Fix RDF.DateTime to support 24:00:00 as valid time

CHANGELOG.md

@@ -17,6 +17,12 @@ This project adheres to [Semantic Versioning](http://semver.org/) and
   from the XPath and SPARQL specs on `RDF.Boolean`
 
 
+### Fixed
+
+- `RDF.DateTime`: '24:00:00' is a valid time in a xsd:dateTime; the dateTime 
+  value so represented is the first instant of the following day
+
+
 [Compare v0.4.1...HEAD](https://github.com/marcelotto/rdf-ex/compare/v0.4.1...HEAD)
 
 

lib/rdf/datatypes/date_time.ex

@@ -24,6 +24,20 @@ defmodule RDF.DateTime do
           _                -> super(value, opts)
         end
 
+      {:error, :invalid_time} ->
+        if String.contains?(value, "T24:00:00") do
+          with [day, tz]  <- String.split(value, "T24:00:00", parts: 2),
+               {:ok, day} <- Date.from_iso8601(day)
+          do
+            "#{day |> Date.add(1) |> Date.to_string()}T00:00:00#{tz}"
+            |> convert(opts)
+          else
+            _ -> super(value, opts)
+          end
+
+        else
+          super(value, opts)
+        end
       _ ->
         super(value, opts)
     end

test/unit/datatypes/date_time_test.exs

@@ -16,6 +16,8 @@ defmodule RDF.DateTimeTest do
       "2010-01-01T00:00:00+00:00"     => { dt( "2010-01-01T00:00:00Z") , "2010-01-01T00:00:00+00:00", "2010-01-01T00:00:00Z" },
       "2010-01-01T01:00:00+01:00"     => { dt( "2010-01-01T00:00:00Z") , "2010-01-01T01:00:00+01:00", "2010-01-01T00:00:00Z" },
       "2009-12-31T23:00:00-01:00"     => { dt( "2010-01-01T00:00:00Z") , "2009-12-31T23:00:00-01:00", "2010-01-01T00:00:00Z" },
+      "2009-12-31T24:00:00"           => { dt( "2010-01-01T00:00:00")  , "2009-12-31T24:00:00"      , "2010-01-01T00:00:00"  },
+      "2009-12-31T24:00:00+00:00"     => { dt( "2010-01-01T00:00:00Z") , "2009-12-31T24:00:00+00:00", "2010-01-01T00:00:00Z" },
 # TODO: DateTime doesn't support negative years (at least with the iso8601 conversion functions)
 #      "-2010-01-01T00:00:00Z"         => { dt("-2010-01-01T00:00:00Z") , nil, "-2010-01-01T00:00:00Z" },
     },