How do I load a binary file during javascript unit test?

Question

In my application, the user uses HTML5 drag and drop to process a binary file. That part of the code works fine. In chrome, I drag a binary file and use a FileReader to create an arrayBuffer. That all seems to work fine. I am writing tests for this functionality and I am at a loss. How do I load a binary file into my unit test? For the bit of code I am testing, I only need an arrayBuffer. Currently, I am creating the arrayBuffer manually, but that isn't a sustainable solution. In order for my tests to be effective, I need to be able to throw a new binary file in at anytime and make a new test. My testing environment is testacular+jasmine.

( function() {"use strict";
    function loadSimpleDataView() {
      //instead of defining ArrayBuffer, 
      //I want it to be generated based upon an external file
      var buffer = new ArrayBuffer(4), dataView = new DataView(buffer), int8View = new Int8Array(buffer);
      int8View.set([0x00,0x01,0x02,0x03]);

      return dataView;
    }

    describe('mymodule', function() {

      it('mytest', function() {
        var dataView  = loadSimpleDataView();

        expect(dataView).toBeDefined();
        //do rest of tests
      });
    });
  }());

Answer 1

I use grunt to build my project and run my unit tests. Below is my grunt.js, testacular.conf.js, and test (javaclassstreamreader.spec.js). In short, grunt starts up grunt-server which is configured to serve the binary data files. Testacular is configured to proxy the grunt-server. In the test, XMLHttpRequest is used to retrieve the binary file. Everything works, but it seems a bit complex. Is there an easier way?

grunt.js:

/*global module:false*/
module.exports = function(grunt) {"use strict";

  // Project configuration.
  grunt.initConfig({
    pkg : '<json:package.json>',
    meta : {
      banner : '/*! <%= pkg.title || pkg.name %> - v<%= pkg.version %> - ' + '<%= grunt.template.today("yyyy-mm-dd") %>\n' + '<%= pkg.homepage ? "* " + pkg.homepage + "\n" : "" %>' + '* Copyright (c) <%= grunt.template.today("yyyy") %> <%= pkg.author.name %>;' + ' Licensed <%= _.pluck(pkg.licenses, "type").join(", ") %> */'
    },
    lint : {
      files : ['grunt.js', 'src/*.js', 'src/public/js/**/*.js', 'src/specs/**/*.js']
    },
    watch : {
      files : '<config:lint.files>',
      tasks : 'default'
    },
    exec : {
      ensure_generated_directory : {
        command : 'mkdir -p generated/js/'
      }
    },
    clean : {
      all : ['generated']
    },
    jshint : {
      files : '<config:lint.files>',
      options : {
        curly : true,
        eqeqeq : true,
        forin : true,
        immed : true,
        latedef : true,
        newcap : true,
        noarg : true,
        sub : true,
        undef : true,
        unused : true,
        strict : true,
        boss : true,
        eqnull : true,
        es5 : true,
        browser : true,
        jquery : true,
        devel : true
      },
      globals : {
        //jasmine
        describe : false,
        it : false,
        expect : false,
        //commonjs
        require : false,
        exports : true,
        //angular
        angular : false
      }
    },
    'closure-compiler' : {
      frontend : {
        closurePath : 'closure-compiler',
        js : ['src/*.js', 'src/public/js/**/*.js'],
        jsOutputFile : 'generated/js/complete-app.js',
        options : {
          externs : 'externs.js',
          compilation_level : 'SIMPLE_OPTIMIZATIONS',
          language_in : 'ECMASCRIPT5_STRICT',
          logging_level : 'ALL',
          debug : null,
          warning_level : 'verbose',
          summary_detail_level : 3,
          formatting : ['PRETTY_PRINT', 'PRINT_INPUT_DELIMITER'],
          common_js_entry_module : 'src/public/js/app.js',
          process_common_js_modules : null,
          process_jquery_primitives : null,
          common_js_module_path_prefix : 'src'
        }
      }
    },
    testacularServer : {
      integration : {
        options : {
          keepalive : true
        },
        configFile : 'testacular.conf.js',
        autoWatch : false,
        singleRun : true
      }
    },
    server : {
      port : 18081,
      base : './src/specs/data'
    }
  });

