Handle corner-case on canonicalizing a Double whose value is nil. (to_sxp issues).

Author: gkellogg

lib/rdf/model/literal/double.rb

@@ -43,6 +43,7 @@ def canonicalize!
       # Can't use simple %f transformation due to special requirements from
       # N3 tests in representation
       @string = case
+        when @object.nil?      then 'NaN'
         when @object.nan?      then 'NaN'
         when @object.infinite? then @object.to_s[0...-'inity'.length].upcase
         when @object.zero?     then '0.0E0'

spec/model_literal_spec.rb

@@ -615,8 +615,8 @@ def self.literals(*selector)
       %w(-INF      -INF),
       %w(+INF      INF),
       #%w(NaN       NaN),
-      #%w(NAN        NaN),
-      %w(InF        INF),
+      #%w(NAN       NaN),
+      %w(InF       INF),
       %w(3E1       3.0E1)
     ]
     it_behaves_like 'RDF::Literal validation', RDF::XSD.double,
@@ -641,7 +641,7 @@ def self.literals(*selector)
         1.0       => ["1.0", "1.0E0"],
         0.0       => ["0.0", "0.0E0"],
         10.10     => ["10.1", "1.01E1"],
-        123.456e4 => ["1234560.0", "1.23456E6"],
+        123.456e4 => ["1234560.0", "1.23456E6"]
       }.each do |obj, (str, canon)|
         it "to_str #{obj} to #{str.inspect}" do
           expect(RDF::Literal::Double.new(obj).to_s).to eql str