text: var Twig = Twig || requireUncached("../twig"),
      twig = twig || Twig.twig;
  
  describe("Twig.js Tests ->", function() {
      describe("empty test ->", function() {
          it("should identify numbers as not empty", function() {
              // number
              twig({data: '{{ 1 is empty }}'}).render().should.equal("false" );
              twig({data: '{{ 0 is empty }}'}).render().should.equal("false" );
          });
          
          it("should identify empty strings", function() {
              // String
              twig({data: '{{ "" is empty }}'}).render().should.equal("true" );
              twig({data: '{{ "test" is empty }}'}).render().should.equal("false" );
          });
          
          it("should identify empty arrays", function() {
              // Array
              twig({data: '{{ [] is empty }}'}).render().should.equal("true" );
              twig({data: '{{ ["1"] is empty }}'}).render().should.equal("false" );
          });
          
          it("should identify empty objects", function() {
              // Object
              twig({data: '{{ {} is empty }}'}).render().should.equal("true" );
              twig({data: '{{ {"a":"b"} is empty }}'}).render().should.equal("false" );
              twig({data: '{{ {"a":"b"} is not empty }}'}).render().should.equal("true" );
          });
      });
          
      describe("odd test ->", function() {
          it("should identify a number as odd", function() {
              twig({data: '{{ (1 + 4) is odd }}'}).render().should.equal("true" );
              twig({data: '{{ 6 is odd }}'}).render().should.equal("false" );
          });
      });
      
      describe("even test ->", function() {
          it("should identify a number as even", function() {
              twig({data: '{{ (1 + 4) is even }}'}).render().should.equal("false" );
              twig({data: '{{ 6 is even }}'}).render().should.equal("true" );
          });
      });
  
      describe("divisibleby test ->", function() {
          it("should determine if a number is divisible by the given number", function() {
              twig({data: '{{ 5 is divisibleby(3) }}'}).render().should.equal("false" );
              twig({data: '{{ 6 is divisibleby(3) }}'}).render().should.equal("true" );
          });
      });
  
      describe("defined test ->", function() {
          it("should identify a key as defined if it exists in the render context", function() {
              twig({data: '{{ key is defined }}'}).render().should.equal("false" );
              twig({data: '{{ key is defined }}'}).render({key: "test"}).should.equal( "true" );
              var context = {
                  key: {
                      foo: "bar",
                      nothing: null
                  },
                  nothing: null
              };
              twig({data: '{{ key.foo is defined }}'}).render(context).should.equal( "true" );
              twig({data: '{{ key.bar is defined }}'}).render(context).should.equal( "false" );
              twig({data: '{{ key.foo.bar is defined }}'}).render(context).should.equal( "false" );
              twig({data: '{{ foo.bar is defined }}'}).render(context).should.equal( "false" );
              twig({data: '{{ nothing is defined }}'}).render(context).should.equal( "true" );
              twig({data: '{{ key.nothing is defined }}'}).render(context).should.equal( "true" );
          });
      });
  
      describe("none test ->", function() {
          it("should identify a key as none if it exists in the render context and is null", function() {
              twig({data: '{{ key is none }}'}).render().should.equal("false");
              twig({data: '{{ key is none }}'}).render({key: "test"}).should.equal("false");
              twig({data: '{{ key is none }}'}).render({key: null}).should.equal("true");
              twig({data: '{{ key is null }}'}).render({key: null}).should.equal("true");
          });
      });
  
      describe("`sameas` backwards compatibility with `same as`", function () {
          it("should identify the exact same type as true", function() {
              twig({data: '{{ true is sameas(true) }}'}).render().should.equal("true");
              twig({data: '{{ a is sameas(1) }}'}).render({a: 1}).should.equal("true");
              twig({data: '{{ a is sameas("test") }}'}).render({a: "test"}).should.equal("true");
              twig({data: '{{ a is sameas(true) }}'}).render({a: true}).should.equal("true");
          });
          it("should identify the different types as false", function() {
              twig({data: '{{ false is sameas(true) }}'}).render().should.equal("false");
              twig({data: '{{ true is sameas(1) }}'}).render().should.equal("false");
              twig({data: '{{ false is sameas("") }}'}).render().should.equal("false");
              twig({data: '{{ a is sameas(1) }}'}).render({a: "1"}).should.equal("false");
          });
      });
  
      describe("same as test ->", function() {
          it("should identify the exact same type as true", function() {
              twig({data: '{{ true is same as(true) }}'}).render().should.equal("true");
              twig({data: '{{ a is same as(1) }}'}).render({a: 1}).should.equal("true");
              twig({data: '{{ a is same as("test") }}'}).render({a: "test"}).should.equal("true");
              twig({data: '{{ a is same as(true) }}'}).render({a: true}).should.equal("true");
          });
          it("should identify the different types as false", function() {
              twig({data: '{{ false is same as(true) }}'}).render().should.equal("false");
              twig({data: '{{ true is same as(1) }}'}).render().should.equal("false");
              twig({data: '{{ false is same as("") }}'}).render().should.equal("false");
              twig({data: '{{ a is same as(1) }}'}).render({a: "1"}).should.equal("false");
          });
      });
  
      describe("iterable test ->", function() {
          var data = {
                  foo: [],
                  traversable: 15,
                  obj: {},
                  val: "test"
          };
  
          it("should fail on non-iterable data types", function() {
              twig({data: "{{ val is iterable ? 'ok' : 'ko' }}"}).render(data).should.equal("ko");
              twig({data: "{{ val is iterable ? 'ok' : 'ko' }}"}).render({val: null}).should.equal("ko");
              twig({data: "{{ val is iterable ? 'ok' : 'ko' }}"}).render({}).should.equal("ko");
          });
  
          it("should pass on iterable data types", function() {
              twig({data: "{{ foo is iterable ? 'ok' : 'ko' }}"}).render(data).should.equal("ok");
              twig({data: "{{ obj is iterable ? 'ok' : 'ko' }}"}).render(data).should.equal("ok");
          });
      });
  });
  