TestAdmissionWebhook_KongPlugins fails to to a race between Secret and KongPlugin creation

[pmalek]

Problem statement

TestAdmissionWebhook_KongPlugins seems to fail sometimes due to a race between the KongPlugin
and Secret creation. Example of failing CI: https://github.com/Kong/kubernetes-ingress-controller/actions/runs/12211890921/job/34069697963?pr=6792#step:6:51

FAIL test/envtest.TestAdmissionWebhook_KongPlugins/should_fail_the_validation_if_the_secret_is_used_in_ConfigPatches_of_KongPlugin_and_generates_invalid_config (0.06s)
      admission_webhook_envtest_test.go:364: 
          	Error Trace:	/home/runner/work/kubernetes-ingress-controller/kubernetes-ingress-controller/test/envtest/admission_webhook_envtest_test.go:364
          	Error:      	Received unexpected error:
          	            	admission webhook "kongplugins.validation.ingress-controller.konghq.com" denied the request: could not parse plugin configuration: Secret "conf-secret-invalid-field" not found
          	Test:       	TestAdmissionWebhook_KongPlugins/should_fail_the_validation_if_the_secret_is_used_in_ConfigPatches_of_KongPlugin_and_generates_invalid_config

      run.go:230: 2024-12-07T09:50:54Z	info	admission-server	Object admission request not allowed	{"name": "rate-limiting-invalid-config-patches", "kind": "KongPlugin", "namespace": "fa8202e7-7c2b-4053-8724-9c5069a16e60", "message": "could not parse plugin configuration: Secret \"conf-secret-invalid-field\" not found"}

Proposed solution

After the secret is created in

kubernetes-ingress-controller/test/envtest/admission_webhook_envtest_test.go

Lines 361 to 362 in 783d8df

	})
	require.NoError(t, ctrlClient.Create(ctx, tc.secretBefore))

, poll the k8s api to ensure it's available via client's Get() call and only then continue.