ea4285775e
c10e382d2a3b76b70ebb8a4eb5cd99fc9f14d702 flatfile: check whether the file has been closed successfully (Vasil Dimov) 4bb5dd78ea4b578922a3316b37b486f96cb0beec util: check that a file has been closed before ~AutoFile() is called (Vasil Dimov) 8bb34f07df9ad45faf25c32c99a4dd70759b25be Explicitly close all AutoFiles that have been written (Vasil Dimov) a69c4098b273b6db5d2212ba91cfc713c1634c5d rpc: take ownership of the file by WriteUTXOSnapshot() (Hodlinator) Pull request description: `fclose(3)` may fail to flush the previously written data to disk, thus a failing `fclose(3)` is as serious as a failing `fwrite(3)`. Previously the code ignored `fclose(3)` failures. This PR improves that by changing all users of `AutoFile` that use it to write data to explicitly close the file and handle a possible error. --- Other alternatives are: 1. `fflush(3)` after each write to the file (and throw if it fails from the `AutoFile::write()` method) and hope that `fclose(3)` will then always succeed. Assert that it succeeds from the destructor 🙄. Will hurt performance. 2. Throw nevertheless from the destructor. Exception within the exception in C++ I think results in terminating the program without a useful message. 3. (this is implemented in the latest incarnation of this PR) Redesign `AutoFile` so that its destructor cannot fail. Adjust _all_ its users 😭. For example, if the file has been written to, then require the callers to explicitly call the `AutoFile::fclose()` method before the object goes out of scope. In the destructor, as a sanity check, assume/assert that this is indeed the case. Defeats the purpose of a RAII wrapper for `FILE*` which automatically closes the file when it goes out of scope and there are a lot of users of `AutoFile`. 4. Pass a new callback function to the `AutoFile` constructor which will be called from the destructor to handle `fclose()` errors, as described in https://github.com/bitcoin/bitcoin/pull/29307#issuecomment-2243842400. My thinking is that if that callback is going to only log a message, then we can log the message directly from the destructor without needing a callback. If the callback is going to do more complicated error handling then it is easier to do that at the call site by directly calling `AutoFile::fclose()` instead of getting the `AutoFile` object out of scope (so that its destructor is called) and inspecting for side effects done by the callback (e.g. set a variable to indicate a failed `fclose()`). ACKs for top commit: l0rinc: ACK c10e382d2a3b76b70ebb8a4eb5cd99fc9f14d702 achow101: ACK c10e382d2a3b76b70ebb8a4eb5cd99fc9f14d702 hodlinator: re-ACK c10e382d2a3b76b70ebb8a4eb5cd99fc9f14d702 Tree-SHA512: 3994ca57e5b2b649fc84f24dad144173b7500fc0e914e06291d5c32fbbf8d2b1f8eae0040abd7a5f16095ddf4e11fe1636c6092f49058cda34f3eb2ee536d7ba
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.
The examples in this document assume the build directory is named
build. You'll need to adapt them if you named it differently.
Compiling/running unit tests
Unit tests will be automatically compiled if dependencies were met during the generation of the Bitcoin Core build system and tests weren't explicitly disabled.
The unit tests can be run with ctest --test-dir build, which includes unit
tests from subtrees.
Run build/bin/test_bitcoin --list_content for the full list of tests.
To run the unit tests manually, launch build/bin/test_bitcoin. To recompile
after a test file was modified, run cmake --build build and then run the test again. If you
modify a non-test file, use cmake --build build --target test_bitcoin 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 build/bin/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
The test_bitcoin runner accepts command line arguments from the Boost
framework. To see the list of arguments that may be passed, run:
build/bin/test_bitcoin --help
For example, to run only the tests in the getarg_tests file, with full logging:
build/bin/test_bitcoin --log_level=all --run_test=getarg_tests
or
build/bin/test_bitcoin -l all -t getarg_tests
or to run only the doubledash test in getarg_tests
build/bin/test_bitcoin --run_test=getarg_tests/doubledash
The --log_level= (or -l) argument controls the verbosity of the test output.
The test_bitcoin runner also accepts some of the command line arguments accepted by
bitcoind. Use -- to separate these sets of arguments:
build/bin/test_bitcoin --log_level=all --run_test=getarg_tests -- -printtoconsole=1
The -printtoconsole=1 after the two dashes sends debug logging, which
normally goes only to debug.log within the data directory, to the
standard terminal output as well.
Running test_bitcoin creates a temporary working (data) directory with a randomly
generated pathname within test_common bitcoin/, which in turn is within
the system's temporary directory (see
temp_directory_path).
This data directory looks like a simplified form of the standard bitcoind data
directory. Its content will vary depending on the test, but it will always
have a debug.log file, for example.
The location of the temporary data directory can be specified with the
-testdatadir option. This can make debugging easier. The directory
path used is the argument path appended with
/test_common bitcoin/<test-name>/datadir.
The directory path is created if necessary.
Specifying this argument also causes the data directory
not to be removed after the last test. This is useful for looking at
what the test wrote to debug.log after it completes, for example.
(The directory is removed at the start of the next test run,
so no leftover state is used.)
$ build/bin/test_bitcoin --run_test=getarg_tests/doubledash -- -testdatadir=/somewhere/mydatadir
Test directory (will not be deleted): "/somewhere/mydatadir/test_common bitcoin/getarg_tests/doubledash/datadir"
Running 1 test case...
*** No errors detected
$ ls -l '/somewhere/mydatadir/test_common bitcoin/getarg_tests/doubledash/datadir'
total 8
drwxrwxr-x 2 admin admin 4096 Nov 27 22:45 blocks
-rw-rw-r-- 1 admin admin 1003 Nov 27 22:45 debug.log
If you run an entire test suite, such as --run_test=getarg_tests, or all the test suites
(by not specifying --run_test), a separate directory
will be created for each individual test.
Adding test cases
To add a new unit test file to our test suite, you need
to add the file to either src/test/CMakeLists.txt or
src/wallet/test/CMakeLists.txt for wallet-related tests. 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
ctest --test-dir build will write to the log file build/Testing/Temporary/LastTest.log. You can
additionally use the --output-on-failure option to display logs of the failed tests automatically
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 build/bin/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 ./build/bin/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 build/bin/test_bitcoin core
(gdb) bt # produce a backtrace for where a segfault occurred