration tests that test bitcoind and its utilities in their entirety. It does not contain unit tests, which can be found in /src/test (/src/test), /src/wallet/test (/src/wallet/test), etc.

There are currently two sets of tests in the /test/ (/test/) directory:

The util tests are run as part of make check target. The functional tests are run by the Teamcity continuous build process whenever a diff is created or updated on Phabricator. Both sets of tests can also be run locally.

Running functional 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


The ZMQ functional test requires a python ZMQ library. To install it:

Running the tests

Individual tests can be run by directly calling the test script, eg:


or can be run through the test_runner harness, eg:

test/functional/ example_test

You can run any combination (incl. duplicates) of tests by calling:

test/functional/ <testname1> <testname2> <testname3> ...

Run the regression test suite with:


Run all possible tests with

test/functional/ --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

The individual tests and the test_runner harness have many command-line options. Run test/functional/ -h to see them all.

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.

killall bitcoind


pkill -9 bitcoind
Data directory cache

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):

rm -rf test/cache
killall bitcoind
Test logging

The tests contain logging at different levels (debug, info, warning, etc). By default:

These log files can be located under the test data directory (which is always printed in the first line of test output):

The node number identifies the relevant test node, starting from node0, which corresponds to its position in the nodes list of the specific test, e.g. self.nodes[0].

To change the level of logs output to the console, use the -l command line argument.

test_framework.log and bitcoind debug.logs can be combined into a single aggregate log by running the script. The output can be plain text, colorized text or html. For example:

test/functional/ -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:

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.

If further introspection of the bitcoind instances themselves becomes necessary, this can be accomplished by first setting a pdb breakpoint at an appropriate location, running the test to that point, then using gdb (or lldb on macOS) to attach to the process and debug.

For instance, to attach to self.node[1] during a run you can get the pid of the node within pdb.

(pdb) self.node[1]

Alternatively, you can find the pid by inspecting the temp folder for the specific test you are running. The path to that folder is printed at the beginning of every test run:

2017-06-27 14:13:56.686000 TestFramework (INFO): Initializing test directory /tmp/user/1000/testo9vsdjo3

Use the path to find the pid file in the temp folder:

cat /tmp/user/1000/testo9vsdjo3/node1/regtest/

Then you can use the pid to start gdb:

gdb /home/example/bitcoind <pid>

Note: gdb attach step may require sudo. To get rid of this, you can run:

echo 0 | sudo tee /proc/sys/kernel/yama/ptrace_scope

Often while debugging rpc calls from functional tests, the test might reach timeout before process can return a response. Use --timeout-factor 0 to disable all rpc timeouts for that particular functional test. Ex: test/functional/ wallet_hd --timeout-factor 0.

Benchmarking and profiling with perf

An easy way to profile node performance during functional tests is provided for Linux platforms using perf.

Perf will sample the running node and will generate profile data in the node’s datadir. The profile data can then be presented using perf report or a graphical tool like hotspot.

There are two ways of invoking perf: one is to use the --perf flag when running tests, which will profile each node during the entire test run: perf begins to profile when the node starts and ends when it shuts down. The other way is the use the profile_with_perf context manager, e.g.

with node.profile_with_perf("send-big-msgs"):
    # Perform activity on the node you're interested in profiling, e.g.:
    for _ in range(10000):

To see useful textual output, run

perf report -i /path/to/datadir/ --stdio | c++filt | less

See also:

Prevent using deprecated features

Python will issue a DeprecationWarning when a deprecated feature is encountered in a script. By default, this warning message is ignored and not displayed to the user. This behavior can be changed by setting the environment variable PYTHONWARNINGS as follow:


The warning message will now be printed to the sys.stderr output.

Util tests

Util tests can be run locally by running test/util/ Use the -v option for verbose output.

Writing functional tests

Example test

The file test/functional/ (/test/functional/ 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.


Running test/functional/ 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.

Style guidelines

Naming guidelines

General test-writing advice

RPC and P2P definitions

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:

Using the P2P interface

P2PConnections can be used as such:

p2p_conn = node.add_p2p_connection(P2PInterface())

They can also be referenced by indexing into a TestNode’s p2ps list, which contains the list of test framework p2p objects connected to itself (it does not include any TestNodes):


More examples can be found in (/test/functional/, (/test/functional/

Prototyping tests

The TestShell class exposes the BitcoinTestFramework functionality to interactive Python3 environments and can be used to prototype tests. This may be especially useful in a REPL environment with session logging utilities, such as IPython. The logs of such interactive sessions can later be adapted into permanent test cases.

Test framework modules

The following are useful modules for test developers. They are located in test/functional/test_framework/ (/test/functional/test_framework). (/test/functional/test_framework/

Taken from the python-bitcoinrpc repository. (/test/functional/test_framework/

Base class for functional tests. (/test/functional/test_framework/

Generally useful functions. (/test/functional/test_framework/

Test objects for interacting with a bitcoind node over the p2p interface. (/test/functional/test_framework/

Utilities for manipulating transaction scripts (originally from python-bitcoinlib) (/test/functional/test_framework/

Test-only secp256k1 elliptic curve implementation (/test/functional/test_framework/

Helper functions for creating blocks and transactions.