f60b9059e4
CConnman then passes the current best height into CNode at creation time. This way CConnman/CNode have no dependency on main for height, and the signals only move in one direction. This also helps to prevent identity leakage a tiny bit. Before this change, an attacker could theoretically make 2 connections on different interfaces. They would connect fully on one, and only establish the initial connection on the other. Once they receive a new block, they would relay it to your first connection, and immediately commence the version handshake on the second. Since the new block height is reflected immediately, they could attempt to learn whether the two connections were correlated. This is, of course, incredibly unlikely to work due to the small timings involved and receipt from other senders. But it doesn't hurt to lock-in nBestHeight at the time of connection, rather than letting the remote choose the time.
Notes
The sources in this directory are unit test cases. Boost includes a unit testing framework, and since bitcoin 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 setup to compile an executable called test_bitcoin
that runs all of the unit tests. The main source file is called
test_bitcoin.cpp. 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,
examine uint256_tests.cpp.
For further reading, I found the following website to be helpful in explaining how the boost unit test framework works: http://www.alittlemadness.com/2009/03/31/c-unit-testing-with-boosttest/.
test_bitcoin has some built-in command-line arguments; for example, to run just the getarg_tests verbosely:
test_bitcoin --log_level=all --run_test=getarg_tests
... or to run just the doubledash test:
test_bitcoin --run_test=getarg_tests/doubledash
Run test_bitcoin --help for the full list.