parseSpec.js

'use strict';

// This file has many tests which read nicely if constant conditions
// are used.
/* eslint-disable no-constant-condition */

describe('parser', function() {

  describe('lexer', function() {
    var lex;

    beforeEach(function() {
      /* global Lexer: false */
      lex = function() {
        var lexer = new Lexer({csp: false});
        return lexer.lex.apply(lexer, arguments);
      };
    });

    it('should only match number chars with isNumber', function() {
      expect(Lexer.prototype.isNumber('0')).toBe(true);
      expect(Lexer.prototype.isNumber('')).toBeFalsy();
      expect(Lexer.prototype.isNumber(' ')).toBeFalsy();
      expect(Lexer.prototype.isNumber(0)).toBeFalsy();
      expect(Lexer.prototype.isNumber(false)).toBeFalsy();
      expect(Lexer.prototype.isNumber(true)).toBeFalsy();
      expect(Lexer.prototype.isNumber(undefined)).toBeFalsy();
      expect(Lexer.prototype.isNumber(null)).toBeFalsy();
    });

    it('should tokenize a string', function() {
      var tokens = lex('a.bc[22]+1.3|f:\'a\\\'c\':"d\\"e"');
      var i = 0;
      expect(tokens[i].index).toEqual(0);
      expect(tokens[i].text).toEqual('a');

      i++;
      expect(tokens[i].index).toEqual(1);
      expect(tokens[i].text).toEqual('.');

      i++;
      expect(tokens[i].index).toEqual(2);
      expect(tokens[i].text).toEqual('bc');

      i++;
      expect(tokens[i].index).toEqual(4);
      expect(tokens[i].text).toEqual('[');

      i++;
      expect(tokens[i].index).toEqual(5);
      expect(tokens[i].text).toEqual('22');
      expect(tokens[i].value).toEqual(22);
      expect(tokens[i].constant).toEqual(true);

      i++;
      expect(tokens[i].index).toEqual(7);
      expect(tokens[i].text).toEqual(']');

      i++;
      expect(tokens[i].index).toEqual(8);
      expect(tokens[i].text).toEqual('+');

      i++;
      expect(tokens[i].index).toEqual(9);
      expect(tokens[i].text).toEqual('1.3');
      expect(tokens[i].value).toEqual(1.3);
      expect(tokens[i].constant).toEqual(true);

      i++;
      expect(tokens[i].index).toEqual(12);
      expect(tokens[i].text).toEqual('|');

      i++;
      expect(tokens[i].index).toEqual(13);
      expect(tokens[i].text).toEqual('f');

      i++;
      expect(tokens[i].index).toEqual(14);
      expect(tokens[i].text).toEqual(':');

      i++;
      expect(tokens[i].index).toEqual(15);
      expect(tokens[i].value).toEqual('a\'c');

      i++;
      expect(tokens[i].index).toEqual(21);
      expect(tokens[i].text).toEqual(':');

      i++;
      expect(tokens[i].index).toEqual(22);
      expect(tokens[i].value).toEqual('d"e');
    });

    it('should tokenize identifiers with spaces around dots the same as without spaces', function() {
      function getText(t) { return t.text; }
      var spaces = lex('foo. bar . baz').map(getText);
      var noSpaces = lex('foo.bar.baz').map(getText);

      expect(spaces).toEqual(noSpaces);
    });

    it('should use callback functions to know when an identifier is valid', function() {
      function getText(t) { return t.text; }
      var isIdentifierStart = jasmine.createSpy('start');
      var isIdentifierContinue = jasmine.createSpy('continue');
      isIdentifierStart.and.returnValue(true);
      var lex = new Lexer({csp: false, isIdentifierStart: isIdentifierStart, isIdentifierContinue: isIdentifierContinue});

      isIdentifierContinue.and.returnValue(true);
      var tokens = lex.lex('πΣε').map(getText);
      expect(tokens).toEqual(['πΣε']);

