test.rb

# -*- coding: utf-8 -*-
require 'voice_text_api'
require 'tempfile'

# https://github.com/tdtds/voice_text_api

vt = VoiceTextAPI.new('YOUR_API_KEY')

# wav = vt.tts('隣の客はよく柿食う客だ', :haruka, emotion: :happiness)
wav = vt.tts('隣の客はよく柿食う客だ', :haruka, emotion: :anger, emotion_level: 2)

Tempfile.open('test-text-api') do |file|
  file.write wav
  system("afplay #{file.path}")
end