enha: added unit tests for the domain split (#3)

tests/dns.tftest.hcl

@@ -0,0 +1,53 @@
+provider "aws" {
+  region = "eu-central-1"
+  default_tags {
+    tags = {
+      Environment = "Test"
+    }
+  }
+}
+
+run "base_domain_split_without_sub_domain" {
+  command = plan
+
+  variables {
+    identifier = "abc"
+    domain     = "test.com"
+    zone_id    = "test-zone"
+  }
+
+  assert {
+    condition     = local.base_domain == "test.com"
+    error_message = "Base domain split failed, wanted: 'test.com', got: ${local.base_domain}"
+  }
+}
+
+run "base_domain_split_with_single_sub_domain" {
+  command = plan
+
+  variables {
+    identifier = "abc"
+    domain     = "www.test.com"
+    zone_id    = "test-zone"
+  }
+
+  assert {
+    condition     = local.base_domain == "test.com"
+    error_message = "Base domain split failed, wanted: 'test.com', got: ${local.base_domain}"
+  }
+}
+
+run "base_domain_split_with_multiple_sub_domain" {
+  command = plan
+
+  variables {
+    identifier = "abc"
+    domain     = "www.blog.api.test.com"
+    zone_id    = "test-zone"
+  }
+
+  assert {
+    condition     = local.base_domain == "test.com"
+    error_message = "Base domain split failed, wanted: 'test.com', got: ${local.base_domain}"
+  }
+}