      isIdentifierContinue.and.returnValue(false);
      tokens = lex.lex('πΣε').map(getText);
      expect(tokens).toEqual(['π', 'Σ', 'ε']);
    });

    it('should send the unicode characters and code points', function() {
      function getText(t) { return t.text; }
      var isIdentifierStart = jasmine.createSpy('start');
      var isIdentifierContinue = jasmine.createSpy('continue');
      isIdentifierStart.and.returnValue(true);
      isIdentifierContinue.and.returnValue(true);
      var lex = new Lexer({csp: false, isIdentifierStart: isIdentifierStart, isIdentifierContinue: isIdentifierContinue});
      var tokens = lex.lex('\uD801\uDC37\uD852\uDF62\uDBFF\uDFFF');
      expect(isIdentifierStart).toHaveBeenCalledTimes(1);
      expect(isIdentifierStart.calls.argsFor(0)).toEqual(['\uD801\uDC37', 0x10437]);
      expect(isIdentifierContinue).toHaveBeenCalledTimes(2);
      expect(isIdentifierContinue.calls.argsFor(0)).toEqual(['\uD852\uDF62', 0x24B62]);
      expect(isIdentifierContinue.calls.argsFor(1)).toEqual(['\uDBFF\uDFFF', 0x10FFFF]);
    });

    it('should tokenize undefined', function() {
      var tokens = lex('undefined');
      var i = 0;
      expect(tokens[i].index).toEqual(0);
      expect(tokens[i].text).toEqual('undefined');
    });

    it('should tokenize quoted string', function() {
      var str = '[\'\\\'\', "\\""]';
      var tokens = lex(str);

      expect(tokens[1].index).toEqual(1);
      expect(tokens[1].value).toEqual('\'');

      expect(tokens[3].index).toEqual(7);
      expect(tokens[3].value).toEqual('"');
    });

    it('should tokenize escaped quoted string', function() {
      var str = '"\\"\\n\\f\\r\\t\\v\\u00A0"';
      var tokens = lex(str);

      expect(tokens[0].value).toEqual('"\n\f\r\t\v\u00A0');
    });

    it('should tokenize unicode', function() {
      var tokens = lex('"\\u00A0"');
      expect(tokens.length).toEqual(1);
      expect(tokens[0].value).toEqual('\u00a0');
    });

    it('should ignore whitespace', function() {
      var tokens = lex('a \t \n \r b');
      expect(tokens[0].text).toEqual('a');
      expect(tokens[1].text).toEqual('b');
    });

    it('should tokenize relation and equality', function() {
      var tokens = lex('! == != < > <= >= === !==');
      expect(tokens[0].text).toEqual('!');
      expect(tokens[1].text).toEqual('==');
      expect(tokens[2].text).toEqual('!=');
      expect(tokens[3].text).toEqual('<');
      expect(tokens[4].text).toEqual('>');
      expect(tokens[5].text).toEqual('<=');
      expect(tokens[6].text).toEqual('>=');
      expect(tokens[7].text).toEqual('===');
      expect(tokens[8].text).toEqual('!==');
    });

    it('should tokenize logical and ternary', function() {
      var tokens = lex('&& || ? :');
      expect(tokens[0].text).toEqual('&&');
      expect(tokens[1].text).toEqual('||');
      expect(tokens[2].text).toEqual('?');
      expect(tokens[3].text).toEqual(':');
    });

    it('should tokenize statements', function() {
      var tokens = lex('a;b;');
      expect(tokens[0].text).toEqual('a');
      expect(tokens[1].text).toEqual(';');
      expect(tokens[2].text).toEqual('b');
      expect(tokens[3].text).toEqual(';');
    });

    it('should tokenize function invocation', function() {
      var tokens = lex('a()');
      expect(tokens.map(function(t) { return t.text;})).toEqual(['a', '(', ')']);
    });

    it('should tokenize method invocation', function() {
      var tokens = lex('a.b.c (d) - e.f()');
      expect(tokens.map(function(t) { return t.text;})).
          toEqual(['a', '.', 'b', '.', 'c',  '(', 'd', ')', '-', 'e', '.', 'f', '(', ')']);
    });

