zstd/tests/cli-tests

CLI tests

The CLI tests are focused on testing the zstd CLI. They are intended to be simple tests that the CLI and arguments work as advertised. They are not intended to test the library, only the code in programs/. The library will get incidental coverage, but if you find yourself trying to trigger a specific condition in the library, this is the wrong tool.

Test runner usage

The test runner run.py will run tests against the in-tree build of zstd and datagen by default. Which means that zstd and datagen must be built.

The zstd binary used can be passed with --zstd /path/to/zstd. Additionally, to run zstd through a tool like valgrind or qemu, set the --exec-prefix 'valgrind -q' flag.

Similarly, the --datagen, and --zstdgrep flags can be set to specify the paths to their respective binaries. However, these tools do not use the EXEC_PREFIX.

Each test executes in its own scratch directory under scratch/test/name. E.g. scratch/basic/help.sh/. Normally these directories are removed after the test executes. However, the --preserve flag will preserve these directories after execution, and save the tests exit code, stdout, and stderr in the scratch directory to exit, stderr, and stdout respectively. This can be useful for debugging/editing a test and updating the expected output.

Running all the tests

By default the test runner run.py will run all the tests, and report the results.

Examples:

./run.py
./run.py --preserve
./run.py --zstd ../../build/programs/zstd --datagen ../../build/tests/datagen

Running specific tests

A set of test names can be passed to the test runner run.py to only execute those tests. This can be useful for writing or debugging a test, especially with --preserve.

The test name can either be the path to the test file, or the test name, which is the path relative to the test directory.

Examples:

./run.py basic/help.sh
./run.py --preserve basic/help.sh basic/version.sh
./run.py --preserve --verbose basic/help.sh

Writing a test

Test cases are arbitrary executables, and can be written in any language, but are generally shell scripts. After the script executes, the exit code, stderr, and stdout are compared against the expectations.

Each test is run in a clean directory that the test can use for intermediate files. This directory will be cleaned up at the end of the test, unless --preserve is passed to the test runner. Additionally, the setup script can prepare the directory before the test runs.

Calling zstd, utilities, and environment variables

The $PATH for tests is prepended with the bin/ sub-directory, which contains helper scripts for ease of testing. The zstd binary will call the zstd binary specified by run.py with the correct $EXEC_PREFIX. Similarly, datagen, unzstd, zstdgrep, zstdcat, etc, are provided.

Helper utilities like cmp_size, println, and die are provided here too. See their scripts for details.

Common shell script libraries are provided under common/, with helper variables and functions. They can be sourced with source "$COMMON/library.sh.

Lastly, environment variables are provided for testing, which can be listed when calling run.py with --verbose. They are generally used by the helper scripts in bin/ to coordinate everything.

Basic test case

When executing your $TEST executable, by default the exit code is expected to be 0. However, you can provide an alternate expected exit code in a $TEST.exit file.

When executing your $TEST executable, by default the expected stderr and stdout are empty. However, you can override the default by providing one of three files:

• $TEST.{stdout,stderr}.exact
• $TEST.{stdout,stderr}.glob
• $TEST.{stdout,stderr}.ignore

If you provide a .exact file, the output is expected to exactly match, byte-for-byte.

If you provide a .glob file, the output is expected to match the expected file, where each line is interpreted as a glob syntax. Additionally, a line containing only ... matches all lines until the next expected line matches.

If you provide a .ignore file, the output is ignored.

Passing examples

All these examples pass.

Exit 1, and change the expectation to be 1.

exit-1.sh
---
#!/bin/sh
exit 1
---

exit-1.sh.exit
---
1
---

Check the stdout output exactly matches.

echo.sh
---
#!/bin/sh
echo "hello world"
---

echo.sh.stdout.exact
---
hello world
---

Check the stderr output using a glob.

random.sh
---
#!/bin/sh
head -c 10 < /dev/urandom | xxd >&2
---

random.sh.stderr.glob
---
00000000: * * * * *                 *

Multiple lines can be matched with ...

random-num-lines.sh
---
#!/bin/sh
echo hello
seq 0 $RANDOM
echo world
---

random-num-lines.sh.stdout.glob
---
hello
0
...
world
---

Failing examples

Exit code is expected to be 0, but is 1.

exit-1.sh
---
#!/bin/sh
exit 1
---

Stdout is expected to be empty, but isn't.

echo.sh
---
#!/bin/sh
echo hello world

Stderr is expected to be hello but is world.

hello.sh
---
#!/bin/sh
echo world >&2
---

hello.sh.stderr.exact
---
hello
---

Setup & teardown scripts

Finally, test writing can be eased with setup and teardown scripts. Each directory in the test directory is a test-suite consisting of all tests within that directory (but not sub-directories). This test suite can come with 4 scripts to help test writing:

• setup_once
• teardown_once
• setup
• teardown

The setup_once and teardown_once are run once before and after all the tests in the suite respectively. They operate in the scratch directory for the test suite, which is the parent directory of each scratch directory for each test case. They can do work that is shared between tests to improve test efficiency. For example, the dictionaries/setup_once script builds several dictionaries, for use in the dictionaries tests.

The setup and teardown scripts run before and after each test case respectively, in the test case's scratch directory. These scripts can do work that is shared between test cases to make tests more succinct. For example, the dictionaries/setup script copies the dictionaries built by the dictionaries/setup_once script into the test's scratch directory, to make them easier to use, and make sure they aren't accidentally modified.

Examples

basic/setup
---
#!/bin/sh
# Create some files for testing with
datagen > file
datagen > file0
datagen > file1
---

basic/test.sh
---
#!/bin/sh
zstd file file0 file1
---

dictionaries/setup_once
---
#!/bin/sh
set -e

mkdir files/ dicts/
for i in $(seq 10); do
	datagen -g1000 > files/$i
done

zstd --train -r files/ -o dicts/0
---

dictionaries/setup
---
#!/bin/sh

# Runs in the test case's scratch directory.
# The test suite's scratch directory that
# `setup_once` operates in is the parent directory.
cp -r ../files ../dicts .
---