Javascript 如何用Jasmine编写文件阅读器测试?
我试图让这个测试正常工作,但我不知道如何用FileReader编写测试。这是我的密码Javascript 如何用Jasmine编写文件阅读器测试?,javascript,html,unit-testing,jasmine,Javascript,Html,Unit Testing,Jasmine,我试图让这个测试正常工作,但我不知道如何用FileReader编写测试。这是我的密码 function Uploader(file) { this.file = file; } Uploader.prototype = (function() { function upload_file(file, file_contents) { var file_data = new FormData() file_data.append('filen
function Uploader(file) {
this.file = file;
}
Uploader.prototype = (function() {
function upload_file(file, file_contents) {
var file_data = new FormData()
file_data.append('filename', file.name)
file_data.append('mimetype', file.type)
file_data.append('data', file_contents)
file_data.append('size', file.size)
$.ajax({
url: "/upload/file",
type: "POST",
data: file_contents,
contentType: file.type,
success: function(){
// $("#thumbnail").attr("src", "/upload/thumbnail");
},
error: function(){
alert("Failed");
},
xhr: function() {
myXhr = $.ajaxSettings.xhr();
if(myXhr.upload){
myXhr.upload.addEventListener('progress',showProgress, false);
} else {
console.log("Upload progress is not supported.");
}
return myXhr;
}
});
}
return {
upload : function() {
var self = this,
reader = new FileReader(),
file_content = {};
reader.onload = function(e) {
file_content = e.target.result.split(',')[1];
upload_file(self.file, file_content);
}
}
};
})();
这是我的测试
describe("Uploader", function() {
it("should upload a file successfully", function() {
spyOn($, "ajax");
var fakeFile = {};
var uploader = new Uploader(fakeFile);
uploader.upload();
expect($.ajax.mostRecentCall.args[0]["url"]).toEqual("/upload/file");
})
});
但是它永远不会到达
reader.onload
这里的问题是reader.onload
的使用,这很难测试。您可以使用reader.addEventListener
来监视全局FileReader对象并返回模拟:
eventListener = jasmine.createSpy();
spyOn(window, "FileReader").andReturn({
addEventListener: eventListener
})
然后您可以自己启动onload回调:
expect(eventListener.mostRecentCall.args[0]).toEqual('load');
eventListener.mostRecentCall.args[1]({
target:{
result:'the result you wanna test'
}
})
此语法在2.0中更改。下面的代码给出了一个基于Andreas Köberle的答案但使用新语法的示例
// create a mock object, its a function with some inspection methods attached
var eventListener = jasmine.createSpy();
// this is going to be returned when FileReader is instantiated
var dummyFileReader = { addEventListener: eventListener };
// pipe the dummy FileReader to the application when FileReader is called on window
// this works because window.FileReader() is equivalent to new FileReader()
spyOn(window, "FileReader").and.returnValue(dummyFileReader)
// your application will do something like this ..
var reader = new FileReader();
// .. and attach the onload event handler
reader.addEventListener('load', function(e) {
// obviously this wouldnt be in your app - but it demonstrates that this is the
// function called by the last line - onloadHandler(event);
expect(e.target.result).toEqual('url');
// jasmine async callback
done();
});
// if addEventListener was called on the spy then mostRecent() will be an object.
// if not it will be null so careful with that. the args array contains the
// arguments that addEventListener was called with. in our case arg[0] is the event name ..
expect(eventListener.calls.mostRecent().args[0]).toEqual('load');
// .. and arg[1] is the event handler function
var onloadHandler = eventListener.calls.mostRecent().args[1];
// which means we can make a dummy event object ..
var event = { target : { result : 'url' } };
// .. and call the applications event handler with our test data as if the user had
// chosen a file via the picker
onloadHandler(event);
我发现自己下一步最容易做
- 模拟blob文件
- 在测试环境中运行reader.onload
//控制器
$scope.handleFile=函数(e){
var f=e[0];
$scope.myFile={
姓名:“,
大小:“,
base64:“
};
var reader=new FileReader();
reader.onload=函数(e){
试一试{
var buffer=e.target.result;
$scope.myFile={
姓名:f.name,
尺寸:f.size,
base64:XLSX.arrayBufferToBase64(缓冲区)
};
$scope.$apply();
}捕获(错误){
$scope.error=“error!”;
$scope.$apply();
}
};
reader.readAsArrayBuffer(f);
//在测试环境中运行
if(typeof jasmine=='object'){reader.onload(e)}
}
//茉莉花试验
它('handleFile 0',函数(){
var fileContentsEncodedInHex=[“\x45\x6e\x63\x6f\x64\x65\x49\x6e\x48\x65\x78\x42\x65\x63\x61\x75\x73\x61\x62\x69\x6e\x61\x72\x79\x46\x69\x6c\x65\x73\x73\x63\x6f\x6e\x64\x61\x69\x65\x65\x64\x61\x61\x62\x62\x65\x61\x61\x61\x61\x61\x62\x61\x63\x61\x61\x63\x62\x62\x63\x62\x61”];
var blob=新blob(fileContentsEncodedInHex);
blob.type='application/zip';
blob.name='name';
blob.size=11111;
var e={0:blob,目标:{result:{};
$scope.handleFile(e);
expect($scope.error).toEqual(“”);
});代码>我也面临类似的问题,并且能够在不使用addeventlistener的情况下实现它。我使用了onloadend,下面是我所做的。
我的ts文件包含以下代码:-
let reader = new FileReader();
reader.onloadend = function() {
let dataUrl = reader.result;
// Some working here
};
reader.readAsDataURL(blob);
我的规范文件(测试)案例代码:-
let mockFileReader = {
result:'',
readAsDataURL:(blobInput)=> {
console.log('readAsDataURL');
},
onloadend:()=> {
console.log('onloadend');
}
};
spyOn<any>(window, 'FileReader').and.returnValue(mockFileReader);
spyOn<any>(mockFileReader, 'readAsDataURL').and.callFake((blobInput)=> {
// debug your running application and assign to "encodedString" whatever
//value comes actually after using readAsDataURL for e.g.
