text: describe('variable replacement', function() {
      var testrun;
  
      before(function(done) {
          this.run({
              collection: {
                  item: [{
                      event: [{
                          listen: 'test',
                          script: {
                              exec: [
                                  'var data = JSON.parse(responseBody);',
                                  'tests[\'Variable substitution\'] = (data.args.var===\'replaced\');',
                                  'tests[\'No blank variable substitution\'] = (data.args.novar===\'{{novar}}\');'
                              ]
                          }
                      }, {
                          listen: 'prerequest',
                          script: {exec: 'postman.setEnvironmentVariable(\'var\', \'replaced\');'}
                      }],
                      request: {
                          url: 'https://postman-echo.com/get?novar={{novar}}&var={{var}}',
                          method: 'GET',
                          body: {mode: 'formdata', formdata: []}
                      }
                  }]
              }
          }, function(err, results) {
              testrun = results;
              done(err);
          });
      });
  
      it('must have sent the request successfully', function() {
          expect(testrun).be.ok();
          expect(testrun.test.calledOnce).be.ok();
          expect(testrun.prerequest.calledOnce).be.ok();
          expect(testrun.request.calledOnce).be.ok();
  
          expect(testrun.request.getCall(0).args[0]).to.be(null);
      });
  
      it('must have substituted the available variable correctly', function () {
          var response = testrun.request.getCall(0).args[2],
              args = response.json().args;
  
          expect(args).to.be.ok();
          expect(args.var).to.eql('replaced');
      });
  
      it('must have not substituted the variable whose value is not set', function () {
          var response = testrun.request.getCall(0).args[2],
              args = response.json().args;
  
          expect(args).to.be.ok();
          expect(args.novar).to.eql('{{novar}}');
      });
  
      it('must have completed the run', function() {
          expect(testrun).be.ok();
          expect(testrun.done.calledOnce).be.ok();
          expect(testrun.done.getCall(0).args[0]).to.be(null);
          expect(testrun.start.calledOnce).be.ok();
      });
  });
  