case insensitive search in singular AD

Author: varmax2511

examples/networking/vcn/vcn.tf

@@ -24,4 +24,4 @@ resource "oci_core_vcn" "vcn1" {
 
 output "vcn_id" {
   value = "${oci_core_vcn.vcn1.id}"
-}
+}

oci/identity_availability_domain_data_source.go

@@ -127,7 +127,8 @@ func (s *AvailabilityDomainDataSourceCrud) SetData() error {
 }
 
 func adNumberFromName(adName string) int {
-	regex := regexp.MustCompile(`AD-(\d)`)
+	// case insensitive matching
+	regex := regexp.MustCompile(`(?i)AD-(\d)`)
 	res := regex.FindAllStringSubmatch(adName, -1)
 
 	// no matching AD name

oci/identity_availability_domain_test.go

@@ -71,6 +71,21 @@ func TestIdentityAvailabilityDomainResource_basic(t *testing.T) {
 					resource.TestCheckResourceAttrSet(singularDatasourceName, "id"),
 					resource.TestCheckResourceAttr(singularDatasourceName, "ad_number", "2"),
 					resource.TestMatchResourceAttr(singularDatasourceName, "name", regexp.MustCompile(`\w+-AD-2`)),
+					func(s *terraform.State) (err error) {
+						adName, err := fromInstanceState(s, singularDatasourceName, "name")
+						if err != nil {
+							return err
+						}
+
+						regex := regexp.MustCompile(`(?i)AD-(\d)`)
+						res := regex.FindAllStringSubmatch(adName, -1)
+
+						// no matching AD name
+						if res == nil || len(res) < 1 {
+							fmt.Errorf("No match found for case insensitive search")
+						}
+						return err
+					},
 				),
 			},
 		},