parseSpec.js

'use strict';

describe('parser', function() {
  describe('lexer', function() {
    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.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);

      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);

      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].string).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].string).toEqual('d"e');
    });

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

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

      expect(tokens[1].index).toEqual(1);
      expect(tokens[1].string).toEqual("'");

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

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

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

    it('should tokenize unicode', function() {
      var tokens = lex('"\\u00A0"');
      expect(tokens.length).toEqual(1);
      expect(tokens[0].string).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(map(tokens, function(t) { return t.text;})).toEqual(['a', '(', ')']);
    });

    it('should tokenize method invocation', function() {
      var tokens = lex("a.b.c (d) - e.f()");
      expect(map(tokens, 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].text).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($rootScope) {
      var tokens = lex("0.5E-10");
      expect(tokens[0].text).toEqual(0.5E-10);
      expect($rootScope.$eval("0.5E-10")).toEqual(0.5E-10);

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

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

      expect(function() {
        lex("0.5E-A");
      }).toThrow(new Error('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].text).toEqual(0.5);
    });

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

  var $filterProvider, scope;

  beforeEach(module(['$filterProvider', function (filterProvider) {
    $filterProvider = filterProvider;
  }]));


  forEach([true, false], function(cspEnabled) {

    describe('csp ' + cspEnabled, function() {

      beforeEach(inject(function ($rootScope, $sniffer) {
        scope = $rootScope;
        $sniffer.csp = cspEnabled;
        getterFnCache = {}; // clear cache
      }));


      it('should parse expressions', function() {
        expect(scope.$eval("-1")).toEqual(-1);
        expect(scope.$eval("1 + 2.5")).toEqual(3.5);
        expect(scope.$eval("1 + -2.5")).toEqual(-1.5);
        expect(scope.$eval("1+2*3/4")).toEqual(1+2*3/4);
        expect(scope.$eval("0--1+1.5")).toEqual(0- -1 + 1.5);
        expect(scope.$eval("-0--1++2*-3/-4")).toEqual(-0- -1+ +2*-3/-4);
        expect(scope.$eval("1/2*3")).toEqual(1/2*3);
      });

      it('should parse comparison', function() {
        expect(scope.$eval("false")).toBeFalsy();
        expect(scope.$eval("!true")).toBeFalsy();
        expect(scope.$eval("1==1")).toBeTruthy();
        expect(scope.$eval("1==true")).toBeTruthy();
        expect(scope.$eval("1===1")).toBeTruthy();
        expect(scope.$eval("1==='1'")).toBeFalsy();
        expect(scope.$eval("1===true")).toBeFalsy();
        expect(scope.$eval("'true'===true")).toBeFalsy();
        expect(scope.$eval("1!==2")).toBeTruthy();
        expect(scope.$eval("1!=='1'")).toBeTruthy();
        expect(scope.$eval("1!=2")).toBeTruthy();
        expect(scope.$eval("1<2")).toBeTruthy();
        expect(scope.$eval("1<=1")).toBeTruthy();
        expect(scope.$eval("1>2")).toEqual(1>2);
        expect(scope.$eval("2>=1")).toEqual(2>=1);
        expect(scope.$eval("true==2<3")).toEqual(true == 2<3);
        expect(scope.$eval("true===2<3")).toEqual(true === 2<3);
      });

      it('should parse logical', function() {
        expect(scope.$eval("0&&2")).toEqual(0&&2);
        expect(scope.$eval("0||2")).toEqual(0||2);
        expect(scope.$eval("0||1&&2")).toEqual(0||1&&2);
      });
      
      it('should parse ternary', function(){
        var returnTrue = scope.returnTrue = function(){ return true; };
        var returnFalse = scope.returnFalse = function(){ return false; };
        var returnString = scope.returnString = function(){ return 'asd'; };
        var returnInt = scope.returnInt = function(){ return 123; };
        var identity = scope.identity = function(x){ return x; };

