If present, top-level domain must be alphabetic

See RFC 1123, Section 2.1
http://tools.ietf.org/html/rfc1123#section-2

1 files changed, 10 insertions, 0 deletions

diff --git a/spec/functions/is_domain_name_spec.rb b/spec/functions/is_domain_name_spec.rb
index 5ab8369..ef88061 100755
--- a/spec/functions/is_domain_name_spec.rb
+++ b/spec/functions/is_domain_name_spec.rb
@@ -68,4 +68,14 @@ describe "the is_domain_name function" do
     result = scope.function_is_domain_name(["my.domain.name".freeze])
     expect(result).to(be_truthy)
   end
+
+  it "should return false if top-level domain is not entirely alphabetic" do
+    result = scope.function_is_domain_name(["kiwi.2bar"])
+    expect(result).to(be_falsey)
+  end
+
+  it "should return false if domain name has the dotted-decimal form, e.g. an IPv4 address" do
+    result = scope.function_is_domain_name(["192.168.1.1"])
+    expect(result).to(be_falsey)
+  end
 end