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Testing

Introduction

Libraries need pervasive testing for continuous improvement. Any problem found and behavior described must be written down as test so that it is assured that no new regressions will be added.

Running Tests

Running all tests in the build directory:

make run_all

And on the target (installed) system:

kdb run_all

To run memcheck tests run in the build directory:

make run_memcheck

They are supplementary, ideally you run all three.

Some tests write into system paths and into the home directory. This implies that the UID running the tests must have a home directory. To avoid running tests that write to the disk you can use:

make run_nokdbtests

You can also directly run ctest to make use of parallel testing:

ctest -T Test --output-on-failure -j 6
ctest -T MemCheck -LE memleak --output-on-failure -j 6

The alternative to make run_nokdbtests:

ctest -T Test --output-on-failure -LE kdbtests -j 6

To only run tests whose names match a regular expression, you can use:

ctest -V -R <regex>

Required Environment

To run the tests successfully, the environment must fulfill:

  • Mounted /dev and /proc (to have stdin and stdout for import & export test cases).
  • POSIX tools need to be available (including the file tool)
  • User must be able to write to system and spec (see below)

If the access is denied, several tests will fail. You have some options to avoid running them as root:

  1. To avoid running the problematic test cases (reduces the test coverage!) run ctest without tests that have the label kdbtests: ctest --output-on-failure -LE kdbtests (which is also what make run_nokdbtests does)

  2. To give your user the permissions to the relevant paths execute the lines below once as root.

    Warning: Changing permissions on the wrong paths can be harmful! Please make sure that the paths are correct. In doubt make sure that you have a backup of the affected directories.

    First load the required information and verify the paths:

    sudo kdb mount-info
echo `kdb sget system:/info/elektra/constants/cmake/CMAKE_INSTALL_PREFIX .`/`kdb sget system:/info/elektra/constants/cmake/KDB_DB_SPEC .`
echo `kdb sget system:/info/elektra/constants/cmake/KDB_DB_SYSTEM .`

    Then change the permissions:

    sudo chown -R `whoami` `kdb sget system:/info/elektra/constants/cmake/CMAKE_INSTALL_PREFIX .`/`kdb sget system:/info/elektra/constants/cmake/KDB_DB_SPEC .`
sudo chown -R `whoami` `kdb sget system:/info/elektra/constants/cmake/KDB_DB_SYSTEM .`

    After that all test cases should run successfully as described above.

  3. Compile Elektra so that system paths are not actual system paths, e.g. to write everything into the home directory (~) use cmake options: -DKDB_DB_SYSTEM="~/.config/kdb/system" -DKDB_DB_SPEC="~/.config/kdb/spec" (for an example of a full CMake invocation see scripts/configure-home)

  4. Use the XDG resolver (see scripts/configure-xdg) and set the environment variable XDG_CONFIG_DIRS, currently lacks spec namespaces, see #734.

Manual Testing

Running executables in the build directory needs some preparation. Here we assume that build is the build directory and it is the top-level of Elektra's source code:

cd build
. ../scripts/dev/run_env

After sourcing run_env, you can directly execute kdb and other binaries built with Elektra (such as the examples).

Pay attention that sourcing depends on the operating system or rather the shell. For example on standard FreeBSD 11.3 you have to execute sh in the root of the repository first. Then do not use the source command but the point . as explained above.

Using debuggers

You can use debuggers such as gdb to develop Elektra. This can be interesting if you write test cases and they fail at some unknown point. Many tests are put into the /bin folder in your build directory. As a consequence, you can cd into /bin and call, for example

gdb hello

If you use Docker to run your tests it makes sense to call the debugger in the same container. In this case you might be required to pass additional parameters to Docker. An example for this is passing --security-opt seccomp=unconfined to disable address space randomization.

Recommended Environment

The tests are designed to disable themselves if some necessary tools are missing or other environmental constraints are not met. To really run all tests (also those that are mostly designed for internal development) you need to fulfil:

  • Elektra must be installed (for gen + external test cases).
  • A running dbus daemon (Either "system" or "session" daemon).
  • gpg2 or gpg binary must be available.

Above environment is needed for both kdb run_all (installed test cases) and make run_all (test cases executed from the build directory). For make run_all following development tools enable even more tests:

You can also use Docker to set up such an environment. There is a tutorial that guides you through the necessary steps.

Adding Tests

For plugins, adding ADD_TEST to add_plugin will execute the tests in testmod_${pluginname}.c. This is done by default for newly generated plugins.