        // Simple.
        expect(scope.$eval('0?0:2')).toEqual(0?0:2);
        expect(scope.$eval('1?0:2')).toEqual(1?0:2);
        
        // Nested on the left.
        expect(scope.$eval('0?0?0:0:2')).toEqual(0?0?0:0:2);
        expect(scope.$eval('1?0?0:0:2')).toEqual(1?0?0:0:2);
        expect(scope.$eval('0?1?0:0:2')).toEqual(0?1?0:0:2);
        expect(scope.$eval('0?0?1:0:2')).toEqual(0?0?1:0:2);
        expect(scope.$eval('0?0?0:2:3')).toEqual(0?0?0:2:3);
        expect(scope.$eval('1?1?0:0:2')).toEqual(1?1?0:0:2);
        expect(scope.$eval('1?1?1:0:2')).toEqual(1?1?1:0:2);
        expect(scope.$eval('1?1?1:2:3')).toEqual(1?1?1:2:3);
        expect(scope.$eval('1?1?1:2:3')).toEqual(1?1?1:2:3);
        
        // Nested on the right.
        expect(scope.$eval('0?0:0?0:2')).toEqual(0?0:0?0:2);
        expect(scope.$eval('1?0:0?0:2')).toEqual(1?0:0?0:2);
        expect(scope.$eval('0?1:0?0:2')).toEqual(0?1:0?0:2);
        expect(scope.$eval('0?0:1?0:2')).toEqual(0?0:1?0:2);
        expect(scope.$eval('0?0:0?2:3')).toEqual(0?0:0?2:3);
        expect(scope.$eval('1?1:0?0:2')).toEqual(1?1:0?0:2);
        expect(scope.$eval('1?1:1?0:2')).toEqual(1?1:1?0:2);
        expect(scope.$eval('1?1:1?2:3')).toEqual(1?1:1?2:3);
        expect(scope.$eval('1?1:1?2:3')).toEqual(1?1:1?2:3);
        
        // Precedence with respect to logical operators.
        expect(scope.$eval('0&&1?0:1')).toEqual(0&&1?0:1);
        expect(scope.$eval('1||0?0:0')).toEqual(1||0?0:0);
        
        expect(scope.$eval('0?0&&1:2')).toEqual(0?0&&1:2);
        expect(scope.$eval('0?1&&1:2')).toEqual(0?1&&1:2);
        expect(scope.$eval('0?0||0:1')).toEqual(0?0||0:1);
        expect(scope.$eval('0?0||1:2')).toEqual(0?0||1:2);
        
        expect(scope.$eval('1?0&&1:2')).toEqual(1?0&&1:2);
        expect(scope.$eval('1?1&&1:2')).toEqual(1?1&&1:2);
        expect(scope.$eval('1?0||0:1')).toEqual(1?0||0:1);
        expect(scope.$eval('1?0||1:2')).toEqual(1?0||1:2);
        
        expect(scope.$eval('0?1:0&&1')).toEqual(0?1:0&&1);
        expect(scope.$eval('0?2:1&&1')).toEqual(0?2:1&&1);
        expect(scope.$eval('0?1:0||0')).toEqual(0?1:0||0);
        expect(scope.$eval('0?2:0||1')).toEqual(0?2:0||1);
        
        expect(scope.$eval('1?1:0&&1')).toEqual(1?1:0&&1);
        expect(scope.$eval('1?2:1&&1')).toEqual(1?2:1&&1);
        expect(scope.$eval('1?1:0||0')).toEqual(1?1:0||0);
        expect(scope.$eval('1?2:0||1')).toEqual(1?2:0||1);
        
