Merge pull request #497 from alphagov/warn_about_self_updating_pipelines

Add guidance about disabling acceptance tests

* commit '0a3bbdb56433763cfac9e1a2487fec291e8ca489':
  Add guidance about disabling acceptance tests

README.md

@@ -228,13 +228,15 @@ Acceptance tests can be optionally disabled by setting the environment
 variable `ENABLE_CF_ACCEPTANCE_TESTS=false`.
 
 ```
-ENABLE_CF_ACCEPTANCE_TESTS=false make dev pipelines
+ENABLE_CF_ACCEPTANCE_TESTS=false SELF_UPDATE_PIPELINE=false make dev pipelines
 ```
 
 It is enabled in all the environments except in `staging` and `prod`.
 This will only disable the execution of the test, but the job will
 be still configured in concourse.
 
+*Note:* `SELF_UPDATE_PIPELINE` is also disabled because enabling it would result in the first run immediately enabling the acceptance tests again.
+
 ## Optionally run specific job in the create-bosh-cloudfoundry pipeline
 
 `create-bosh-cloudfoundry` is our main pipeline. When we are making changes or
@@ -407,4 +409,4 @@ Visit [BOSH failover page](https://github.com/alphagov/paas-cf/blob/master/doc/b
 Visit [Pingdom documentation page](https://github.com/alphagov/paas-cf/blob/master/doc/pingdom.md)
 
 ## Other useful commands
-Type `make` to get the list of all available commands.
+Type `make` to get the list of all available commands.