    it('should tokenize number', function() {
      var tokens = lex('0.5');
      expect(tokens[0].value).toEqual(0.5);
    });

    it('should tokenize negative number', inject(function($rootScope) {
      var value = $rootScope.$eval('-0.5');
      expect(value).toEqual(-0.5);

      value = $rootScope.$eval('{a:-0.5}');
      expect(value).toEqual({a:-0.5});
    }));

    it('should tokenize number with exponent', inject(function($rootScope) {
      var tokens = lex('0.5E-10');
      expect(tokens[0].value).toEqual(0.5E-10);
      expect($rootScope.$eval('0.5E-10')).toEqual(0.5E-10);

      tokens = lex('0.5E+10');
      expect(tokens[0].value).toEqual(0.5E+10);
    }));

    it('should throws exception for invalid exponent', function() {
      expect(function() {
        lex('0.5E-');
      }).toThrowMinErr('$parse', 'lexerr', 'Lexer Error: Invalid exponent at column 4 in expression [0.5E-].');

      expect(function() {
        lex('0.5E-A');
      }).toThrowMinErr('$parse', 'lexerr', 'Lexer Error: Invalid exponent at column 4 in expression [0.5E-A].');
    });

    it('should tokenize number starting with a dot', function() {
      var tokens = lex('.5');
      expect(tokens[0].value).toEqual(0.5);
    });

    it('should throw error on invalid unicode', function() {
      expect(function() {
        lex('\'\\u1\'\'bla\'');
      }).toThrowMinErr('$parse', 'lexerr', 'Lexer Error: Invalid unicode escape [\\u1\'\'b] at column 2 in expression [\'\\u1\'\'bla\'].');
    });
  });

  describe('ast', function() {
    var createAst;

    beforeEach(function() {
      /* global AST: false */
      createAst = function() {
        var lexer = new Lexer({csp: false});
        var ast = new AST(lexer, {csp: false, literals: {'true': true, 'false': false, 'undefined': undefined, 'null': null}});
        return ast.ast.apply(ast, arguments);
      };
    });

    it('should handle an empty list of tokens', function() {
      expect(createAst('')).toEqual({type: 'Program', body: []});
    });


    it('should understand identifiers', function() {
      expect(createAst('foo')).toEqual(
        {
          type: 'Program',
          body: [
            {
              type: 'ExpressionStatement',
              expression: { type: 'Identifier', name: 'foo' }
            }
          ]
        }
      );
    });


    it('should understand non-computed member expressions', function() {
      expect(createAst('foo.bar')).toEqual(
        {
          type: 'Program',
          body: [
            {
              type: 'ExpressionStatement',
              expression: {
                type: 'MemberExpression',
                object: { type: 'Identifier', name: 'foo'},
                property: {type: 'Identifier', name: 'bar'},
                computed: false
              }
            }
          ]
        }
      );
    });


    it('should associate non-computed member expressions left-to-right', function() {
      expect(createAst('foo.bar.baz')).toEqual(
        {
          type: 'Program',
          body: [
            {
              type: 'ExpressionStatement',
              expression: {
                type: 'MemberExpression',
                object: {
                  type: 'MemberExpression',
                  object: { type: 'Identifier', name: 'foo'},
                  property: { type: 'Identifier', name: 'bar' },
                  computed: false
                },
                property: {type: 'Identifier', name: 'baz'},
                computed: false
              }
            }
          ]
        }
      );
    });


    it('should understand computed member expressions', function() {
      expect(createAst('foo[bar]')).toEqual(
        {
          type: 'Program',
          body: [
            {
              type: 'ExpressionStatement',
              expression: {
                type: 'MemberExpression',
                object: { type: 'Identifier', name: 'foo'},
                property: {type: 'Identifier', name: 'bar'},
                computed: true
              }
            }
          ]
        }
      );
    });


