Fix type conversion behavior of cluster datasource lifecycle state

This addresses github issue #600

Author: alexng-canuck

CHANGELOG.md

@@ -1,4 +1,8 @@
 ## 3.1.2 (Unreleased)
+
+### Fixed
+- Fixed bug with specifying lifecycle state in container enginge cluster datasource. Issue [#600](https://github.com/terraform-providers/terraform-provider-oci/issues/600)
+
 ## 3.1.1 (September 21, 2018)
 
 ### Fixed

oci/containerengine_cluster_test.go

@@ -193,14 +193,15 @@ variable "cluster_options_add_ons_is_tiller_enabled" { default = true }
 variable "cluster_options_kubernetes_network_config_pods_cidr" { default = "10.1.0.0/16" }
 variable "cluster_options_kubernetes_network_config_services_cidr" { default = "10.2.0.0/16" }
 variable "cluster_options_service_lb_subnet_ids" { default = [] }
-variable "cluster_state" { default = [] }
+variable "cluster_state" { default = ["CREATING", "ACTIVE", FAILED", "DELETING", "DELETED", "UPDATING"] }
 
 data "oci_containerengine_clusters" "test_clusters" {
 	#Required
 	compartment_id = "${var.compartment_id}"
 
 	#Optional
 	name = "${var.cluster_name}"
+	state = "${var.cluster_state}"
 
     filter {
     	name = "id"
@@ -224,6 +225,7 @@ data "oci_containerengine_clusters" "test_clusters" {
 					resource.TestCheckResourceAttr(datasourceName, "clusters.0.options.0.kubernetes_network_config.0.pods_cidr", "10.1.0.0/16"),
 					resource.TestCheckResourceAttr(datasourceName, "clusters.0.options.0.kubernetes_network_config.0.services_cidr", "10.2.0.0/16"),
 					resource.TestCheckResourceAttr(datasourceName, "clusters.0.options.0.service_lb_subnet_ids.#", "2"),
+					resource.TestCheckResourceAttrSet(datasourceName, "clusters.0.state"),
 					resource.TestCheckResourceAttrSet(datasourceName, "clusters.0.vcn_id"),
 				),
 			},

oci/containerengine_clusters_data_source.go

@@ -71,8 +71,8 @@ func (s *ClustersDataSourceCrud) Get() error {
 
 	if states, ok := s.D.GetOkExists("state"); ok {
 		var enumStates []oci_containerengine.ListClustersLifecycleStateEnum
-		for _, r := range states.([]string) {
-			enumStates = append(enumStates, oci_containerengine.ListClustersLifecycleStateEnum(r))
+		for _, r := range states.([]interface{}) {
+			enumStates = append(enumStates, oci_containerengine.ListClustersLifecycleStateEnum(r.(string)))
 		}
 		request.LifecycleState = enumStates
 	}