Add CPP_TEST if the test is written in C++. Then testmod_${pluginname}.cpp will be used. These tests use the gtest test framework.

If the tests should not always be executed, the CMake function add_plugintest can be used instead. See cmake/Modules/LibAddPlugin.cmake for more information.

By using TEST_README in add_plugin (also enabled by default), Markdown Shell Recorder are expected to be in the README.md of the plugin.

Conventions

  • All names of the test must start with test (needed by test driver for installed tests).

  • No tests should run if ENABLE_TESTING is OFF.

  • All tests that access system/spec namespaces (e.g. mount something):

  • should be tagged with kdbtests:

    set_property(TEST testname PROPERTY LABELS kdbtests)

  • should not run, if ENABLE_KDB_TESTING is OFF.

  • should only write below

    • /tests/<testname> (e.g. /tests/ruby) and
    • system:/elektra (e.g. for mounts or globalplugins).

  • Before executing tests, no keys must be present below /tests. The test cases need to clean up everything they wrote. (Including temporary files)

  • If your test has memory leaks, e.g. because the library used leaks and they cannot be fixed, give them the label memleak with the following command:

    set_property(TEST testname PROPERTY LABELS memleak)

  • If your test modifies resources needed by other tests you also need to set RUN_SERIAL:

    set_property(TEST testname PROPERTY RUN_SERIAL TRUE)

Strategy

The testing must happen on every level of the software to achieve a maximum coverage with the available time. In the rest of the document we describe the different levels and where these tests are.

CFramework

This is basically a bunch of assertion macros and some output facilities. It is written in pure C and very lightweight.

It is located here.

ABI Tests

C ABI Tests are written in plain C with the help of cframework.

The main purpose of these tests are, that the binaries of old versions can be used against new versions as ABI tests.

So lets say we compile Elektra 0.8.8 (at this version dedicated ABI tests were introduced) in the -full variant. But when we run the tests, we use libelektra-full.so.0.8.9 (either by installing it or by setting LD_LIBRARY_PATH). You can check with ldd which version is used.

The tests are located here.

C Unit Tests

C Unit Tests are written in plain C with the help of cframework.

It is used to test internal data structures of libelektra that are not ABI relevant.

ABI tests can be done on theses tests, too. But by nature from time to time these tests will fail.

They are located here.

Internal Functions

According to src/libs/elektra/libelektra-symbols.map, all functions starting with:

  • libelektra
  • elektra
  • kdb
  • key
  • ks

get exported. Functions not starting with this prefix are internal only and therefore not visible in the test cases. Test internal functionality by including the corresponding C file.

Module Tests

The modules, which are typically used as plugins in Elektra (but can also be available statically or in the -full variant), should have their own tests.

Use the CMake macro add_plugintest for adding these tests.

C++ Unit Tests

C++ Unit tests are done using the Google Test framework. See architectural decision.

Use the CMake macro add_gtest for adding these tests.

Script Tests

Tests which need scripts are done using shell recorder or directly with POSIX shell commands. See architectural decision.

The script tests have different purposes:

  • End to End tests (usage of tools as an end user would do)
  • External compilation tests (compile and run programs as a user would do)
  • Conventions tests (do internal checks that check for common problems)
  • Meta Test Suites (run other test suites)

See here.

Shell Recorder

The more elegant way to specify script tests are via the so called Shell Recorder using Markdown Syntax.

See here.

Fuzz Testing

We assume that your current working directory is a newly created build directory. First compile Elektra with afl (~e is source-dir of Elektra):

~e/scripts/dev/configure-debian -DCMAKE_C_COMPILER=/usr/src/afl/AFL-2.57b/afl-gcc -DCMAKE_CXX_COMPILER=/usr/src/afl/AFL-2.57b/afl-g++ ~e
make -j 5

Copy some import files to testcase_dir, for example:

mkdir -p testcase_dir
cp ~e/src/plugins/toml/toml/* testcase_dir

Fewer files is better. Then run, for example:

LD_LIBRARY_PATH=`pwd`/lib /usr/src/afl/AFL-2.57b/afl-fuzz -i testcase_dir -o findings_dir bin/kdb import user:/tests toml

Check if something is happening with:

watch kdb export user:/tests

ASAN

To enable sanitize checks use ENABLE_ASAN via cmake.

