Warszawska Grupa Użytkowników Technologii Java (WJUG) ma nową
stronę internetową. Kod i layout strony przygotował TouK i przekazał grupie. Niech służy! Cieszymy się, że mogliśmy przyczynić się w ten sposób do budowy javowej społeczności.
Warszawska Grupa Użytkowników Technologii Java (WJUG) ma nową
stronę internetową. Kod i layout strony przygotował TouK i przekazał grupie. Niech służy! Cieszymy się, że mogliśmy przyczynić się w ten sposób do budowy javowej społeczności.
Micro services could be a buzzword of 2014 for me. Few months ago I was curious to try Dropwizard framework as a separate backend, but didn’t get the whole idea yet. But then I watched a mind-blowing “Micro-Services Architecture” talk by Fred George. Also, the 4.0 release notes of Spring covers microservices as an important rising trend as well. After 10 years of having SOA in mind, but still developing monoliths, it’s a really tempting idea to try to decouple systems into a set of independently developed and deployed RESTful services.
Micro services could be a buzzword of 2014 for me. Few months ago I was curious to try Dropwizard framework as a separate backend, but didn’t get the whole idea yet. But then I watched a mind-blowing “Micro-Services Architecture” talk by Fred George. Also, the 4.0 release notes of Spring covers microservices as an important rising trend as well. After 10 years of having SOA in mind, but still developing monoliths, it’s a really tempting idea to try to decouple systems into a set of independently developed and deployed RESTful services.
Being a Java developer is kinda hard these days. Java may not be dead yet, but when keeping in sync with all the hipster JavaScript frameworks could make us feel a bit outside the playground. It’s even hard to list JavaScript frameworks with latest releases on one website.
In my current project, we are using AngularJS. It’a a nice abstraction of MV* pattern in frontend layer of any web application (we use Grails underneath). Here is a nice article with an 8-point Win List of Angular way of handling AJAX calls and updating the view. So it’s not only a funny new framework but a truly helper of keeping your code clean and neat.
But there is also another area when you can put helpful JS framework in place of plan-old-java one - functional tests. Especially when you are dealing with one page app with lots of asynchronous REST/JSON communication.
In Java/JVM project the typical is to use Selenium with some wrapper like Geb. So you start your project, setup your CI-functional testing pipeline and… after 1 month of coding your tests stop working and being maintainable. The frameworks itselves are not bad, but the typical setup is so heavy and has so many points of failure that keeping it working in a real life project is really hard.
Here is my list of common myths about Selenium: * It allows you to record test scripts via handy GUI - maybe some static request/response sites. In modern web applications with asynchronous REST/JSON communication your tests must contain a lot of “waitFor” statements and you cannot automate where these should be included. * It allows you to test your web app against many browsers - don’t try to automate IE tests! You have to manually open your app in IE to see how it actually bahaves! * It integrates well with continuous integration servers like Jenkins - you have to setup Selenium Grid on server with X installed to run tests on Chrome or Firefox and a Windows server for IE. And the headless HtmlUnit driver lacks a lot of JS support.
So I decided to try something different and introduce a bit of JavaScript tooling in our project by using CasperJS.
CasperJS is simple but powerful navigation scripting & testing utility for PhantomJS - scritable headless WebKit (which is an rendering engine used by Safari and Chrome). In short - CasperJS allows you to navigate and make assertions about web pages as they’d been rendered in Google Chrome. It is enough for me to automate the functional tests of my application.
If you want a gentle introduction to the world of CasperJS I suggest you to read: * Official website, especially installation guide and API * Introductionary article from CasperJS creator Nicolas Perriault * Highlevel testing with CasperJS by Kevin van Zonneveld * grails-angular-scaffolding plugin by Rob Fletcher with some working CasperJS tests
I run my test suite via following script:
casperjs test --direct --log-level=debug --testhost=localhost:8080 --includes=test/casper/includes/casper-angular.coffee,test/casper/includes/pages.coffee test/casper/specs/
casper-angular.coffe
casper.test.on "fail", (failure) ->
casper.capture(screenshot)
testhost = casper.cli.get "testhost"
screenshot = 'test-fail.png'
casper
.log("Using testhost: #{testhost}", "info")
.log("Using screenshot: #{screenshot}", "info")
casper.waitUntilVisible = (selector, message, callback) ->
@waitFor ->
@visible selector
, callback, (timeout) ->
@log("Selector [#{selector}] not visible, failing")
withParentSelector selector, (parent) ->
casper.log("Output of parent selector [#{parent}]")
casper.debugHTML(parent)
@echo message, "RED_BAR"
@capture(screenshot)
@test.fail(f("Wait timeout occured (%dms)", timeout))
withParentSelector = (selector, callback) ->
if selector.lastIndexOf(" ") > 0
parent = selector[0..selector.lastIndexOf(" ")-1]
callback(parent)
Sample pages.coffee:
x = require('casper').selectXPath
class EditDocumentPage
assertAt: ->
casper.test.assertSelectorExists("div.customerAccountInfo", 'at EditDocumentPage')
templatesTreeFirstCategory: 'ul.tree li label'
templatesTreeFirstTemplate: 'ul.tree li a'
closePreview: '.closePreview a'
smallPreview: '.smallPreviewContent img'
bigPreview: 'img.previewImage'
confirmDelete: x("//div[@class='modal-footer']/a[1]")
casper.editDocument = new EditDocumentPage()
End a test script:
testhost = casper.cli.get "testhost" or 'localhost:8080'
casper.start "http://#{testhost}/app", ->
@test.assertHttpStatus 302
@test.assertUrlMatch /\/fakeLogin/, 'auto login'
@test.assert @visible('input#Create'), 'mock login button'
@click 'input#Create'
casper.then ->
@test.assertUrlMatch /document#\/edit/, 'new document'
@editDocument.assertAt()
@waitUntilVisible @editDocument.templatesTreeFirstCategory, 'template categories not visible', ->
@click @editDocument.templatesTreeFirstCategory
@waitUntilVisible @editDocument.templatesTreeFirstTemplate, 'template not visible', ->
@click @editDocument.templatesTreeFirstTemplate
casper.then ->
@waitUntilVisible @editDocument.smallPreview, 'small preview not visible', ->
# could be dblclick / whatever
@mouseEvent('click', @editDocument.smallPreview)
casper.then ->
@waitUntilVisible @editDocument.bigPreview, 'big preview should be visible', ->
@test.assertEvalEquals ->
$('.pageCounter').text()
, '1/1', 'page counter should be visible'
@click @editDocument.closePreview
casper.then ->
@click 'button.cancel'
@waitUntilVisible '.modal-footer', 'delete confirmation not visible', ->
@click @editDocument.confirmDelete
casper.run ->
@test.done()
Here is a list of CasperJS features/caveats used here:
--direct --log-level=debug
from commandline for best results. Logging is essential here since Phantom often exists without any error and you do want to know what just happened.--includes
switch.log
statement. In my version I also look for a parent selector and debugHTML
the content of it - great for debugging what is actually rendered by the browser.@editDocument.assertAt()
.:first
and :last
selectors. I cannot get them working (but maybe I’m doing something wrong?). But in CasperJS you can also use XPath selectors which are fine for matching n-th child of some element (x("//div[@class='modal-footer']/a[1]")
).
:first
and :last
are not CSS3 selectors, but JQuery ones. Here is a list of CSS3 selectors, all of these are supported by CasperJS. So you can use nth-child(1)
is this case. Thanks Andy and Nicolas for the comments!Working with CasperJS can lead you to a few hour stall, but after getting things working you have a new, cool tool in your box!