    it('should associate computed member expressions left-to-right', function() {
      expect(createAst('foo[bar][baz]')).toEqual(
        {
          type: 'Program',
          body: [
            {
              type: 'ExpressionStatement',
              expression: {
                type: 'MemberExpression',
                object: {
                  type: 'MemberExpression',
                    object: { type: 'Identifier', name: 'foo' },
                    property: { type: 'Identifier', name: 'bar' },
                  computed: true
                },
                property: { type: 'Identifier', name: 'baz' },
                computed: true
              }
            }
          ]
        }
      );
    });


    it('should understand call expressions', function() {
      expect(createAst('foo()')).toEqual(
        {
          type: 'Program',
          body: [
            {
              type: 'ExpressionStatement',
              expression: {
                type: 'CallExpression',
                callee: { type: 'Identifier', name: 'foo'},
                arguments: []
              }
            }
          ]
        }
      );
    });


    it('should parse call expression arguments', function() {
      expect(createAst('foo(bar, baz)')).toEqual(
        {
          type: 'Program',
          body: [
            {
              type: 'ExpressionStatement',
              expression: {
                type: 'CallExpression',
                callee: { type: 'Identifier', name: 'foo'},
                arguments: [
                  { type: 'Identifier', name: 'bar' },
                  { type: 'Identifier', name: 'baz' }
                ]
              }
            }
          ]
        }
      );
    });


    it('should parse call expression left-to-right', function() {
      expect(createAst('foo(bar, baz)(man, shell)')).toEqual(
        {
          type: 'Program',
          body: [
            {
              type: 'ExpressionStatement',
              expression: {
                type: 'CallExpression',
                callee: {
                  type: 'CallExpression',
                  callee: { type: 'Identifier', name: 'foo' },
                  arguments: [
                    { type: 'Identifier', name: 'bar' },
                    { type: 'Identifier', name: 'baz' }
                  ]
                },
                arguments: [
                  { type: 'Identifier', name: 'man' },
                  { type: 'Identifier', name: 'shell' }
                ]
              }
            }
          ]
        }
      );
    });


    it('should keep the context when having superfluous parenthesis', function() {
      expect(createAst('(foo)(bar, baz)')).toEqual(
        {
          type: 'Program',
          body: [
            {
              type: 'ExpressionStatement',
              expression: {
                type: 'CallExpression',
                callee: { type: 'Identifier', name: 'foo'},
                arguments: [
                  { type: 'Identifier', name: 'bar' },
                  { type: 'Identifier', name: 'baz' }
                ]
              }
            }
          ]
        }
      );
    });


    it('should treat member expressions and call expression with the same precedence', function() {
      expect(createAst('foo.bar[baz]()')).toEqual(
        {
          type: 'Program',
          body: [
            {
              type: 'ExpressionStatement',
              expression: {
                type: 'CallExpression',
                callee: {
                  type: 'MemberExpression',
                  object: {
                    type: 'MemberExpression',
                    object: { type: 'Identifier', name: 'foo' },
                    property: { type: 'Identifier', name: 'bar' },
                    computed: false
                  },
                  property: { type: 'Identifier', name: 'baz' },
                  computed: true
                },
                arguments: []
              }
            }
          ]
        }
      );
      expect(createAst('foo[bar]().baz')).toEqual(
        {
          type: 'Program',
          body: [
            {
              type: 'ExpressionStatement',
              expression: {
                type: 'MemberExpression',
                object: {
                  type: 'CallExpression',
                  callee: {
                    type: 'MemberExpression',
                    object: { type: 'Identifier', name: 'foo' },
                    property: { type: 'Identifier', name: 'bar' },
                    computed: true
                  },
                  arguments: []
                },
                property: { type: 'Identifier', name: 'baz' },
                computed: false
              }
            }
          ]
        }
      );
      expect(createAst('foo().bar[baz]')).toEqual(
        {
          type: 'Program',
          body: [
            {
              type: 'ExpressionStatement',
              expression: {
                type: 'MemberExpression',
                object: {
                  type: 'MemberExpression',
                  object: {
                    type: 'CallExpression',
                    callee: { type: 'Identifier', name: 'foo' },
                    arguments: [] },
                  property: { type: 'Identifier', name: 'bar' },
                  computed: false
                },
                property: { type: 'Identifier', name: 'baz' },
                computed: true
              }
            }
          ]
        }
      );
    });


