Seem to be generating JSON correctly and at a good speed too!

src/tests/json/pass_everything.json

@@ -24,7 +24,7 @@
         "ALPHA": "ABCDEFGHIJKLMNOPQRSTUVWYZ",
         "digit": "0123456789",
         "special": "`1~!@#$%^&*()_+-={':[,]}|;.</>?",
-        "hex": "\u0123\u4567\u89AB\uCDEF\uabcd\uef4A",
+        "hex": "\u0123\u4567\u89AB\u0001\uCDEF\uabcd\u001A\uef4A",
         "true": true,
         "false": false,
         "null": null,

src/tests/json/pass_everything.min.json

@@ -0,0 +1 @@
+["JSON Test Pattern pass1",{"object with 1 member":["array with 1 element"]},{},[],-42.0,true,false,null,{"":23456789011999997000000000000000000000000000000000000000000000000000000000000.0," s p a c e d ":[1.0,2.0,3.0,4.0,5.0,6.0,7.0],"# -- --> *\/":" ","\/\\\"쫾몾ꮘﳞ볚\b\f\n\r\t`1~!@#$%^&*()_+-=[]{}|;:',.\/<>?":"A key can be any string","ALPHA":"ABCDEFGHIJKLMNOPQRSTUVWYZ","E":12345678900000000000000000000000000.0,"address":"50 St. James Street","alpha":"abcdefghijklmnopqrstuvwyz","array":[],"backslash":"\\","comment":"\/\/ \/* <!-- --","compact":[1.0,2.0,3.0,4.0,5.0,6.0,7.0],"controls":"\b\f\n\r\t","digit":"0123456789","e":0.000000000000123456789,"false":false,"hex":"ģ䕧覫\u0001췯ꯍ\u001a","integer":1234567890.0,"jsontext":"{\"object with 1 member\":[\"array with 1 element\"]}","null":null,"object":{},"one":1.0,"quote":"\"","quotes":"&#34; \" %22 0x22 034 &#x22;","real":-9876.54321,"slash":"\/ & \/","space":" ","special":"`1~!@#$%^&*()_+-={':[,]}|;.<\/>?","true":true,"url":"http:\/\/www.JSON.org\/","zero":0.0},0.5,98.6,99.44,1066.0,"rosebud"]

src/tests/json/test_json.pl

@@ -1,5 +1,7 @@
-:- module(test_json, [test_json_read/0]).
+:- module(test_json, [test_json_read/0, test_json_minify/0]).
 
+:- use_module(library(charsio)).
+:- use_module(library(dcgs)).
 :- use_module(library(json)).
 :- use_module(library(lists)).
 :- use_module(library(os)).
@@ -25,3 +27,12 @@ test_json_read :-
     name_parse("pass_smallfloat.json", _),
     name_parse("pass_bigfloat.json", _),
     time(name_parse("pass_everything.json", _)).
+
+test_json_minify :-
+    test_path("pass_everything.min.json", MinPath),
+    open(MinPath, read, RefMin),
+    read_line_to_chars(RefMin, RefChars, []),
+    close(RefMin),
+    name_parse("pass_everything.json", Json),
+    time(once(phrase(json_chars(Json), MinChars))),
+    RefChars = MinChars.