text: import test from 'ava'
  
  import identifierfy from './'
  
  test('prefixes reserved words with an underscore', t => {
    t.is(identifierfy('class'), '_class')
    t.is(identifierfy('class', { prefixInvalidIdentifiers: false }), '_class')
  })
  
  test('does not prefix reserved words with an underscore, if directed', t => {
    t.is(identifierfy('class', { prefixReservedWords: false }), 'class')
  })
  
  test('prefixes characters that cannot start as an identifier with an underscore', t => {
    t.is(identifierfy('42'), '_42')
    t.is(identifierfy('42', { prefixReservedWords: false }), '_42')
  })
  
  test('does not prefix characters that cannot start as an identifier with an underscore, if directed', t => {
    t.is(identifierfy('42', { prefixInvalidIdentifiers: false }), '42')
  })
  
  test('leaves good names as-is', t => {
    t.is(identifierfy('good'), 'good')
  })
  
  test('drops illegal characters at the front of the name, without uppercasing', t => {
    t.is(identifierfy('-foo'), 'foo')
  })
  
  test('drops illegal characters, uppercasing the character that follows', t => {
    t.is(identifierfy('foo-bar🙊baz'), 'fooBarBaz')
  })
  
  test('not all characters can be upper cased', t => {
    t.is(identifierfy('foo-9'), 'foo9')
  })
  
  test('returns null if no characters from the original name could be used', t => {
    t.is(identifierfy('💩'), null)
  })
  