    it('should understand literals', function() {
      // In a strict sense, `undefined` is not a literal but an identifier
      forEach({'123': 123, '"123"': '123', 'true': true, 'false': false, 'null': null, 'undefined': undefined}, function(value, expression) {
        expect(createAst(expression)).toEqual(
          {
            type: 'Program',
            body: [
              {
                type: 'ExpressionStatement',
                expression: { type: 'Literal', value: value }
              }
            ]
          }
        );
      });
    });


    it('should understand the `this` expression', function() {
      expect(createAst('this')).toEqual(
        {
          type: 'Program',
          body: [
            {
              type: 'ExpressionStatement',
              expression: { type: 'ThisExpression' }
            }
          ]
        }
      );
    });


    it('should understand the `$locals` expression', function() {
      expect(createAst('$locals')).toEqual(
        {
          type: 'Program',
          body: [
            {
              type: 'ExpressionStatement',
              expression: { type: 'LocalsExpression' }
            }
          ]
        }
      );
    });


    it('should not confuse `this`, `$locals`, `undefined`, `true`, `false`, `null` when used as identifiers', function() {
      forEach(['this', '$locals', 'undefined', 'true', 'false', 'null'], function(identifier) {
        expect(createAst('foo.' + identifier)).toEqual(
          {
            type: 'Program',
            body: [
              {
                type: 'ExpressionStatement',
                expression: {
                  type: 'MemberExpression',
                  object: { type: 'Identifier', name: 'foo' },
                  property: { type: 'Identifier', name: identifier },
                  computed: false
                }
              }
            ]
          }
        );
      });
    });


    it('should throw when trying to use non-identifiers as identifiers', function() {
      expect(function() { createAst('foo.)'); }).toThrowMinErr('$parse', 'syntax',
          'Syntax Error: Token \')\' is not a valid identifier at column 5 of the expression [foo.)');
    });


    it('should throw when all tokens are not consumed', function() {
      expect(function() { createAst('foo bar'); }).toThrowMinErr('$parse', 'syntax',
          'Syntax Error: Token \'bar\' is an unexpected token at column 5 of the expression [foo bar] starting at [bar]');
    });


    it('should understand the unary operators `-`, `+` and `!`', function() {
      forEach(['-', '+', '!'], function(operator) {
        expect(createAst(operator + 'foo')).toEqual(
          {
            type: 'Program',
            body: [
              {
                type: 'ExpressionStatement',
                expression: {
                  type: 'UnaryExpression',
                  operator: operator,
                  prefix: true,
                  argument: { type: 'Identifier', name: 'foo' }
                }
              }
            ]
          }
        );
      });
    });


    it('should handle all unary operators with the same precedence', function() {
      forEach([['+', '-', '!'], ['-', '!', '+'], ['!', '+', '-']], function(operators) {
        expect(createAst(operators.join('') + 'foo')).toEqual(
          {
            type: 'Program',
            body: [
              {
                type: 'ExpressionStatement',
                expression: {
                  type: 'UnaryExpression',
                  operator: operators[0],
                  prefix: true,
                  argument: {
                    type: 'UnaryExpression',
                    operator: operators[1],
                    prefix: true,
                    argument: {
                      type: 'UnaryExpression',
                      operator: operators[2],
                      prefix: true,
                      argument: { type: 'Identifier', name: 'foo' }
                    }
                  }
                }
              }
            ]
          }
        );
      });
    });


    it('should be able to understand binary operators', function() {
      forEach(['*', '/', '%', '+', '-', '<', '>', '<=', '>=', '==','!=','===','!=='], function(operator) {
        expect(createAst('foo' + operator + 'bar')).toEqual(
          {
            type: 'Program',
            body: [
              {
                type: 'ExpressionStatement',
                expression: {
                  type: 'BinaryExpression',
                  operator: operator,
                  left: { type: 'Identifier', name: 'foo' },
                  right: { type: 'Identifier', name: 'bar' }
                }
              }
            ]
          }
        );
      });
    });


