TestApi

Test = {
  new = function(self, title)
    local new = {}
    setmetatable(new, {__index = self})

    self._maxCharsInLine = 50
    self._title = title

    self._printTestTitle(self)

    return new
  end,

  _printTestTitle = function(self)
    self._centerText(self, "-", self._title)
  end,

  _centerText = function(self, centeringChar, text)
    local textSize = string.len(text)
    local centeringStringSize = math.floor((self._maxCharsInLine - textSize)/2)

    for i = 0, centeringStringSize do
      io.write(centeringChar)
    end

    io.write(text)

    for i = 0, centeringStringSize do
      io.write(centeringChar)
    end

    io.write("\n")
  end,

  describe = function(self, description, tests)
    print(description)

    for _, test in pairs(tests) do
      io.write("  ")
      test()
    end
  end,

  it = function(self, testText, testCode)
    return function ()
      local result = function (value)
        return TestResult:new(testText, value)
      end

      testCode(result)
    end
  end
}

TestResult = {
  new = function(self, testText, value)
    local new = {}
    setmetatable(new, {__index = self})
    self.startValue = value
    self.testText = testText
    return new
  end,

  _printResult = function(self, value)
    if value == true then
      io.write("PASSED - ")
    else
      io.write("ERROR  - ")
    end

    io.write("It " .. self.testText .. "\n")
  end,

  isEqual = function(self, value)
    self._printResult(self, self.startValue == value)
  end,

  isNotEqual = function(self, value)
    self._printResult(self, self.startValue ~= value)
  end,

  isLess = function(self, value)
    self._printResult(self, self.startValue < value)
  end,

  isLessOrEqual = function(self, value)
    self._printResult(self, self.startValue <= value)
  end,

  isLarge = function(self, value)
    self._printResult(self, self.startValue > value)
  end,

  isLargeOrEqual = function(self, value)
    self._printResult(self, self.startValue >= value)
  end,

  isTrue = function(self)
    self._printResult(self, self.startValue == true)
  end,

  isFalse = function(self)
    self._printResult(self, self.startValue == false)
  end,

  isNil = function(self)
    self._printResult(self, self.startValue == nil)
  end,

  isNotNil = function(self)
    self._printResult(self, self.startValue ~= nil)
  end,

  throwError = function(self, errorName)
    local status, retval = pcall(self.startValue);

    if status == false then
      retval = self._splitString(self, retval, ": ")[2]
    end

    self._printResult(self, errorName == retval and status == false)
  end,

  _splitString = function(self, s, delimiter)
    local result = {};
    for match in (s..delimiter):gmatch("(.-)"..delimiter) do
        table.insert(result, match);
    end
    return result;
  end
}

return Test