//"data:*/*;base64,XoteIKsldk......"
mockFileReader.result = encodedString;
mockFileReader.onloadend();
});
让mockFileReader={
结果:“”,
readAsDataURL:(blobInput)=>{
log('readAsDataURL');
},
onloadend:()=>{
log('onloadend');
}
};
spyOn(窗口,'FileReader')。和.returnValue(mockFileReader);
spyOn(mockFileReader,'readAsDataURL')。和.callFake((blobInput)=>{
//调试正在运行的应用程序,并将其分配给“encodedString”
//值实际上是在使用readAsDataURL之后出现的,例如。
//“数据:*/*;base64,XoteIKsldk…”
mockFileReader.result=encodedString;
mockFileReader.onloadend();
});
通过这种方式,您模拟了FileReader对象,并返回了对您自己的“readAsDataURL”的假调用。因此,现在当您的实际代码调用“reasAsDataURL”时,您的伪函数被调用,其中您在“result”中分配了一个编码字符串,并调用了“onloadend”函数,您已经在代码(.ts)文件中分配了一个功能。因此,它会被调用,并得到预期的结果。
希望能有所帮助。当从readAsDataURL
调用onloadend时,我努力想知道如何测试它。
这是一堆我最后得到的东西
生产代码:
测试代码:
我认为最好的方法是使用真正的文件阅读器
(不要模仿它),并传入真正的文件
或Blob
。这提高了您的测试覆盖率,并使您的测试不那么脆弱
如果你的测试没有在IE中运行,你可以使用
const fakeFile=新文件([“某些内容”],“File.txt”,{type:“text/plain”});
如果您需要与IE兼容,您可以构造一个并使其看起来像一个文件:
const fakeFile=newblob([“某些内容]);
fakeFile.name=“file.txt”;
fakeFile.type=“text/plain”;
FileReader
可以读取这两个对象中的任何一个,因此无需对其进行模拟。我对此束手无策。谁能提供一个有效的例子?我总是不确定(使用Karma/Angular/Jasmine)。这真的很过时。现在我认为最好不要嘲笑FileReader,请参见下面的答案。我发现,奇怪的是,如果你在全局范围内隐式创建FileReader,比如new FileReader()
,Jasmine找不到它,但是,如果我调用newwindow.FileReader()
,那么间谍就会像预期的那样出现。我花了将近一个小时才弄明白。@supertguy我恐怕不记得了。很抱歉我今天一直在努力解决这个问题,而你的解决方案确实让问题变得简单多了。谢谢如果要测试onerror
路径,该怎么办?你会怎么做呢?我不确定这是否可能——你可能需要从其他答案中选择一种嘲弄的方法。
loadFileDataIntoChargeback(tempFileList) {
var fileNamesAndData = [];
for (var i = 0, f; f = tempFileList[i]; i++) {
let theFile = tempFileList[i];
var reader = new FileReader();
reader.onloadend = ((theFile) => {
return (fileData) => {
var insertionIndex = this.chargeback.fileList.length;
this.chargeback.fileList.push({ FileName: theFile.name, Data: fileData.target.result, FileType: theFile.type });
this.loadFilePreviews(theFile, insertionIndex);
}
})(f);
reader.readAsDataURL(f);
}
this.fileInputPath = "";
}
describe('when the files are loaded into the chargeback', () => {
it('loads file previews', () => {
let mockFileReader = {
target: { result: '' },
readAsDataURL: (blobInput) => {},
onloadend: () => {}
};
spyOn(chargeback, "loadFilePreviews");
spyOn(window, 'FileReader').and.returnValue(mockFileReader);
spyOn(mockFileReader, 'readAsDataURL').and.callFake((blobInput) => {
mockFileReader.onloadend({ target: { result: "data:image/jpeg;base64,/9j/4QAYRXh" } });
});
var readFileList = chargeback.getArrayFromFileInput([getImageFile1()]);
chargeback.loadFileDataIntoChargeback(readFileList);
expect(chargeback.loadFilePreviews).toHaveBeenCalled();
});
});