As a developer sooner or later you will encounter bugs, be it small ones or production breaking bugs. Now it is your task to find and fix the bug as soon as possible. In this article I will list the techniques I learned over the course of many years debugging web applications in the hope that it will help you be better and more efficient in bug hunting.

Op de eerste volledige conferentie dag van JavaOne stond natuurlijk meteen de keynote gepland. Het eerste gedeelte van de keynote werd verzorgd door de hoofdsponsor Intel en was best vermakelijk al lag de salespitch er wel dik bovenop. Intel lanceerde 2 opensource producten voor de Java community:

When we write a list in Asciidoctor we can simply create a list item by starting the line with a dot (.). To create a another list item we simply start a new line with a dot (.). But what if we want to add a list item with multiple paragraphs, or text and a source code block element. We can use the list item continuation (+) to indicate to Asciidoctor we want to keep these together for a single list item.

In the following example we have a list in Asciidoctor markup. The second list item has multiple paragraphs , the third item has an extra admonition block and the fourth item contains a source code block:

Writing a parameterized specification in Spock is easy. We need to add the where: block and use data providers to specify different values. For each set of values from the data providers our specifications is run, so we can test for example very effectively multiple input arguments for a method and the expected outcome. A data provider can be anything that implements the Iterable interface. Spock also adds support for a data table. In the data table we define columns for each variable and in the rows values for each variable. Since Spock 1.1 we can reuse the value of the variables inside the data provider or data table. The value of the variable can only be reused in variables that are defined after the variable we want to reuse is defined.

In the following example we have two feature methods, one uses a data provider and one a data table. The variable sentence is defined after the variable search, so we can use the search variable value in the definition of the sentence variable.

We all know writing tests or specifications with Spock is fun. We can run our specifications and when one of our assertions in a feature method invalid, the feature method is marked as failed. If we have more than one assertion in our feature method, only the first assertion that fails is returned as an error. Any other assertion after a failing assertion are not checked. To let Spock execute all assertions and return all failing assertions at once we must use the verifyAll method. We pass a closure with all our assertions to the method. All assertions will be checked when use the verifyAll and if one or more of the assertions is invalid the feature method will fail.

In the following example specification we have 3 assertions in the feature method check all properties are valid. We don’t use the verifyAll method in our first example.

As all who have used it know Selenium is a powerful tool when testing front-end applications. I personally use it in combination with protractor. This is because most of the work I do is with Angular and AngularJS applications. When you are using Typescript extending classes is an easy thing. In light of this I’ve been experimenting with new approaches to creating page objects.

As someone who spends quite some time writing and checking unit and e2e tests I’ve started noticing a trend I’m somewhat confused by. There have been multiple occasions in which I’ve encountered test logic (repeatable and single use) in either test specifications or page objects. So I decided to share my approach to writing and foremost separating my test code into three categories. Those being: Specifications , Sequences and Page Objects. I’ll describe my views on these categories below.

I’d like to start with the following service announcement,

When I started using TypeScript for my Angular applications, I was confused about all the different ways with which you could import other modules. import './polyfills.ts'; import { Component } from '@angular/core'; import HomeComponent from './pages/home/home-page.component'; import * as _ from 'lodash'; import assert = require('assert'); At first, I thought that as a programmer you could choose whether you wanted to use curly braces or not, but I quickly found out that that was not the case. It all depends on how the module that you are importing is structured. I have created an overview of the different ways by which a module can be exported, together with their corresponding import syntax. Most of them are actually plain ECMAScript 2015 (ES6) module syntax that TypeScript uses as well. The examples are from my solution to the first puzzle of Advent of Code 2016 and can be found on GitHub if you want to play around with imports and exports yourself.

Writing unit tests for our handlers in Ratpack is easy with RequestFixture. We invoke the handle method and use a Handler or Chain we want to test as argument. We can provide extra details on the fixture instance with a second argument, for example adding objects to the registry or setting the request method. The handle method returns a HandlingResult object. This object has the method exception that we can use to see if an exception occurred in our code under test. The method throws a HandlerExceptionNotThrownException if the expected exception doesn’t occur.

In the following example we have two feature methods to check if an exception occurred or not:

Sometimes we are working on a new feature in our code and we want to write a specification for it without yet really implementing the feature. To indicate we know the specification will fail while we are implementing the feature we can add the @PendingFeature annotation to our specification method. With this annotation Spock will still execute the test, but will set the status to ignored if the test fails. But if the test passes the status is set to failed. So when we have finished the feature we need to remove the annotation and Spock will kindly remind us to do so this way.

In the following example specification we use the @PendingFeature annotation: