DAOS-19886 dlck: make dlck_test_helper suitable for testing

src/utils/dlck/tests/README.md

@@ -0,0 +1,38 @@
+# DLCK Test Helper
+
+Simple utility which takes an existing VOS pool and creates and populates a container inside this pool according to provided parameters.
+
+## Basic usage for MD-on-PMEM pool
+
+`dlck_test_helper` accepts the same parameters as `daos_engine` and `dlck`, for example:
+
+```sh
+./dlck_test_helper --file 102d950b-7cd7-4a02-9ae2-30d08d1f5900,0 --storage /dev/shm/daos
+```
+
+**Note**: To use `dlck_test_helper` against an MD-on-SSD pool provide the `--nvme` parameter.
+
+## Container's contents
+
+Default parameters are hand-picked to produce a small but interesting enough VOS tree for testing purposes, which may look like this:
+
+```
+OID 471378945.1581695481
+├── DKEY 53262252
+│   └── AKEY 3409551c
+├── DKEY 1e81b75f
+│   ├── AKEY 1e81b75f
+│   └── AKEY 53262252 (x2)
+└── DKEY 3409551c
+    └── AKEY 1e81b75f
+OID 1185667690.2136093645
+├── DKEY 53262252
+│   ├── AKEY 3409551c
+│   └── AKEY 1e81b75f
+└── DKEY 17d9b927
+    └── AKEY 17d9b927
+```
+
+**Note**: Since all OIDs and keys are generated randomly and picked at random while generating updates, the effective VOS tree changes when parameters or the implementation change.
+
+You may control the output to some extent by providing extra parameters: `--oids_num`, `--keys_num` and `--updates_num`.

src/utils/dlck/tests/SConscript

@@ -14,6 +14,7 @@ def build_dlck_test_helper(henv):
 
     srcs = [
         'dlck_test_helper.c',
+        'dlck_test_helper_args.c',
         '../dlck_abt.c',
         '../dlck_args_engine.c',
         '../dlck_args_files.c',