    it('should associate binary operators with the same precedence left-to-right', function() {
      var operatorsByPrecedence = [['*', '/', '%'], ['+', '-'], ['<', '>', '<=', '>='], ['==','!=','===','!==']];
      forEach(operatorsByPrecedence, function(operators) {
        forEach(operators, function(op1) {
          forEach(operators, function(op2) {
            expect(createAst('foo' + op1 + 'bar' + op2 + 'baz')).toEqual(
              {
                type: 'Program',
                body: [
                  {
                    type: 'ExpressionStatement',
                    expression: {
                      type: 'BinaryExpression',
                      operator: op2,
                      left: {
                        type: 'BinaryExpression',
                        operator: op1,
                        left: { type: 'Identifier', name: 'foo' },
                        right: { type: 'Identifier', name: 'bar' }
                      },
                      right: { type: 'Identifier', name: 'baz' }
                    }
                  }
                ]
              }
            );
          });
        });
      });
    });


    it('should give higher precedence to member calls than to unary expressions', function() {
      forEach(['!', '+', '-'], function(operator) {
        expect(createAst(operator + 'foo()')).toEqual(
          {
            type: 'Program',
            body: [
              {
                type: 'ExpressionStatement',
                expression: {
                  type: 'UnaryExpression',
                  operator: operator,
                  prefix: true,
                  argument: {
                    type: 'CallExpression',
                    callee: { type: 'Identifier', name: 'foo' },
                    arguments: []
                  }
                }
              }
            ]
          }
        );
        expect(createAst(operator + 'foo.bar')).toEqual(
          {
            type: 'Program',
            body: [
              {
                type: 'ExpressionStatement',
                expression: {
                  type: 'UnaryExpression',
                  operator: operator,
                  prefix: true,
                  argument: {
                    type: 'MemberExpression',
                    object: { type: 'Identifier', name: 'foo' },
                    property: { type: 'Identifier', name: 'bar' },
                    computed: false
                  }
                }
              }
            ]
          }
        );
        expect(createAst(operator + 'foo[bar]')).toEqual(
          {
            type: 'Program',
            body: [
              {
                type: 'ExpressionStatement',
                expression: {
                  type: 'UnaryExpression',
                  operator: operator,
                  prefix: true,
                  argument: {
                    type: 'MemberExpression',
                    object: { type: 'Identifier', name: 'foo' },
                    property: { type: 'Identifier', name: 'bar' },
                    computed: true
                  }
                }
              }
            ]
          }
        );
      });
    });


    it('should give higher precedence to unary operators over multiplicative operators', function() {
      forEach(['!', '+', '-'], function(op1) {
        forEach(['*', '/', '%'], function(op2) {
          expect(createAst(op1 + 'foo' + op2 + op1 + 'bar')).toEqual(
            {
              type: 'Program',
              body: [
                {
                  type: 'ExpressionStatement',
                  expression: {
                    type: 'BinaryExpression',
                    operator: op2,
                    left: {
                      type: 'UnaryExpression',
                      operator: op1,
                      prefix: true,
                      argument: { type: 'Identifier', name: 'foo' }
                    },
                    right: {
                      type: 'UnaryExpression',
                      operator: op1,
                      prefix: true,
                      argument: { type: 'Identifier', name: 'bar' }
                    }
                  }
                }
              ]
            }
          );
        });
      });
    });