Then, to use ASAN, run run_asan in the build directory, which simply does:

ASAN_OPTIONS=symbolize=1 ASAN_SYMBOLIZER_PATH=$(which llvm-symbolizer) make run_all

It could also happen that you need to preload ASAN library, e.g.:

LD_PRELOAD=/usr/lib/clang/3.8.0/lib/linux/libclang_rt.asan-x86_64.so run_asan

or on Debian:

LD_PRELOAD=/usr/lib/llvm-3.8/lib/clang/3.8.1/lib/linux/libclang_rt.asan-x86_64.so run_asan

macOS

If you use macOS you might want to use the clang versions provided by Homebrew, since it supports the LeakSanitizer. To use Homebrew’s version of clang you need to first install LLVM:

brew install llvm

. After that change the CC and CXX environment variables to point to the the clang tools provided by LLVM:

export CC=/usr/local/opt/llvm/bin/clang
export CXX=/usr/local/opt/llvm/bin/clang++

. Now run CMake and build Elektra just like you normally would. To enable the Leak Sanitizer you need to also set the variable ASAN_OPTIONS before you run a test:

export ASAN_OPTIONS=detect_leaks=1

.

CBMC

For bounded model checking tests, see scripts/cbmc.

Static Code Checkers

There is a number of static code checkers available for all kind of programming languages. The following section show how the most common ones can be used with libelektra.

Cppcheck

Cppcheck can be used directly on a C or C++ source file by calling it with cppcheck --enable=all <sourcefile>. This way it might miss some header files though and thus doesn't detect all possible issues, but still gives useful hints in general.

To analyze the whole project, use it in conjunction with cmake by calling cmake with the parameter -DCMAKE_EXPORT_COMPILE_COMMANDS=ON. This way cmake creates a file called compile_commands.json in the build directory. Afterwards, call cppcheck with the cmake settings and store the output as xml:

cppcheck --project=compile_commands.json --enable=all -j 8 --xml-version=2 2> cppcheck_result.xml

Since the XML file is difficult to read directly, the best way is to convert it to an HTML report. Cppcheck already includes a tool for that, call it with the XML report:

cppcheck-htmlreport --file=cppcheck_result.xml --report-dir=cppcheck_report --source-dir=.

Now you can view the html report by opening index.html in the specified folder to get an overview of the issues found in the whole project.

OCLint

OCLint is a static code analyzer for C, C++ and Objective C. To use this tool enable the CMake option CMAKE_EXPORT_COMPILE_COMMANDS. The steps below show a step-by-step guide on how to analyze files with OCLint.

  1. Create a build directory if you have not done so already and change the working path to this directory:

    mkdir -p build
cd build

  2. Run CMake with the option CMAKE_EXPORT_COMPILE_COMMANDS:

    cmake .. -DCMAKE_EXPORT_COMPILE_COMMANDS=ON

  3. Build Elektra

    make

  4. Run the oclint command specifying the files you want to analyze

    cd ..
oclint -p build -no-analytics -enable-global-analysis -enable-clang-static-analyzer src/plugins/toml/*.c

scan-build

scan-build is a tool that is usually bundled along with LLVM/Clang and is also primarily intended for C and C++ code. On macOS you have to install the package llvm with homebrew, then you'll find the tool in the folder /usr/local/opt/llvm/bin/.

To use it, change the C compiler and the C++ compiler to the LLVM analyzer. To do this, you can configure the project from scratch and prefix the cmake command with scan-build. Alternatively, set the c compiler to ccc-analyzer and the C++ compiler to c++-analyzer (bundled with LLVM/Clang).

Then you can build the project with make like usual, prefixing the command with scan-build. The -o option specifies where the html results get stored. Ensure you build the project from scratch, otherwise the analyzation might be incomplete.

scan-build -o ./scanbuild_result make -j 4

Afterwards, the report can be viewed by using the tool scan-view, also found in the llvm folder. The report is created in the folder specified above, along with the current date of the analyzation, for instance:

scan-view <path specified above>/2017-06-18-171027-27108-1

Alternatively, you can also open the index.html file in the aforementioned folder, but using the tool the report is enriched with further information.

SonarLint

SonarLint is a static code checker primarily intended for Java. It is usually used by installing the corresponding plugin for the used IDE, then there is no further configuration required.

Randoop

For using the unit test generator randoop with the jna bindings, see scripts/randoop/randoop.

Code Coverage

Run:

make coverage-start
# now run all tests! E.g.:
make run_all
make coverage-stop
make coverage-genhtml

The HTML files can be found in the build directory in the folder coverage.

See Also