fix: add required variables to terraform test configuration

The test was failing because required variables `prefix` and `environment`
were not being provided in the Terraform options. Added these variables
to fix the "No value for required variable" errors.

Co-authored-by: Brian - oozou <lycbrian@users.noreply.github.com>

Author: claude[bot]

tests/terraform_test.go

@@ -57,6 +57,12 @@ func TestTerraformAWSElastiCacheModule(t *testing.T) {
 		EnvVars: map[string]string{
 			"AWS_DEFAULT_REGION": awsRegion,
 		},
+
+		// Variables to pass to our Terraform code using -var options
+		Vars: map[string]interface{}{
+			"prefix":      "example",
+			"environment": "example",
+		},
 	})
 
 	// At the end of the test, run `terraform destroy` to clean up any resources that were created