        // Function calls.
        expect(scope.$eval('returnTrue() ? returnString() : returnInt()')).toEqual(returnTrue() ? returnString() : returnInt());
        expect(scope.$eval('returnFalse() ? returnString() : returnInt()')).toEqual(returnFalse() ? returnString() : returnInt());
        expect(scope.$eval('returnTrue() ? returnString() : returnInt()')).toEqual(returnTrue() ? returnString() : returnInt());
        expect(scope.$eval('identity(returnFalse() ? returnString() : returnInt())')).toEqual(identity(returnFalse() ? returnString() : returnInt()));
      });

      it('should parse string', function() {
        expect(scope.$eval("'a' + 'b c'")).toEqual("ab c");
      });

      it('should parse filters', function() {
        $filterProvider.register('substring', valueFn(function(input, start, end) {
          return input.substring(start, end);
        }));

        expect(function() {
          scope.$eval("1|nonexistent");
        }).toThrow(new Error("Unknown provider: nonexistentFilterProvider <- nonexistentFilter"));

        scope.offset =  3;
        expect(scope.$eval("'abcd'|substring:1:offset")).toEqual("bc");
        expect(scope.$eval("'abcd'|substring:1:3|uppercase")).toEqual("BC");
      });

      it('should access scope', function() {
        scope.a =  123;
        scope.b = {c: 456};
        expect(scope.$eval("a", scope)).toEqual(123);
        expect(scope.$eval("b.c", scope)).toEqual(456);
        expect(scope.$eval("x.y.z", scope)).not.toBeDefined();
      });

      it('should resolve deeply nested paths (important for CSP mode)', function() {
        scope.a = {b: {c: {d: {e: {f: {g: {h: {i: {j: {k: {l: {m: {n: 'nooo!'}}}}}}}}}}}}};
        expect(scope.$eval("a.b.c.d.e.f.g.h.i.j.k.l.m.n", scope)).toBe('nooo!');
      });

      it('should be forgiving', function() {
        scope.a = {b: 23};
        expect(scope.$eval('b')).toBeUndefined();
        expect(scope.$eval('a.x')).toBeUndefined();
        expect(scope.$eval('a.b.c.d')).toBeUndefined();
      });

      it('should support property names that collide with native object properties', function() {
        // regression
        scope.watch = 1;
        scope.constructor = 2;
        scope.toString = 3;

        expect(scope.$eval('watch', scope)).toBe(1);
        expect(scope.$eval('constructor', scope)).toBe(2);
        expect(scope.$eval('toString', scope)).toBe(3);
      });

      it('should evaluate grouped expressions', function() {
        expect(scope.$eval("(1+2)*3")).toEqual((1+2)*3);
      });

      it('should evaluate assignments', function() {
        expect(scope.$eval("a=12")).toEqual(12);
        expect(scope.a).toEqual(12);

        expect(scope.$eval("x.y.z=123;")).toEqual(123);
        expect(scope.x.y.z).toEqual(123);

        expect(scope.$eval("a=123; b=234")).toEqual(234);
        expect(scope.a).toEqual(123);
        expect(scope.b).toEqual(234);
      });

      it('should evaluate function call without arguments', function() {
        scope['const'] =  function(a,b){return 123;};
        expect(scope.$eval("const()")).toEqual(123);
      });

      it('should evaluate function call with arguments', function() {
        scope.add =  function(a,b) {
          return a+b;
        };
        expect(scope.$eval("add(1,2)")).toEqual(3);
      });

      it('should evaluate function call from a return value', function() {
        scope.val = 33;
        scope.getter = function() { return function() { return this.val; }};
        expect(scope.$eval("getter()()")).toBe(33);
      });

      it('should evaluate multiplication and division', function() {
        scope.taxRate =  8;
        scope.subTotal =  100;
        expect(scope.$eval("taxRate / 100 * subTotal")).toEqual(8);
        expect(scope.$eval("subTotal * taxRate / 100")).toEqual(8);
      });

      it('should evaluate array', function() {
        expect(scope.$eval("[]").length).toEqual(0);
        expect(scope.$eval("[1, 2]").length).toEqual(2);
        expect(scope.$eval("[1, 2]")[0]).toEqual(1);
        expect(scope.$eval("[1, 2]")[1]).toEqual(2);
      });

