Add cli-tests framework

Add a framework for writing automated tests of the fscrypt command-line
tool.  See cli-tests/README.md for details.

1 files changed, 67 insertions, 0 deletions

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+# fscrypt command-line interface tests
+
+## Usage
+
+To run the command-line interface (CLI) tests for `fscrypt`, ensure
+that your kernel is v5.4 or later and has `CONFIG_FS_ENCRYPTION=y`.
+Also ensure that you have the following packages installed:
+
+* e2fsprogs
+* expect
+* keyutils
+
+Then, run:
+
+```shell
+make cli-test
+```
+
+You'll need to enter your `sudo` password, as the tests require root.
+
+If you only want to run specific tests, run a command like:
+
+```shell
+make && sudo cli-tests/run.sh t_encrypt t_unlock
+```
+
+## Updating the expected output
+
+When the output of `fscrypt` has intentionally changed, the test
+`.out` files need to be updated.  This can be done automatically by
+the following command, but be sure to review the changes:
+
+```shell
+make cli-test-update
+```
+
+## Writing CLI tests
+
+The fscrypt CLI tests are `bash` scripts named like `t_*.sh`.
+
+The test scripts must be executable and begin by sourcing `common.sh`.
+They all run in bash "extra-strict mode" (`-e -u -o pipefail`).  They
+run as root and have access to the following environment:
+
+* `$DEV`, `$DEV_ROOT`: ext4 filesystem images with encryption enabled
+
+* `$MNT`, `$MNT_ROOT`: the mountpoints of the above filesystems.
+  Initially all filesystems are mounted and are setup for fscrypt.
+  Login protectors will be stored on `$MNT_ROOT`.
+
+* `$TMPDIR`: a temporary directory that the test may use
+
+* `$FSCRYPT_CONF`: location of the fscrypt.conf file.  Initially this
+  file exists and specifies to use v2 policies with the default
+  settings, except password hashing is configured to be extra fast.
+
+* `$TEST_USER`: a non-root user that the test may use.  Their password
+  is `TEST_USER_PASS`.
+
+Any output (stdout and stderr) the test prints is compared to the
+corresponding `.out` file.  If a difference is detected then the test
+is considered to have failed.  The output is first sent through some
+standard filters; see `run.sh`.
+
+The test is also failed if it exits with nonzero status.
+
+See `common.sh` for utility functions the tests may use.