Remove upgrade-stable integration test, refactor helm-upgrade

This removes the `upgrade-stable` integration test and refactors the
`helm-upgrade` one to upgrade from the last published edge helm charts
instead of the last stable.

.github/workflows/integration.yml

@@ -312,7 +312,6 @@ jobs:
           - helm-upgrade
           - uninstall
           - upgrade-edge
-          - upgrade-stable
     runs-on: ubuntu-22.04
     timeout-minutes: 15
     steps:

.github/workflows/release.yml

@@ -123,7 +123,6 @@ jobs:
           - helm-upgrade
           - uninstall
           - upgrade-edge
-          - upgrade-stable
     timeout-minutes: 60
     runs-on: ubuntu-22.04
     steps:

bin/_test-helpers.sh

@@ -12,7 +12,7 @@ testdir="$bindir"/../test/integration
 
 ##### Test setup helpers #####
 
-export default_test_names=(deep viz external helm-upgrade uninstall upgrade-edge upgrade-stable default-policy-deny rsa-ca)
+export default_test_names=(deep viz external helm-upgrade uninstall upgrade-edge default-policy-deny rsa-ca)
 export external_resource_test_names=(external-resources)
 export all_test_names=(cluster-domain cni-calico-deep multicluster "${default_test_names[*]}" "${external_resource_test_names[*]}")
 images_load_default=(proxy controller policy-controller web metrics-api tap)
@@ -387,12 +387,6 @@ run_upgrade-edge_test() {
   run_test "$testdir/upgrade-edge/..."
 }
 
-# Run the upgrade-stable test by upgrading the most-recent stable release to the
-# HEAD of this branch.
-run_upgrade-stable_test() {
-  run_test "$testdir/upgrade-stable/..."
-}
-
 run_viz_test() {
   run_test "$testdir/viz/..."
 }
@@ -404,7 +398,7 @@ setup_helm() {
   export helm_release_name='helm-test'
   export helm_multicluster_release_name='multicluster-test'
   "$bindir"/helm-build
-  "$helm_path" --kube-context="$context" repo add linkerd https://helm.linkerd.io/stable
+  "$helm_path" --kube-context="$context" repo add linkerd https://helm.linkerd.io/edge
   exit_on_err 'error setting up Helm'
 }
 
@@ -423,18 +417,18 @@ helm_cleanup() {
 }
 
 run_helm-upgrade_test() {
-  local stable_version
-  stable_version=$(latest_release_channel 'stable')
+  local edge_version
+  edge_version=$(latest_release_channel 'edge')
 
-  if [ -z "$stable_version" ]; then
-    echo 'error getting stable_version'
+  if [ -z "$edge_version" ]; then
+    echo 'error getting edge_version'
     exit 1
   fi
 
   setup_helm
   helm_viz_chart="$( cd "$bindir"/.. && pwd )"/viz/charts/linkerd-viz
   run_test "$testdir/install/install_test.go" --helm-path="$helm_path" --helm-charts="$helm_charts" \
-  --viz-helm-chart="$helm_viz_chart" --viz-helm-stable-chart="linkerd/linkerd-viz" --helm-release="$helm_release_name" --upgrade-helm-from-version="$stable_version"
+  --viz-helm-chart="$helm_viz_chart" --viz-helm-stable-chart="linkerd/linkerd-viz" --helm-release="$helm_release_name" --upgrade-helm-from-version="$edge_version"
   helm_cleanup
 }