Test First React part 1: setup and first tests

React is a great choice for writing test first client side Javascript. The test ecosystem is mature enough to enable test first development of complex components. This article shows how to build a React component test first and introduces supporting test libraries Jest and Enzyme. In the next article we’ll look at more advanced testing including API testing and module mocking.

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Test log4j2 with JUnit using a custom appender

In previous articles, I’ve described how to test System.out with JUnit and how to test log4j with JUnit. This article describes how to test log4j2 logging with JUnit. This largely follows the same technique as testing log4j logging but using the the newer log4j2 APIs. Differences between log4j and log4j2 log4j2 follows a similar design read more »

Test log4j with JUnit using a custom appender

Following a recent article on how to Test System.out with JUnit, here’s a follow up on how to test log4J with JUnit. This article describes a technique to test log4J output in a JUnit test by adding a custom appender. This allows us to verify that log4j output contains expected Strings.

Validate JSPs at build time

JSPs compile to Java code at run time. This is helpful if we want to test code changes without a build and deploy. However, if errors are introduced, they may not be spotted till it’s too late. A useful compromise is to validate JSPs at build time to verify that they will compile. The validator catches syntax errors before the application deploys and starts. This speeds up our build and test cycle and prevents silly mistakes slipping through to production code.

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Thymeleaf and Spring Security

Thymeleaf is a popular templating engine, particularly with Spring projects. Spring Boot has chosen Thymeleaf as the view technology of choice, largely replacing the need for JSP. With old JSPs, custom tag libraries provided integration with various technologies, including Spring Security. A similar library exists to integrate Thymeleaf and Spring Security – the Thymeleaf Spring read more »

Test System.out with JUnit

It can be useful to verify output to System.out in a unit test. For example, if you’re testing application logging or if you’re using log output to sense some other behaviour. It can be tricky to properly mock behaviour of System.out but fortunately, it is possible to test System.out using JUnit.

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Spring Boot Actuator Trace: Logging HTTP requests

Spring Boot Actuator provides assistance for application monitoring. Out of the box it provides information on application health, configuration and logging. It’s trivial to enable: simply add the spring-boot-starter-actuator dependency to a Spring Boot project in Maven or Gradle and it just works! The monitoring information is provided as JSON from HTTP endpoints or via JMX.

The Spring Boot Actuator trace endpoint is particularly handy. By default it shows the last 100 HTTP requests made to the application. This article walks through an Actuator demo and shows some of the configuration options to get the best from this feature.

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Tomcat debugging in Docker

Like a many things in Tomcat, there are a number of ways to enable remote debugging. Here’s the easiest way I’ve found to enable remote debugging in a Docker container running Tomcat.

Activate the Docker Maven plugin when Docker is present

The wonderful docker-maven-plugin from Spotify is a great way to build Docker images from Maven. If you bind it to Maven phases, it can be used to make a one-step build of a project artifact and its Docker image. For example, if you bind the Docker Maven plugin’s build goal to the Maven package phase, read more »

Spring Boot as a Windows Service

The documentation provided by Spring on deploying a Spring Boot application as a Windows Service is a little sparse. Indeed, here it is in full:

Spring Boot application can be started as Windows service using winsw.

A sample maintained separately to the core of Spring Boot describes step-by-step how you can create a Windows service for your Spring Boot application.

— From Spring Boot Reference Guide (version 1.4.3), section 56.2: Microsoft Windows Services

As the official reference guide is lacking detail, here is a step by step guide to building and deploying a Spring Boot application as a Windows Service.

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