    it('should give binary operators their right precedence', function() {
      var operatorsByPrecedence = [['*', '/', '%'], ['+', '-'], ['<', '>', '<=', '>='], ['==','!=','===','!==']];
      for (var i = 0; i < operatorsByPrecedence.length - 1; ++i) {
        forEach(operatorsByPrecedence[i], function(op1) {
          forEach(operatorsByPrecedence[i + 1], function(op2) {
            expect(createAst('foo' + op1 + 'bar' + op2 + 'baz' + op1 + 'man')).toEqual(
              {
                type: 'Program',
                body: [
                  {
                    type: 'ExpressionStatement',
                    expression: {
                      type: 'BinaryExpression',
                      operator: op2,
                      left: {
                        type: 'BinaryExpression',
                        operator: op1,
                        left: { type: 'Identifier', name: 'foo' },
                        right: { type: 'Identifier', name: 'bar' }
                      },
                      right: {
                        type: 'BinaryExpression',
                        operator: op1,
                        left: { type: 'Identifier', name: 'baz' },
                        right: { type: 'Identifier', name: 'man' }
                      }
                    }
                  }
                ]
              }
            );
          });
        });
      }
    });


    it('should understand logical operators', function() {
      forEach(['||', '&&'], function(operator) {
        expect(createAst('foo' + operator + 'bar')).toEqual(
          {
            type: 'Program',
            body: [
              {
                type: 'ExpressionStatement',
                expression: {
                  type: 'LogicalExpression',
                  operator: operator,
                  left: { type: 'Identifier', name: 'foo' },
                  right: { type: 'Identifier', name: 'bar' }
                }
              }
            ]
          }
        );
      });
    });


    it('should associate logical operators left-to-right', function() {
      forEach(['||', '&&'], function(op) {
        expect(createAst('foo' + op + 'bar' + op + 'baz')).toEqual(
          {
            type: 'Program',
            body: [
              {
                type: 'ExpressionStatement',
                expression: {
                  type: 'LogicalExpression',
                  operator: op,
                  left: {
                    type: 'LogicalExpression',
                    operator: op,
                    left: { type: 'Identifier', name: 'foo' },
                    right: { type: 'Identifier', name: 'bar' }
                  },
                  right: { type: 'Identifier', name: 'baz' }
                }
              }
            ]
          }
        );
      });
    });


    it('should understand ternary operators', function() {
      expect(createAst('foo?bar:baz')).toEqual(
        {
          type: 'Program',
          body: [
            {
              type: 'ExpressionStatement',
              expression: {
                type: 'ConditionalExpression',
                test: { type: 'Identifier', name: 'foo' },
                alternate: { type: 'Identifier', name: 'bar' },
                consequent: { type: 'Identifier', name: 'baz' }
              }
            }
          ]
        }
      );
    });


    it('should associate the conditional operator right-to-left', function() {
      expect(createAst('foo0?foo1:foo2?bar0?bar1:bar2:man0?man1:man2')).toEqual(
        {
          type: 'Program',
          body: [
            {
              type: 'ExpressionStatement',
              expression: {
                type: 'ConditionalExpression',
                test: { type: 'Identifier', name: 'foo0' },
                alternate: { type: 'Identifier', name: 'foo1' },
                consequent: {
                  type: 'ConditionalExpression',
                  test: { type: 'Identifier', name: 'foo2' },
                  alternate: {
                    type: 'ConditionalExpression',
                    test: { type: 'Identifier', name: 'bar0' },
                    alternate: { type: 'Identifier', name: 'bar1' },
                    consequent: { type: 'Identifier', name: 'bar2' }
                  },
                  consequent: {
                    type: 'ConditionalExpression',
                    test: { type: 'Identifier', name: 'man0' },
                    alternate: { type: 'Identifier', name: 'man1' },
                    consequent: { type: 'Identifier', name: 'man2' }
                  }
                }
              }
            }
          ]
        }
      );
    });


    it('should understand assignment operator', function() {
      // Currently, only `=` is supported
      expect(createAst('foo=bar')).toEqual(
        {
          type: 'Program',
          body: [
            {
              type: 'ExpressionStatement',
              expression: {
                type: 'AssignmentExpression',
                left: { type: 'Identifier', name: 'foo' },
                right: { type: 'Identifier', name: 'bar' },
                operator: '='
              }
            }
          ]
        }
      );
    });


    it('should associate assignments right-to-left', function() {