How do I mock javax.sql.DataSource

By LiBePosted on Friday 31 July 2020Friday 31 July 2020Cat G33k, ProgrammesLeave a comment

This is the annoying question I have had to ask myself. Integration tests are pretty slow. Even when they use a dedicated database like H2 or Derby, they are still accessing dark infrastructure software layers to read / edit / write / flush data. I was wanting tests able to run in no time and… Read More »

How to write a machine learning program

By LiBePosted on Saturday 30 May 2020Monday 1 June 2020Cat G33k, ProgrammesLeave a comment

Artificial Intelligence, Machine learning, Data science... There are plenty of names for defining one of the most trendy topic in IT companies today. Using powerful solutions won't make you (and me) a specialist or a data scientist. Even if we are trained enough with these solutions. I wanted to allow me some time to create… Read More »

How do car drivers drive ?

By LiBePosted on Thursday 30 April 2020Thursday 30 April 2020Cat G33k, ProgrammesLeave a comment

That is what I have been wondering, how would I write a program able to adapt my speed to not crush the next obstacle in front of me ? Before thinking of machine learning algorithms that can learn from tricky situations (pedestrian crossing the street without looking or plane landing on the road), we can… Read More »

Unit Testing the ExceptionHandler

By LiBePosted on Tuesday 31 March 2020Tuesday 31 March 2020Cat G33k, ProgrammesLeave a comment

Sometimes you just fight against adding SpringBootTest when it comes to asserting the API responses. - SpringBootTest are slow, they sometimes require to start an entire infrastructure (databases, JMS connections) to only simulate two or three interactions - You want your tests to be predictive and to run the very method in the controller you… Read More »

Build an exercise git repository with stage branches

By LiBePosted on Saturday 29 February 2020Saturday 29 February 2020Cat G33k, ProgrammesLeave a comment

You may want to build separately several branches of your repository with different contents in each "stage" of your exercise. For example stage-0 will contain the begining of the exercise and each stage-$i will incrementally add some implementations and exercise corrections. The thing that is uncomfortable when these stages are on the same commit tree… Read More »

Faked out DynamoDBMapper

By LiBePosted on Friday 31 January 2020Friday 31 January 2020Cat G33k, ProgrammesLeave a comment

Wanna try DynamoDB without using your network interface ? Not requiring connection will allow any developer on any platform to run your tests without setup pain or docker installation. Below is a mapper able to do the two most basic operations necessary to read and write data : save and query. You will be able… Read More »

A naive credit card number validator

By LiBePosted on Tuesday 31 December 2019Tuesday 31 December 2019Cat G33k, ProgrammesLeave a comment

Of course, validating a credit card is not something we can do in a browser. If we did, we could get valid card numbers that don't match any account. The purpose of this post is then not to validate the card with the issuer, but to help the user to make sure that he did… Read More »

Ship modules without moment.js

By LiBePosted on Saturday 30 November 2019Saturday 30 November 2019Cat G33k, ProgrammesLeave a comment

Moment.js is a great and comprehensive library to use date, times, and formatting. Why should we use it ? Because the Date interface in javascript is lacking of flexibility. It also permits to to translate a moment in a any locale and language. Why should not we use it ? 232 kB (or 66 kB… Read More »

GraphQL in Kotlin : how to register generic scalars without sweating

By LiBePosted on Thursday 31 October 2019Thursday 31 October 2019Cat G33k, ProgrammesLeave a comment

If you are working like I do, you certainly are wrapping the smallest pieces of data to ensure they follow strict validation rules.And you are likely to wrap the small field values in wrapping type, for these reasons : - your IDE will tell you that you are manipulating an EmailAddress, an IPAddressV6 or a… Read More »

The no-breaking-change API

By LiBePosted on Monday 30 September 2019Monday 30 September 2019Cat G33k, ProgrammesLeave a comment

Ever thought of changing the API contract without having to ask for any upgrade ? Without waiting for all the consumers to adapt their client ? There is one technique that allow you to build backward compatible contracts, and it does not need versioning nor any deprecation strategy. What is it ? Just make good… Read More »