Add tests for parsing NaN, Infinity, and -Infinity

test/parser/nan-inf.jl

@@ -0,0 +1,14 @@
+@testset begin
+    test_str = """{"x": NaN, "y": Infinity, "z": -Infinity}"""
+    @test_throws ErrorException JSON.parse(test_str)
+    val = JSON.parse(test_str, allownan=true)
+    @test val["x"] === NaN
+    @test val["y"] == Inf
+    @test val["z"] == -Inf
+
+    @test_throws ErrorException JSON.parse(IOBuffer(test_str))
+    val2 = JSON.parse(IOBuffer(test_str), allownan=true)
+    @test val2["x"] === NaN
+    @test val2["y"] == Inf
+    @test val2["z"] == -Inf
+end

test/runtests.jl

@@ -25,6 +25,10 @@ include("json-samples.jl")
         include("parser/inttype.jl")
     end
 
+    @testset "nan_inf" begin
+        include("parser/nan-inf.jl")
+    end
+
     @testset "Miscellaneous" begin
         # test for single values
         @test JSON.parse("true") == true