Fail upgrade tests when test script fails

Prior to this commit, if any lines in the upgrade testing script
that didn't have special error handling failed, the script would
continue to run, making it very hard to debug.

This commit fails the script if any lines fail, and doesn't prevent
lines with special error handling (i.e. `fail_test`) from performing
their own cleanup steps.

In addition, prior to this commit, lines deleting Tekton CRDs
were run after the pipelines webhook and CRD definitions were deleted.
This commit moves deletion of resources to happen before Tekton is
uninstalled, so deletion can happen successfully.

Lastly, this commit handles cases where the variable PIPELINE_FEATURE_GATE
is not set, and causes the script to fail if any unbound variables
are referenced.

test/e2e-common.sh

@@ -113,7 +113,7 @@ function patch_pipeline_spire() {
 
 function verify_pipeline_installation() {
   # Make sure that everything is cleaned up in the current namespace.
-  delete_pipeline_resources
+  delete_tekton_resources
 
   # Wait for pods to be running in the namespaces we are deploying to
   wait_until_pods_running tekton-pipelines || fail_test "Tekton Pipeline did not come up"
@@ -143,25 +143,20 @@ function verify_log_access_enabled() {
 function uninstall_pipeline_crd() {
   echo ">> Uninstalling Tekton Pipelines"
   ko delete --ignore-not-found=true -R -f config/
-
-  # Make sure that everything is cleaned up in the current namespace.
-  delete_pipeline_resources
 }
 
 function uninstall_pipeline_crd_version() {
   echo ">> Uninstalling Tekton Pipelines of version $1"
   kubectl delete --ignore-not-found=true -f "https://github.com/tektoncd/pipeline/releases/download/$1/release.yaml"
 
-  if [ "${PIPELINE_FEATURE_GATE}" == "alpha" ]; then
+  if [ -v ${PIPELINE_FEATURE_GATE+x} && "${PIPELINE_FEATURE_GATE}" == "alpha" ]; then
     kubectl delete --ignore-not-found=true -f "https://github.com/tektoncd/pipeline/releases/download/$1/resolvers.yaml"
   fi
-
-  # Make sure that everything is cleaned up in the current namespace.
-  delete_pipeline_resources
 }
 
-function delete_pipeline_resources() {
+function delete_tekton_resources() {
   for res in tasks clustertasks pipelines taskruns pipelineruns; do
+    echo ">> Deleting ${res}"
     kubectl delete --ignore-not-found=true ${res}.tekton.dev --all
   done
 }

test/e2e-tests-upgrade.sh

@@ -37,9 +37,10 @@ fi
 
 header "Setting up environment"
 
-# Handle failures ourselves, so we can dump useful info.
-set +o errexit
-set +o pipefail
+# Exit if any failures occur or any unbound variables are referenced
+set -o errexit
+set -o pipefail
+set -o nounset
 
 # First, we will verify if Scenario 1 works.
 # Install the previous release.
@@ -58,6 +59,7 @@ go_test_e2e -timeout=20m ./test || failed=1
 go_test_e2e -tags=examples -timeout=20m ./test/ || failed=1
 
 # Remove all the pipeline CRDs, and clean up the environment for next Scenario.
+delete_tekton_resources
 uninstall_pipeline_crd
 uninstall_pipeline_crd_version $PREVIOUS_PIPELINE_VERSION