text: const  StructuredSource = require('structured-source');
  
  let src = new StructuredSource('aaa\u2028aaaa\u2029aaaaa\n');
  
  // positionToIndex({ line: number, column: number) -> number
  assert(src.positionToIndex({ line: 1, column: 2 }) === 2);
  
  // indexToPosition(number) -> { line: number, column: number }
  assert.deepEqual(src.indexToPosition(2), { line: 1, column: 2 });
  
  // rangeToLocation([ number, number ]) -> { start: { line: number, column: number}, end: { line: number, column: number } }
  assert.deepEqual(src.rangeToLocation([0, 2]), {
      start: { line: 1, column: 0 },
      end: { line: 1, column: 2 }
  });
  
  // locationToRange({ start: { line: number, column: number}, end: { line: number, column: number } }) -> [ number, number ]
  assert.deepEqual(src.locationToRange({
      start: { line: 1, column: 0 },
      end: { line: 1, column: 2 }
  }), [0, 2]);
  