local conjecture = require('collatz-conjecture')

describe('collatz-conjecture', function()
  it('zero steps for one', function()
    assert.are.equal(0, conjecture(1))
  end)

  it('divide if even', function()
    assert.are.equal(4, conjecture(16))
  end)

  it('even and odd steps', function()
    assert.are.equal(9, conjecture(12))
  end)

  it('large number of even and odd steps', function()
    assert.are.equal(152, conjecture(1000000))
  end)

  it('zero is an error', function()
    assert.has_error(
      function() conjecture(0) end,
      'Only positive numbers are allowed'
    )
  end)

  it('negative value is an error', function()
    assert.has_error(
      function() conjecture(-15) end,
      'Only positive numbers are allowed'
    )
  end)
end)