laanwj 6300b9556e
Merge bitcoin/bitcoin#24357: refactor: make setsockopt() and SetSocketNoDelay() mockable/testable
a2c4a7acd1dfb2fb7e3c9dac6b3d8c9354b2e0a6 net: use Sock::SetSockOpt() instead of standalone SetSocketNoDelay() (Vasil Dimov)
d65b6c3fb9cdd41fa53bc76a7b8f49aaa089b0bc net: use Sock::SetSockOpt() instead of setsockopt() (Vasil Dimov)
184e56d6683d05fc84f5153cfff83a2e32883556 net: add new method Sock::SetSockOpt() that wraps setsockopt() (Vasil Dimov)

Pull request description:

  _This is a piece of #21878, chopped off to ease review._

  Add a `virtual` (thus mockable) method `Sock::SetSockOpt()` that wraps the system `setsockopt()`.

  Convert the standalone `SetSocketNoDelay()` function to a `virtual` (thus mockable) method `Sock::SetNoDelay()`.

  This will help avoid syscalls during testing and to mock them to return whatever is suitable for the tests.

ACKs for top commit:
  laanwj:
    Code review ACK a2c4a7acd1dfb2fb7e3c9dac6b3d8c9354b2e0a6
  jonatack:
    ACK a2c4a7acd1dfb2fb7e3c9dac6b3d8c9354b2e0a6 change since last review is folding `Sock::SetNoDelay()` into the callers

Tree-SHA512: 3e2b016c1e4128317a28c17dc9b30472949e1ac3b071b2697c6d30cbcc830df1ee4392a4e23b2ea1ab4e3fb0f59ef450e2a4f3c1df3d8c803dd081652b6c7387
2022-04-19 16:43:47 +02:00
..
2021-11-01 14:20:56 +01:00

Unit tests

The sources in this directory are unit test cases. Boost includes a unit testing framework, and since Bitcoin Core already uses Boost, it makes sense to simply use this framework rather than require developers to configure some other framework (we want as few impediments to creating unit tests as possible).

The build system is set up to compile an executable called test_bitcoin that runs all of the unit tests. The main source file for the test library is found in util/setup_common.cpp.

Compiling/running unit tests

Unit tests will be automatically compiled if dependencies were met in ./configure and tests weren't explicitly disabled.

After configuring, they can be run with make check.

To run the unit tests manually, launch src/test/test_bitcoin. To recompile after a test file was modified, run make and then run the test again. If you modify a non-test file, use make -C src/test to recompile only what's needed to run the unit tests.

To add more unit tests, add BOOST_AUTO_TEST_CASE functions to the existing .cpp files in the test/ directory or add new .cpp files that implement new BOOST_AUTO_TEST_SUITE sections.

To run the GUI unit tests manually, launch src/qt/test/test_bitcoin-qt

To add more GUI unit tests, add them to the src/qt/test/ directory and the src/qt/test/test_main.cpp file.

Running individual tests

test_bitcoin accepts the command line arguments from the boost framework. For example, to run just the getarg_tests suite of tests:

test_bitcoin --log_level=all --run_test=getarg_tests

log_level controls the verbosity of the test framework, which logs when a test case is entered, for example. test_bitcoin also accepts the command line arguments accepted by bitcoind. Use -- to separate both types of arguments:

test_bitcoin --log_level=all --run_test=getarg_tests -- -printtoconsole=1

The -printtoconsole=1 after the two dashes redirects the debug log, which would normally go to a file in the test datadir (BasicTestingSetup::m_path_root), to the standard terminal output.

... or to run just the doubledash test:

test_bitcoin --run_test=getarg_tests/doubledash

Run test_bitcoin --help for the full list.

Adding test cases

To add a new unit test file to our test suite you need to add the file to src/Makefile.test.include. The pattern is to create one test file for each class or source file for which you want to create unit tests. The file naming convention is <source_filename>_tests.cpp and such files should wrap their tests in a test suite called <source_filename>_tests. For an example of this pattern, see uint256_tests.cpp.

Logging and debugging in unit tests

make check will write to a log file foo_tests.cpp.log and display this file on failure. For running individual tests verbosely, refer to the section above.

To write to logs from unit tests you need to use specific message methods provided by Boost. The simplest is BOOST_TEST_MESSAGE.

For debugging you can launch the test_bitcoin executable with gdb or lldb and start debugging, just like you would with any other program:

gdb src/test/test_bitcoin

Segmentation faults

If you hit a segmentation fault during a test run, you can diagnose where the fault is happening by running gdb ./src/test/test_bitcoin and then using the bt command within gdb.

Another tool that can be used to resolve segmentation faults is valgrind.

If for whatever reason you want to produce a core dump file for this fault, you can do that as well. By default, the boost test runner will intercept system errors and not produce a core file. To bypass this, add --catch_system_errors=no to the test_bitcoin arguments and ensure that your ulimits are set properly (e.g. ulimit -c unlimited).

Running the tests and hitting a segmentation fault should now produce a file called core (on Linux platforms, the file name will likely depend on the contents of /proc/sys/kernel/core_pattern).

You can then explore the core dump using

gdb src/test/test_bitcoin core

(gbd) bt  # produce a backtrace for where a segfault occurred