litecoin/test/functional/test-shell.md

Test Shell for Interactive Environments

This document describes how to use the TestShell submodule in the functional test suite.

The TestShell submodule extends the BitcoinTestFramework functionality to external interactive environments for prototyping and educational purposes. Just like BitcoinTestFramework, the TestShell allows the user to:

• Manage regtest bitcoind subprocesses.
• Access RPC interfaces of the underlying bitcoind instances.
• Log events to the functional test logging utility.

The TestShell can be useful in interactive environments where it is necessary to extend the object lifetime of the underlying BitcoinTestFramework between user inputs. Such environments include the Python3 command line interpreter or Jupyter notebooks running a Python3 kernel.

1. Requirements

• Python3
• bitcoind built in the same repository as the TestShell.

2. Importing TestShell from the Bitcoin Core repository

We can import the TestShell by adding the path of the Bitcoin Core test_framework module to the beginning of the PATH variable, and then importing the TestShell class from the test_shell sub-package.

>>> import sys
>>> sys.path.insert(0, "/path/to/bitcoin/test/functional")
>>> from test_framework.test_shell import TestShell

The following TestShell methods manage the lifetime of the underlying bitcoind processes and logging utilities.

• TestShell.setup()
• TestShell.shutdown()

The TestShell inherits all BitcoinTestFramework members and methods, such as:

• TestShell.nodes[index].rpc_method()
• TestShell.log.info("Custom log message")

The following sections demonstrate how to initialize, run, and shut down a TestShell object.

3. Initializing a TestShell object

>>> test = TestShell().setup(num_nodes=2, setup_clean_chain=True)
20XX-XX-XXTXX:XX:XX.XXXXXXX TestFramework (INFO): Initializing test directory /path/to/bitcoin_func_test_XXXXXXX

The TestShell forwards all functional test parameters of the parent BitcoinTestFramework object. The full set of argument keywords which can be used to initialize the TestShell can be found in section #6 of this document.

Note: Running multiple instances of TestShell is not allowed. Running a single process also ensures that logging remains consolidated in the same temporary folder. If you need more bitcoind nodes than set by default (1), simply increase the num_nodes parameter during setup.

>>> test2 = TestShell().setup()
TestShell is already running!

4. Interacting with the TestShell

Unlike the BitcoinTestFramework class, the TestShell keeps the underlying Bitcoind subprocesses (nodes) and logging utilities running until the user explicitly shuts down the TestShell object.

During the time between the setup and shutdown calls, all bitcoind node processes and BitcoinTestFramework convenience methods can be accessed interactively.

Example: Mining a regtest chain

By default, the TestShell nodes are initialized with a clean chain. This means that each node of the TestShell is initialized with a block height of 0.

>>> test.nodes[0].getblockchaininfo()["blocks"]
0

We now let the first node generate 101 regtest blocks, and direct the coinbase rewards to a wallet address owned by the mining node.

>>> address = test.nodes[0].getnewaddress()
>>> test.nodes[0].generatetoaddress(101, address)
['2b98dd0044aae6f1cca7f88a0acf366a4bfe053c7f7b00da3c0d115f03d67efb', ...

Since the two nodes are both initialized by default to establish an outbound connection to each other during setup, the second node's chain will include the mined blocks as soon as they propagate.

>>> test.nodes[1].getblockchaininfo()["blocks"]
101

The block rewards from the first block are now spendable by the wallet of the first node.

>>> test.nodes[0].getbalance()
Decimal('50.00000000')

We can also log custom events to the logger.

>>> test.nodes[0].log.info("Successfully mined regtest chain!")
20XX-XX-XXTXX:XX:XX.XXXXXXX TestFramework.node0 (INFO): Successfully mined regtest chain!

Note: Please also consider the functional test readme, which provides an overview of the test-framework. Modules such as key.py, script.py and messages.py are particularly useful in constructing objects which can be passed to the bitcoind nodes managed by a running TestShell object.

5. Shutting the TestShell down

Shutting down the TestShell will safely tear down all running bitcoind instances and remove all temporary data and logging directories.

>>> test.shutdown()
20XX-XX-XXTXX:XX:XX.XXXXXXX TestFramework (INFO): Stopping nodes
20XX-XX-XXTXX:XX:XX.XXXXXXX TestFramework (INFO): Cleaning up /path/to/bitcoin_func_test_XXXXXXX on exit
20XX-XX-XXTXX:XX:XX.XXXXXXX TestFramework (INFO): Tests successful

To prevent the logs from being removed after a shutdown, simply set the TestShell.options.nocleanup member to True.

>>> test.options.nocleanup = True
>>> test.shutdown()
20XX-XX-XXTXX:XX:XX.XXXXXXX TestFramework (INFO): Stopping nodes
20XX-XX-XXTXX:XX:XX.XXXXXXX TestFramework (INFO): Not cleaning up dir /path/to/bitcoin_func_test_XXXXXXX on exit
20XX-XX-XXTXX:XX:XX.XXXXXXX TestFramework (INFO): Tests successful

The following utility consolidates logs from the bitcoind nodes and the underlying BitcoinTestFramework:

• /path/to/bitcoin/test/functional/combine_logs.py '/path/to/bitcoin_func_test_XXXXXXX'

6. Custom TestShell parameters

The TestShell object initializes with the default settings inherited from the BitcoinTestFramework class. The user can override these in TestShell.setup(key=value).

Note: TestShell.reset() will reset test parameters to default values and can be called after the TestShell is shut down.

Test parameter key	Default Value	Description
bind_to_localhost_only	True	Binds bitcoind RPC services to 127.0.0.1 if set to True.
cachedir	"/path/to/bitcoin/test/cache"	Sets the bitcoind datadir directory.
chain	"regtest"	Sets the chain-type for the underlying test bitcoind processes.
configfile	"/path/to/bitcoin/test/config.ini"	Sets the location of the test framework config file.
coveragedir	None	Records bitcoind RPC test coverage into this directory if set.
loglevel	INFO	Logs events at this level and higher. Can be set to DEBUG, INFO, WARNING, ERROR or CRITICAL.
nocleanup	False	Cleans up temporary test directory if set to True during shutdown.
noshutdown	False	Does not stop bitcoind instances after shutdown if set to True.
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.
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
trace_rpc	False	Logs all RPC calls if set to True.
usecli	False	Uses the bitcoin-cli interface for all bitcoind commands instead of directly calling the RPC server. Requires supports_cli.