x509ext: test OpenSSL::X509::ExtensionFactory#create_ext with ln

OpenSSL::X509::ExtensionFactory#create_ext and #create_extensions
accepts both sn (short names) and ln (long names) for registered OIDs.

This is different from the behavior of the openssl command-line utility
which accepts only sn in openssl.cnf keys.

Add a test case to check this.

test/openssl/test_x509ext.rb

@@ -70,6 +70,14 @@ def test_create_by_factory
     assert_match(%r{http://cps.example.com}, cp.value)
   end
 
+  def test_factory_create_extension_sn_ln
+    ef = OpenSSL::X509::ExtensionFactory.new
+    bc_sn = ef.create_extension("basicConstraints", "critical, CA:TRUE, pathlen:2")
+    bc_ln = ef.create_extension("X509v3 Basic Constraints", "critical, CA:TRUE, pathlen:2")
+    assert_equal(@basic_constraints.to_der, bc_sn.to_der)
+    assert_equal(@basic_constraints.to_der, bc_ln.to_der)
+  end
+
   def test_dup
     ext = OpenSSL::X509::Extension.new(@basic_constraints.to_der)
     assert_equal(@basic_constraints.to_der, ext.to_der)