Inject registered cluster name into multi-cluster tests

Depending on the context in which multi-cluster end-to-end tests are
run, there may not be any registered downstream cluster called `second`.
In such cases, such as when testing Fleet in Rancher, the CI workflow
computes the name of the registered cluster and exports it as an
environment variable, for the tests to use instead of `second`.

.github/workflows/e2e-test-fleet-in-rancher.yml

@@ -219,6 +219,9 @@ jobs:
         run: |
           kubectl config use-context k3d-upstream
           ginkgo --github-output e2e/acceptance/single-cluster-examples
+
+          export CI_REGISTERED_CLUSTER=$(kc get clusters.fleet.cattle.io -n $FLEET_E2E_NS_DOWNSTREAM -o jsonpath='{..name}')
+
           ginkgo --github-output e2e/multi-cluster
 
       -

e2e/multi-cluster/not_matching_targets_delete_bd_test.go

@@ -50,7 +50,7 @@ var _ = Describe("Target clusters by label", func() {
 			asset = "multi-cluster/bundle-deployment-labels.yaml"
 			data = TemplateData{env.ClusterRegistrationNamespace, namespace}
 			// set the expected label
-			out, err := k.Namespace(env.ClusterRegistrationNamespace).Label("clusters", "second", "envlabels=test")
+			out, err := k.Namespace(env.ClusterRegistrationNamespace).Label("clusters", dsCluster, "envlabels=test")
 			Expect(err).ToNot(HaveOccurred(), out)
 		})
 
@@ -65,7 +65,7 @@ var _ = Describe("Target clusters by label", func() {
 			}).Should(ContainSubstring("simple-config"))
 
 			// delete the label (bundledeployment should be deleted and resources in cluster deleted)
-			out, err := k.Namespace(env.ClusterRegistrationNamespace).Label("clusters", "second", "envlabels-")
+			out, err := k.Namespace(env.ClusterRegistrationNamespace).Label("clusters", dsCluster, "envlabels-")
 			Expect(err).ToNot(HaveOccurred(), out)
 
 			Eventually(func() string {
@@ -78,7 +78,7 @@ var _ = Describe("Target clusters by label", func() {
 			}).ShouldNot(ContainSubstring("simple-config"))
 
 			// re-apply the label (bundledeployment should be created and applied again)
-			out, err = k.Namespace(env.ClusterRegistrationNamespace).Label("clusters", "second", "envlabels=test")
+			out, err = k.Namespace(env.ClusterRegistrationNamespace).Label("clusters", dsCluster, "envlabels=test")
 			Expect(err).ToNot(HaveOccurred(), out)
 
 			Eventually(func() string {

e2e/multi-cluster/suite_test.go

@@ -2,6 +2,7 @@
 package multicluster_test
 
 import (
+	"os"
 	"testing"
 
 	"github.com/rancher/fleet/e2e/testenv"
@@ -16,12 +17,17 @@ func TestE2E(t *testing.T) {
 }
 
 var (
-	env *testenv.Env
+	env       *testenv.Env
+	dsCluster = "second"
 )
 
 var _ = BeforeSuite(func() {
 	SetDefaultEventuallyTimeout(testenv.Timeout)
 	testenv.SetRoot("../..")
 
 	env = testenv.New()
+
+	if dsClusterEnvVar := os.Getenv("CI_REGISTERED_CLUSTER"); dsClusterEnvVar != "" {
+		dsClusterEnvVar = dsClusterEnvVar
+	}
 })