Crystal JSON vs YAML serialization

crystal_json_vs_yaml_serialization.cr

require "json"
require "yaml"
require "secure_random"

class SerializableKlass
  YAML.mapping({
    bool:  { type: Bool,    nilable: true},
    float: { type: Float64, nilable: true},
    int:   { type: Int32,   nilable: true},
    str:   { type: String,  nilable: true}
  })

  JSON.mapping({
    bool:  { type: Bool,    nilable: true},
    float: { type: Float64, nilable: true},
    int:   { type: Int32,   nilable: true},
    str:   { type: String,  nilable: true}
  })

  RANDOM = Random.new

  macro add_to_yml(property)
    unless {{property}}.nil?
      yaml.nl
      yaml << "{{property}}: #{@{{property}}}"
    end
  end

  def initialize(bool  : (Bool    | Nil) = [RANDOM.next_bool,  nil].sample,
                 str   : (String  | Nil) = [SecureRandom.hex,  nil].sample,
                 float : (Float64 | Nil) = [RANDOM.next_float, nil].sample,
                 int   : (Int32   | Nil) = [RANDOM.next_int,   nil].sample)
    @bool  = bool
    @str   = str
    @float = float
    @int   = int
  end

  def to_yaml(yaml : YAML::Generator)
    yaml.indented do
      add_to_yml(bool)
      add_to_yml(str)
      add_to_yml(float)
      add_to_yml(int)
    end
  end

  def ==(other)
    return false unless other.is_a?(SerializableKlass)
    other.bool  == bool  && \
    other.str   == str   && \
    other.float == float && \
    other.int   == int
  end
end

require "spec"

describe SerializableKlass do
  it "can be serialized to/from JSON" do
    42.times do
      object = SerializableKlass.new
      SerializableKlass.from_json(object.to_json).should eq(object)
    end
  end

  it "can be serialized to/from YAML" do
    42.times do
      object = SerializableKlass.new
      SerializableKlass.from_yaml(object.to_yaml).should eq(object)
    end
  end
end

JSON spec show a float serialization problem and YAML parse fail :-/

> crystal run crystal_json_vs_yaml_serialization.cr
FE

Failures:

  1) SerializableKlass can be serialized to/from JSON
     Failure/Error: SerializableKlass.from_json(object.to_json).should eq(object)

       expected: #<SerializableKlass:0x1ec2280 @bool=nil, @float=0.49257630703332284, @int=nil, @str="df694f7df279d1a4c0231f9ece0e6379">
            got: #<SerializableKlass:0x1ec21e0 @bool=nil, @float=0.49257630703332289, @int=nil, @str="df694f7df279d1a4c0231f9ece0e6379">

     # ./crystal_json_vs_yaml_serialization.cr:63

  2) SerializableKlass can be serialized to/from YAML

       expected MAPPING_START but was SCALAR at 1:0
       [4596631] *CallStack::unwind:Array(Pointer(Void)) +87
       [4596522] *CallStack#initialize:Array(Pointer(Void)) +10
       [4596474] *CallStack::new:CallStack +42
       [4572456] *raise<YAML::ParseException>:NoReturn +24
       [5017962] ???
       [5018424] *YAML::PullParser#expect_kind<LibYAML::EventType>:Nil +136
       [5018266] *YAML::PullParser#read<LibYAML::EventType>:LibYAML::EventType +10
       [5018459] *YAML::PullParser#read_mapping_start:LibYAML::EventType +11
       [4972229] *SerializableKlass#initialize<YAML::PullParser>:(String | Nil) +197
       [4972001] *SerializableKlass::new<YAML::PullParser>:SerializableKlass +129
       [4971803] *SerializableKlass +75
       [4572351] ~procProc(Nil) +79
       [4570245] *it<String, String, Int32, &Proc(Nil)>:(Array(Spec::Result) | Nil) +469
       [4569758] ~procProc(Nil) +126
       [4819383] *Spec::RootContext::describe<String, String, Int32, &Proc(Nil)>:Spec::Context+ +391
       [4569575] *describe<SerializableKlass:Class, String, Int32, &Proc(Nil)>:Spec::Context+ +55
       [4505376] ???
       [4562585] main +41
       [140125722131269] __libc_start_main +245
       [4501561] ???
       [0] ???

Finished in 380 microseconds
2 examples, 1 failures, 1 errors, 0 pending

Failed examples:

crystal spec ./crystal_json_vs_yaml_serialization.cr:60 # SerializableKlass can be serialized to/from JSON
crystal spec ./crystal_json_vs_yaml_serialization.cr:67 # SerializableKlass can be serialized to/from YAML