  // Default task.
  grunt.registerTask('default', 'lint exec:ensure_generated_directory closure-compiler server testacularServer:integration');
  grunt.loadNpmTasks('grunt-contrib-watch');
  grunt.loadNpmTasks('grunt-closure-compiler');
  grunt.loadNpmTasks('grunt-exec');
  grunt.loadNpmTasks('grunt-contrib-clean');
  grunt.loadNpmTasks('grunt-testacular');
};

testacular.conf.js:

// Testacular configuration
// Generated on Tue Jan 01 2013 03:17:01 GMT-0500 (EST)
/*global basePath:true */
/*global files:true */
/*global JASMINE:false */
/*global JASMINE_ADAPTER:false */
/*global exclude:true */
/*global reporters:true */
/*global port:true */
/*global runnerPort:true */
/*global colors:true */
/*global logLevel:true */
/*global LOG_INFO:false */
/*global autoWatch:true */
/*global browsers:true */
/*global captureTimeout:true */
/*global singleRun:true */

// base path, that will be used to resolve files and exclude
basePath = '.';


// list of files / patterns to load in the browser
files = [
  JASMINE,
  JASMINE_ADAPTER,
  'src/public/lib/jquery/1.7.2/jquery-1.7.2.min.js',
  'src/public/lib/jquery-ui/1.8.20.custom/jquery-ui-1.8.20.custom.min.js',
  'src/public/lib/angular/1.0.1/angular-1.0.1.min.js',
  'src/public/lib/filer.min.js',
  'generated/js/complete-app.js',
  'src/specs/**/*.spec.js'
];


// list of files to exclude
exclude = [
];


// test results reporter to use
// possible values: 'dots', 'progress', 'junit'
reporters = ['progress'];


// web server port
port = 18080;


// cli runner port
runnerPort = 9100;

//proxy
proxies = {
    '/test-data/': 'http://localhost:18081/'
};

// enable / disable colors in the output (reporters and logs)
colors = true;


// level of logging
// possible values: LOG_DISABLE || LOG_ERROR || LOG_WARN || LOG_INFO || LOG_DEBUG
logLevel = LOG_INFO;


// enable / disable watching file and executing tests whenever any file changes
autoWatch = true;


// Start these browsers, currently available:
// - Chrome
// - ChromeCanary
// - Firefox
// - Opera
// - Safari (only Mac)
// - PhantomJS
// - IE (only Windows)
browsers = ['Chrome'];


// If browser does not capture in given timeout [ms], kill it
captureTimeout = 5000;


// Continuous Integration mode
// if true, it capture browsers, run tests and exit
singleRun = false;

javaclassstreamreader.spec.js:

/*global module$javaclassstreamreader:false */
/*global waitsFor:false */
/*global runs:false */
/*global dump:false */


( function() {"use strict";

    var JavaClassStreamReader = module$javaclassstreamreader.JavaClassStreamReader;

    function loadSimpleDataView(callback) {
      var dataView;
      var xhr = new XMLHttpRequest();
      xhr.open('GET', '/test-data/MyInterface.class', true); 
      xhr.responseType = 'arraybuffer';
      xhr.onload = function() {
          dataView = new DataView(this.response);
          callback(dataView);
      };
      xhr.onerror = dump;
      xhr.send();
    }

    describe('javaclassstreamreader', function() {

      it('reader can be constructed', function() {
        var hasData = false,reader;

        loadSimpleDataView(function(dataView) {
          reader = new JavaClassStreamReader(dataView);
          hasData = true;
        });

        waitsFor(function() {
          return hasData;
        }, "Never retrieved file", 3000);
        runs(function() {

          expect(reader.offset).toBe(0);

          var firstBytes = reader.getU4();
          dump(firstBytes.toString(16));
          expect(firstBytes).toBe(0xcafebabe);
          expect(reader.maxOffset).toBe(126);
        });
      });

    });

  }());