      it('should evaluate array access', function() {
        expect(scope.$eval("[1][0]")).toEqual(1);
        expect(scope.$eval("[[1]][0][0]")).toEqual(1);
        expect(scope.$eval("[].length")).toEqual(0);
        expect(scope.$eval("[1, 2].length")).toEqual(2);
      });

      it('should evaluate object', function() {
        expect(toJson(scope.$eval("{}"))).toEqual("{}");
        expect(toJson(scope.$eval("{a:'b'}"))).toEqual('{"a":"b"}');
        expect(toJson(scope.$eval("{'a':'b'}"))).toEqual('{"a":"b"}');
        expect(toJson(scope.$eval("{\"a\":'b'}"))).toEqual('{"a":"b"}');
      });

      it('should evaluate object access', function() {
        expect(scope.$eval("{false:'WC', true:'CC'}[false]")).toEqual("WC");
      });

      it('should evaluate JSON', function() {
        expect(toJson(scope.$eval("[{}]"))).toEqual("[{}]");
        expect(toJson(scope.$eval("[{a:[]}, {b:1}]"))).toEqual('[{"a":[]},{"b":1}]');
      });

      it('should evaluate multiple statements', function() {
        expect(scope.$eval("a=1;b=3;a+b")).toEqual(4);
        expect(scope.$eval(";;1;;")).toEqual(1);
      });

      it('should evaluate object methods in correct context (this)', function() {
        var C = function () {
          this.a = 123;
        };
        C.prototype.getA = function() {
          return this.a;
        };

        scope.obj = new C();
        expect(scope.$eval("obj.getA()")).toEqual(123);
        expect(scope.$eval("obj['getA']()")).toEqual(123);
      });

      it('should evaluate methods in correct context (this) in argument', function() {
        var C = function () {
          this.a = 123;
        };
        C.prototype.sum = function(value) {
          return this.a + value;
        };
        C.prototype.getA = function() {
          return this.a;
        };

        scope.obj = new C();
        expect(scope.$eval("obj.sum(obj.getA())")).toEqual(246);
        expect(scope.$eval("obj['sum'](obj.getA())")).toEqual(246);
      });

      it('should evaluate objects on scope context', function() {
        scope.a =  "abc";
        expect(scope.$eval("{a:a}").a).toEqual("abc");
      });

      it('should evaluate field access on function call result', function() {
        scope.a =  function() {
          return {name:'misko'};
        };
        expect(scope.$eval("a().name")).toEqual("misko");
      });

      it('should evaluate field access after array access', function () {
        scope.items =  [{}, {name:'misko'}];
        expect(scope.$eval('items[1].name')).toEqual("misko");
      });

      it('should evaluate array assignment', function() {
        scope.items =  [];

        expect(scope.$eval('items[1] = "abc"')).toEqual("abc");
        expect(scope.$eval('items[1]')).toEqual("abc");
    //    Dont know how to make this work....
    //    expect(scope.$eval('books[1] = "moby"')).toEqual("moby");
    //    expect(scope.$eval('books[1]')).toEqual("moby");
      });

      it('should evaluate grouped filters', function() {
        scope.name = 'MISKO';
        expect(scope.$eval('n = (name|lowercase)')).toEqual('misko');
        expect(scope.$eval('n')).toEqual('misko');
      });

      it('should evaluate remainder', function() {
        expect(scope.$eval('1%2')).toEqual(1);
      });

      it('should evaluate sum with undefined', function() {
        expect(scope.$eval('1+undefined')).toEqual(1);
        expect(scope.$eval('undefined+1')).toEqual(1);
      });

      it('should throw exception on non-closed bracket', function() {
        expect(function() {
          scope.$eval('[].count(');
        }).toThrow('Unexpected end of expression: [].count(');
      });

