Module: Minitest::Snapshots::Serializer

Defined in:
lib/minitest/snapshots/serializer.rb

Overview

The serializer translates values (objects) into strings. By default, it uses YAML (Psych). Can be overridden to implement custom serialization formats, e.g.:

module Minitest::Snapshots::Serializer
  def self.serialize(value)
    Marshal.dump(value)
  end
end

Constant Summary collapse

HOOK =

The name of the method used to customize the output of to_yaml. Used to provide canonical representations for Hash and Set instances.

:encode_with

Class Method Summary collapse

Class Method Details

.serialize(value) ⇒ Object

Serialize the supplied value to YAML with hooks to canonicalize (i.e. sort) Hash keys and Set elements.

h1 = { foo: "bar", baz: "quux" }
h2 = { baz: "quux", foo: "bar" }

h1.to_yaml == h2.to_yaml                             # => false
Serializer.serialize(h1) == Serializer.serialize(h2) # => true

The hooks are only installed for the duration of the method call and are not installed if custom hooks are already defined.



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# File 'lib/minitest/snapshots/serializer.rb', line 34

def self.serialize(value)
  @lock.synchronize do
    if (hook_hash = hook?(Hash))
      Hash.define_method(HOOK) do |coder|
        sorted = sort_by { |pair| pair.first.to_yaml }.to_h
        coder.map = dup.clear.merge!(sorted)
      end
    end

    if (hook_set = hook?(Set))
      Set.define_method(HOOK) do |coder|
        sorted = sort_by(&:to_yaml)
        coder.seq = dup.clear.merge(sorted)
      end
    end

    value.to_yaml
  ensure
    Hash.remove_method(HOOK) if hook_hash
    Set.remove_method(HOOK) if hook_set
  end
end