document variable controlled debug loop

.forgejo/workflows/integration.yml

@@ -9,10 +9,10 @@ jobs:
           - version: "1.21.0-2-rc0"
             image: codeberg.org/forgejo-experimental/forgejo
             # keep "cron" last otherwise it will linger and pollute the following runs
-            tests: "${{ vars.V121_TESTS || 'echo artifacts service checkout pull-request container expression local-action docker-action if if-fail cron' }}"
+            tests: "${{ vars.V1_21_TESTS || 'echo push-cancel artifacts service checkout pull-request container expression local-action docker-action if if-fail cron' }}"
           - version: "1.20"
             image: codeberg.org/forgejo/forgejo
-            tests: "${{ vars.V120_TESTS || 'echo checkout service container expression local-action docker-action if if-fail' }}"
+            tests: "${{ vars.V1_20_TESTS || 'echo checkout service container expression local-action docker-action if if-fail' }}"
     steps:
       - uses: actions/checkout@v3
       - if: matrix.info.tests != 'none'

README.md

@@ -86,9 +86,13 @@ jobs:
 
 ## Hacking
 
-* Update the README from the action file with https://github.com/npalm/action-docs `action-docs --update-readme`
+### Documentation
 
-To manually run and debug workflows from `testdata/example-*`, from
+Update the README from the action file with https://github.com/npalm/action-docs `action-docs --update-readme`
+
+### Local testing
+
+To run and debug workflows from `testdata/example-*`, from
 the root of the source directory, with docker and forgejo-curl.sh
 installed, mimic what `.forgejo/workflows/integration.yml` does. There
 may be some manual tweaking (such as creating temporary directories)
@@ -105,3 +109,14 @@ because the tests run as root, but they do not need to run as root.
 * `forgejo-test-helper.sh run_workflow testdata/example-$example http://root:admin1234@$(cat forgejo-ip):3000 root example-$example setup-forgejo $(cat forgejo-token)`
 * `forgejo-runner.sh teardown`
 * `forgejo.sh teardown`
+
+### Remote testing
+
+To reduce the runtime the following variables can be set to control
+the number of cases run by the
+[integration](.forgejo/workflows/integration.yml) tests. If set to
+**none** they are not run at all for that version of Forgejo. If
+it does not exist, all tests are run.
+
+* `V1_21_TESTS`
+* `V1_20_TESTS`