      it('should evaluate double negation', function() {
        expect(scope.$eval('true')).toBeTruthy();
        expect(scope.$eval('!true')).toBeFalsy();
        expect(scope.$eval('!!true')).toBeTruthy();
        expect(scope.$eval('{true:"a", false:"b"}[!!true]')).toEqual('a');
      });

      it('should evaluate negation', function() {
        expect(scope.$eval("!false || true")).toEqual(!false || true);
        expect(scope.$eval("!11 == 10")).toEqual(!11 == 10);
        expect(scope.$eval("12/6/2")).toEqual(12/6/2);
      });

      it('should evaluate exclamation mark', function() {
        expect(scope.$eval('suffix = "!"')).toEqual('!');
      });

      it('should evaluate minus', function() {
        expect(scope.$eval("{a:'-'}")).toEqual({a: "-"});
      });

      it('should evaluate undefined', function() {
        expect(scope.$eval("undefined")).not.toBeDefined();
        expect(scope.$eval("a=undefined")).not.toBeDefined();
        expect(scope.a).not.toBeDefined();
      });

      it('should allow assignment after array dereference', function() {
        scope.obj = [{}];
        scope.$eval('obj[0].name=1');
        expect(scope.obj.name).toBeUndefined();
        expect(scope.obj[0].name).toEqual(1);
      });

      it('should short-circuit AND operator', function() {
        scope.run = function() {
          throw "IT SHOULD NOT HAVE RUN";
        };
        expect(scope.$eval('false && run()')).toBe(false);
      });

      it('should short-circuit OR operator', function() {
        scope.run = function() {
          throw "IT SHOULD NOT HAVE RUN";
        };
        expect(scope.$eval('true || run()')).toBe(true);
      });


      it('should support method calls on primitive types', function() {
        scope.empty = '';
        scope.zero = 0;
        scope.bool = false;

        expect(scope.$eval('empty.substr(0)')).toBe('');
        expect(scope.$eval('zero.toString()')).toBe('0');
        expect(scope.$eval('bool.toString()')).toBe('false');
      });


      describe('promises', function() {
        var deferred, promise, q;

        beforeEach(inject(function($q) {
          q = $q;
          deferred = q.defer();
          promise = deferred.promise;
        }));

        describe('{{promise}}', function() {
          it('should evaluated resolved promise and get its value', function() {
            deferred.resolve('hello!');
            scope.greeting = promise;
            expect(scope.$eval('greeting')).toBe(undefined);
            scope.$digest();
            expect(scope.$eval('greeting')).toBe('hello!');
          });


          it('should evaluated rejected promise and ignore the rejection reason', function() {
            deferred.reject('sorry');
            scope.greeting = promise;
            expect(scope.$eval('gretting')).toBe(undefined);
            scope.$digest();
            expect(scope.$eval('greeting')).toBe(undefined);
          });


          it('should evaluate a promise and eventualy get its value', function() {
            scope.greeting = promise;
            expect(scope.$eval('greeting')).toBe(undefined);

            scope.$digest();
            expect(scope.$eval('greeting')).toBe(undefined);

            deferred.resolve('hello!');
            expect(scope.$eval('greeting')).toBe(undefined);
            scope.$digest();
            expect(scope.$eval('greeting')).toBe('hello!');
          });


          it('should evaluate a promise and eventualy ignore its rejection', function() {
            scope.greeting = promise;
            expect(scope.$eval('greeting')).toBe(undefined);

            scope.$digest();
            expect(scope.$eval('greeting')).toBe(undefined);

            deferred.reject('sorry');
            expect(scope.$eval('greeting')).toBe(undefined);
            scope.$digest();
            expect(scope.$eval('greeting')).toBe(undefined);
          });
        });

        describe('dereferencing', function() {
          it('should evaluate and dereference properties leading to and from a promise', function() {
            scope.obj = {greeting: promise};
            expect(scope.$eval('obj.greeting')).toBe(undefined);
            expect(scope.$eval('obj.greeting.polite')).toBe(undefined);

