CASMINST-6936 update readme for running goss tests locally

Signed-off-by: Jacob Salmela <[email protected]>

goss-testing/README.md

@@ -88,6 +88,29 @@ Use the following command to run a single test or a suite of tests on the local
 $ goss -g /opt/cray/tests/install/ncn/tests/[test_file.yaml] --vars /opt/cray/tests/install/ncn/vars/[variable_file.yaml] validate
 ```
 
+## Running All Test Suites Locally
+
+The goss tests can be executed directly (not via the http endpoint) on any node type using a single script.  This will save both a GOSS-formatted JSON file and a DST-compatible JSON file.  
+
+It will run any test that is currently part of a suite connected to a GOSS endpoint on that node.  
+
+It currently runs *all* available suites, sans the LiveCD/PIT tests.  This is used by the CT pipeline to run all tests on a nightly-basis.  Future versions of the script, will allow finer-tuned control.
+
+```bash
+/opt/cray/tests/install/ncn/automated/dst-ct-results.sh
+```
+
+The resulting JSON files can be parsed to get the details.
+
+```shell
+# parse the original goss output for failures
+jq '.results[] | select(.successful == false)' < /tmp/tmp.XbwecrPyr5 # path from stdout after script execution
+
+# parse the dst-compatible file for failures
+jq '.tests[] | select(.status == "fail")' < /tmp/api-results.json # default
+```
+
+
 ## Running Tests Remotely
 
 Use the following command to run a suite of tests on a remote machine where there is a running Goss server endpoint.