test: doc: Add documentation for ut command

Before adding more options, document this command.

Signed-off-by: Simon Glass <sjg@chromium.org>

doc/usage/cmd/ut.rst

@@ -0,0 +1,102 @@
+.. SPDX-License-Identifier: GPL-2.0+:
+
+ut command
+==========
+
+Synopis
+-------
+
+::
+
+    ut [-r<runs>] [-f] [<suite> [<test>]]
+
+       <runs>      Number of times to run each test
+       -f          Force 'manual' tests to run as well
+       <suite>     Test suite to run, or `all`
+       <test>      Name of single test to run
+
+Description
+-----------
+
+The ut command runs unit tests written in C.
+
+Typically the command is run on :ref:`arch/sandbox/sandbox:sandbox` since it
+includes a near-complete set of emulators, no code-size limits, many CONFIG
+options enabled and runs easily in CI without needing QEMU. It is also possible
+to run some tests on real boards.
+
+For a list of available test suites, type `ut` by itself.
+
+Each test is normally run once, although those marked with `UT_TESTF_DM` are
+run with livetree and flattree where possible. To run a test more than once,
+use the `-r` flag.
+
+Manual tests are normally skipped by this command. Use `-f` to run them. See
+See :ref:`develop/tests_writing:mixing python and c` for more information on
+manual test.
+
+Generally all tests in the suite are run. To run just a single test from the
+suite, provide the <test> argument.
+
+See :ref:`develop/tests_writing:writing c tests` for more information on how to
+write unit tests.
+
+Example
+-------
+
+List available unit-test suites::
+
+    => ut
+    ut - unit tests
+
+    Usage:
+    ut [-r] [-f] [<suite>] - run unit tests
+    -r<runs>   Number of times to run each test
+    -f         Force 'manual' tests to run as well
+    <suite>    Test suite to run, or all
+
+    Suites:
+    all - execute all enabled tests
+    addrmap - very basic test of addrmap command
+    bloblist - bloblist implementation
+    bootstd - standard boot implementation
+    compression - compressors and bootm decompression
+    dm - driver model
+    env - environment
+    fdt - fdt command
+    loadm - loadm command parameters and loading memory blob
+    lib - library functions
+    log - logging functions
+    mem - memory-related commands
+    overlay - device tree overlays
+    print  - printing things to the console
+    setexpr - setexpr command
+    str - basic test of string functions
+    time - very basic test of time functions
+    unicode - Unicode functions
+
+Run one of the suites::
+
+    => ut bloblist
+    Running 14 bloblist tests
+    Test: bloblist_test_align: bloblist.c
+    Test: bloblist_test_bad_blob: bloblist.c
+    Test: bloblist_test_blob: bloblist.c
+    Test: bloblist_test_blob_ensure: bloblist.c
+    Test: bloblist_test_blob_maxsize: bloblist.c
+    Test: bloblist_test_checksum: bloblist.c
+    Test: bloblist_test_cmd_info: bloblist.c
+    Test: bloblist_test_cmd_list: bloblist.c
+    Test: bloblist_test_grow: bloblist.c
+    Test: bloblist_test_init: bloblist.c
+    Test: bloblist_test_reloc: bloblist.c
+    Test: bloblist_test_resize_fail: bloblist.c
+    Test: bloblist_test_resize_last: bloblist.c
+    Test: bloblist_test_shrink: bloblist.c
+    Failures: 0
+
+Run just a single test in a suite::
+
+    => ut bloblist bloblist_test_grow
+    Test: bloblist_test_grow: bloblist.c
+    Failures: 0

doc/usage/index.rst

@@ -74,6 +74,7 @@ Shell commands
    cmd/tftpput
    cmd/true
    cmd/ums
+   cmd/ut
    cmd/wdt
    cmd/xxd