            scope.$digest();
            expect(scope.$eval('obj.greeting')).toBe(undefined);
            expect(scope.$eval('obj.greeting.polite')).toBe(undefined);

            deferred.resolve({polite: 'Good morning!'});
            scope.$digest();
            expect(scope.$eval('obj.greeting')).toEqual({polite: 'Good morning!'});
            expect(scope.$eval('obj.greeting.polite')).toBe('Good morning!');
          });

          it('should evaluate and dereference properties leading to and from a promise via bracket ' +
              'notation', function() {
            scope.obj = {greeting: promise};
            expect(scope.$eval('obj["greeting"]')).toBe(undefined);
            expect(scope.$eval('obj["greeting"]["polite"]')).toBe(undefined);

            scope.$digest();
            expect(scope.$eval('obj["greeting"]')).toBe(undefined);
            expect(scope.$eval('obj["greeting"]["polite"]')).toBe(undefined);

            deferred.resolve({polite: 'Good morning!'});
            scope.$digest();
            expect(scope.$eval('obj["greeting"]')).toEqual({polite: 'Good morning!'});
            expect(scope.$eval('obj["greeting"]["polite"]')).toBe('Good morning!');
          });


          it('should evaluate and dereference array references leading to and from a promise',
              function() {
            scope.greetings = [promise];
            expect(scope.$eval('greetings[0]')).toBe(undefined);
            expect(scope.$eval('greetings[0][0]')).toBe(undefined);

            scope.$digest();
            expect(scope.$eval('greetings[0]')).toBe(undefined);
            expect(scope.$eval('greetings[0][0]')).toBe(undefined);

            deferred.resolve(['Hi!', 'Cau!']);
            scope.$digest();
            expect(scope.$eval('greetings[0]')).toEqual(['Hi!', 'Cau!']);
            expect(scope.$eval('greetings[0][0]')).toBe('Hi!');
          });


          it('should evaluate and dereference promises used as function arguments', function() {
            scope.greet = function(name) { return 'Hi ' + name + '!'; };
            scope.name = promise;
            expect(scope.$eval('greet(name)')).toBe('Hi undefined!');

            scope.$digest();
            expect(scope.$eval('greet(name)')).toBe('Hi undefined!');

            deferred.resolve('Veronica');
            expect(scope.$eval('greet(name)')).toBe('Hi undefined!');

            scope.$digest();
            expect(scope.$eval('greet(name)')).toBe('Hi Veronica!');
          });


          it('should evaluate and dereference promises used as array indexes', function() {
            scope.childIndex = promise;
            scope.kids = ['Adam', 'Veronica', 'Elisa'];
            expect(scope.$eval('kids[childIndex]')).toBe(undefined);

            scope.$digest();
            expect(scope.$eval('kids[childIndex]')).toBe(undefined);

            deferred.resolve(1);
            expect(scope.$eval('kids[childIndex]')).toBe(undefined);

            scope.$digest();
            expect(scope.$eval('kids[childIndex]')).toBe('Veronica');
          });


          it('should evaluate and dereference promises used as keys in bracket notation', function() {
            scope.childKey = promise;
            scope.kids = {'a': 'Adam', 'v': 'Veronica', 'e': 'Elisa'};

            expect(scope.$eval('kids[childKey]')).toBe(undefined);

            scope.$digest();
            expect(scope.$eval('kids[childKey]')).toBe(undefined);

            deferred.resolve('v');
            expect(scope.$eval('kids[childKey]')).toBe(undefined);

            scope.$digest();
            expect(scope.$eval('kids[childKey]')).toBe('Veronica');
          });


          it('should not mess with the promise if it was not directly evaluated', function() {
            scope.obj = {greeting: promise, username: 'hi'};
            var obj = scope.$eval('obj');
            expect(obj.username).toEqual('hi');
            expect(typeof obj.greeting.then).toBe('function');
          });
        });
      });


