title: TypeError: expect(...).to.be is not a function
body: <p>I am configuring my Karma amd mocha framework with grunt in my project. When I am running karma start I am getting below-mentioned error.</p>
  
  <p>I am getting this error in my console while running command : <code>Karma start</code></p>
  
  <pre><code>TypeError: expect(...).to.be is not a function
  </code></pre>
  
  <p>My Karma.confjs</p>
  
  <pre><code>// Karma configuration
  // Generated on Fri Nov 27 2015 11:48:47 GMT+0530 (India Standard Time)
  
  module.exports = function(config) {
    config.set({
  
      // base path that will be used to resolve all patterns (eg. files, exclude)
      basePath: '',
  
  
      // frameworks to use
      // available frameworks: https://npmjs.org/browse/keyword/karma-adapter
      frameworks: ['mocha', 'chai'],
  
  
      // list of files / patterns to load in the browser
      files: [
        'bower_components/angular/angular.js',
        'bower_components/angular-mocks/angular-mocks.js',
        'app/*.js',
        // 'test/specs/*.js',
        'test/specs/array.js',
        // 'test/specs/myCtlr-spec.js',
        //'test/*.js'
      ],
  
  
      // list of files to exclude
      exclude: [
      ],
  
  
      // preprocess matching files before serving them to the browser
      // available preprocessors: https://npmjs.org/browse/keyword/karma-preprocessor
      preprocessors: {
      },
  
  
      // test results reporter to use
      // possible values: 'dots', 'progress'
      // available reporters: https://npmjs.org/browse/keyword/karma-reporter
      reporters: ['progress','coverage'],
  
      preprocessors: {
          'src/app/**/*.js': ['coverage']
      },
      coverageReporter: {
          type: 'lcov',
          dir: 'coverage/'
      },
  
      // web server port
      port: 9876,
  
  
      // enable / disable colors in the output (reporters and logs)
      colors: true,
  
  
      // level of logging
      // possible values: config.LOG_DISABLE || config.LOG_ERROR || config.LOG_WARN || config.LOG_INFO || config.LOG_DEBUG
      logLevel: config.LOG_INFO,
  
  
      // enable / disable watching file and executing tests whenever any file changes
      autoWatch: true,
  
  
      // start these browsers
      // available browser launchers: https://npmjs.org/browse/keyword/karma-launcher
      // browsers: ['PhantomJS', 'Chrome'],
      browsers: ['Chrome'],
  
  
      // Continuous Integration mode
      // if true, Karma captures browsers, runs the tests and exits
      singleRun: false,
  
      // Concurrency level
      // how many browser should be started simultanous
      concurrency: Infinity
    })
  }
  </code></pre>
  
  <p>My array.js test</p>
  
  <pre><code>// var expect = require('chai').expect;
  
  describe("Mocha: The 'toBe' matcher compares with ===", function() {
    it("and has a positive case", function() {
      expect(true).to.be(true);
    });
  
    it("and can have a negative case", function() {
      expect(false).not.to.be(true);
    });
  });
  </code></pre>
  
  <p><a href="https://i.stack.imgur.com/LfISG.jpg"><img src="https://i.stack.imgur.com/LfISG.jpg" alt="enter image description here"></a></p>
  
  <p>Please suggest what I am missing.</p>