Angular Karma Jasmine - test function

Basically i have to test this below function, where i'm reading from text file

$window.resolveLocalFileSystemURL(cordova.file.dataDirectory, function (dir) {     var path = 'somefile.txt';                         dir.getFile(path, { create: true }, function (file) {         file.file(function (file) {             var reader = new FileReader();             reader.onloadend = function () {                                                resolve(this.result);             }             reader.readAsText(file);         });     }, error);  }, error); 

i'm stuck in writing the unit test cases for reading file

describe('get data from file', function () {                  it('should read the files from the data', function () {         var syncFile = 'somefile.txt';          expect( ).toBe( );     }); }); 

How to write unit test for filereader for reading the file? PS : i'm new to unit testing using karma

1 Answers

Answers 1

You should not use FileReader directly. Change that line to

var reader = new $window.FileReader(); 

In your test mock the $window and return a custom FileReader object. Then do the tests on that. Something like below.

describe('get data from file', function () {      var $window, fileReader;      beforeEach(function () {          inject(function (_$window_) {             $window = _$window_;         });          fileReader = function () {             return {};         };          spyOn($window, "FileReader").and.returnValue(fileReader);     });      it('should read the files from the data', function () {         var syncFile = 'somefile.txt';          expect($window.FileReader).toHaveBeenCalled();    }); }); 

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