      describe('assignable', function() {
        it('should expose assignment function', inject(function($parse) {
          var fn = $parse('a');
          expect(fn.assign).toBeTruthy();
          var scope = {};
          fn.assign(scope, 123);
          expect(scope).toEqual({a:123});
        }));
      });


      describe('locals', function() {
        it('should expose local variables', inject(function($parse) {
          expect($parse('a')({a: 0}, {a: 1})).toEqual(1);
          expect($parse('add(a,b)')({b: 1, add: function(a, b) { return a + b; }}, {a: 2})).toEqual(3);
        }));

        it('should expose traverse locals', inject(function($parse) {
          expect($parse('a.b')({a: {b: 0}}, {a: {b:1}})).toEqual(1);
          expect($parse('a.b')({a: null}, {a: {b:1}})).toEqual(1);
          expect($parse('a.b')({a: {b: 0}}, {a: null})).toEqual(undefined);
        }));
      });

      describe('literal', function() {
        it('should mark scalar value expressions as literal', inject(function($parse) {
          expect($parse('0').literal).toBe(true);
          expect($parse('"hello"').literal).toBe(true);
          expect($parse('true').literal).toBe(true);
          expect($parse('false').literal).toBe(true);
          expect($parse('null').literal).toBe(true);
          expect($parse('undefined').literal).toBe(true);
        }));

        it('should mark array expressions as literal', inject(function($parse) {
          expect($parse('[]').literal).toBe(true);
          expect($parse('[1, 2, 3]').literal).toBe(true);
          expect($parse('[1, identifier]').literal).toBe(true);
        }));

        it('should mark object expressions as literal', inject(function($parse) {
          expect($parse('{}').literal).toBe(true);
          expect($parse('{x: 1}').literal).toBe(true);
          expect($parse('{foo: bar}').literal).toBe(true);
        }));

        it('should not mark function calls or operator expressions as literal', inject(function($parse) {
          expect($parse('1 + 1').literal).toBe(false);
          expect($parse('call()').literal).toBe(false);
          expect($parse('[].length').literal).toBe(false);
        }));
      });

      describe('constant', function() {
        it('should mark scalar value expressions as constant', inject(function($parse) {
          expect($parse('12.3').constant).toBe(true);
          expect($parse('"string"').constant).toBe(true);
          expect($parse('true').constant).toBe(true);
          expect($parse('false').constant).toBe(true);
          expect($parse('null').constant).toBe(true);
          expect($parse('undefined').constant).toBe(true);
        }));

        it('should mark arrays as constant if they only contain constant elements', inject(function($parse) {
          expect($parse('[]').constant).toBe(true);
          expect($parse('[1, 2, 3]').constant).toBe(true);
          expect($parse('["string", null]').constant).toBe(true);
          expect($parse('[[]]').constant).toBe(true);
          expect($parse('[1, [2, 3], {4: 5}]').constant).toBe(true);
        }));

        it('should not mark arrays as constant if they contain any non-constant elements', inject(function($parse) {
          expect($parse('[foo]').constant).toBe(false);
          expect($parse('[x + 1]').constant).toBe(false);
          expect($parse('[bar[0]]').constant).toBe(false);
        }));

        it('should mark complex expressions involving constant values as constant', inject(function($parse) {
          expect($parse('!true').constant).toBe(true);
          expect($parse('1 - 1').constant).toBe(true);
          expect($parse('"foo" + "bar"').constant).toBe(true);
          expect($parse('5 != null').constant).toBe(true);
          expect($parse('{standard: 4/3, wide: 16/9}').constant).toBe(true);
        }));

        it('should not mark any expression involving variables or function calls as constant', inject(function($parse) {
          expect($parse('true.toString()').constant).toBe(false);
          expect($parse('foo(1, 2, 3)').constant).toBe(false);
          expect($parse('"name" + id').constant).toBe(false);
        }));
      });
    });
  });
});