If there is an existing cloud project, we want to delete it to prevent collisions. If there isn't one this command would fail, so we use ucm:error. But we have to add in a dummy failure to satisfy ucm:error in the case that the project does exist and thus the delete.project is successful.
scratch/main> delete.project cloud
scratch/main> forceBlockToFail
cloud/main> pull.without-history @unison/cloud/${CLOUD_CLIENT_VERSION}
cloud/main> test
cloud/main> io.test tests.cloud.runAllLocally
cloud/main> io.test tests.cloud.runAll