JUnit best practices inwards Java
No uncertainty writing good JUnit assay cases is a rare science only similar writing expert Code. Influenza A virus subtype H5N1 good, good thought too well-written JUnit assay tin forbid several production issues during initial evolution or afterwards maintenance inwards Java application. Though ane tin solely travel perfect inwards writing JUnit assay yesteryear practise too a score of concern noesis which is of import to envision dissimilar scenarios on which a method gets called, approximately best practices or sense of approximately other developer may assist to guide other programs. In this Java article, I am sharing approximately JUnit tips too JUnit best practices which I direct maintain learned too follow piece writing unit tests using JUnit for Java programs. One of the books which helped me a lot is Pragmatic Unit Testing inwards Java alongside JUnit by Andrew Hunt too Dave Thomas, This mass shares a lot of JUnit best practices which are worth reading too learning if y'all are serious almost Unit testing using JUnit.
Never undermine the importance of automated testing too assay cases written yesteryear Developer who writes the code too that's the argue many companies are quest programmers to design, code too supply unit of measurement tests during their Java interviews. These JUnit best practices non only apply to JUnit but to whatever other testing framework every bit good similar TestNG, they are to a greater extent than on testing too writing assay cases which are to a greater extent than of import science than tools similar JUnit or TestNG.
Never undermine the importance of automated testing too assay cases written yesteryear Developer who writes the code too that's the argue many companies are quest programmers to design, code too supply unit of measurement tests during their Java interviews. These JUnit best practices non only apply to JUnit but to whatever other testing framework every bit good similar TestNG, they are to a greater extent than on testing too writing assay cases which are to a greater extent than of import science than tools similar JUnit or TestNG.
Junior Best practices
Here is a listing of 10 JUnit best practices I direct maintain compiled , As I said these best practices are related to testing, thinking assay cases too writing assay cases rather than focusing on JUnit features similar Testing Exception or Timeout.
1) It's non practically possible to acquire 100% code coverage, hence don't aim to write unit of measurement tests for each method too footling operations, instead, write unit of measurement tests for a method which is probable to direct maintain bugs during maintenance. Always tests meat method too meat classes which are used heavily yesteryear dissimilar parts of a program. If y'all follow this best practise piece writing test, y'all volition travel surprised alongside the lineament of code, it oft outcome inwards fewer bugs during the formal testing cycle.
1) It's non practically possible to acquire 100% code coverage, hence don't aim to write unit of measurement tests for each method too footling operations, instead, write unit of measurement tests for a method which is probable to direct maintain bugs during maintenance. Always tests meat method too meat classes which are used heavily yesteryear dissimilar parts of a program. If y'all follow this best practise piece writing test, y'all volition travel surprised alongside the lineament of code, it oft outcome inwards fewer bugs during the formal testing cycle.
2) Integrate Junit tests alongside your construct script hence that alongside every compile your tests run automatically. Maven too ANT 2 most pop construct technology scientific discipline for Java application provides back upwards to run Junit tests. This is non only a best practise but a criterion of edifice Java application. Always run assay cases piece edifice projects this non solely verifies novel code but also alarm alongside whatever potential mistake which results due to recent changes. Sometimes piece fixing a põrnikas developer innovate approximately other põrnikas if y'all direct maintain JUnit assay integrated alongside the construct or next CI practices hence y'all are ameliorate to prepare to bargain alongside them.
3) Develop assay cases based on usage too boundary conditions, This is my favorite Junit assay practise too to a greater extent than oft than non asked every bit interview query on JUnit every bit well. For example, if y'all are asked to write a role to supplant all occurrence of a given character from String e.g.
public String replace(String text, char ch){ …}
How volition y'all write a assay instance for that? to my surprise many Java plan commencement focusing on JUnit assay syntax similar setUp() too tearDown() fifty-fifty earlier thinking of actual assay scenarios similar :
1) Test for empty text or empty character?
2) Test for the grapheme which is non inwards String?
3) Test for characters which comes during start, halt or pump of String?
4) Test to encompass if text String contains only ane grapheme which is equal or non equal to the replaced one?
5) Test alongside String contains only contains ane grapheme multiple time?
These are only a few of assay cases I tin think of but the thought is to focus on what to test too non how to test, most IDE similar Eclipse too Netbeans volition accept aid of that. Though y'all should direct maintain basic Idea of essential functionality of JUnit testing similar how to assay Exceptions, Timeout etc.
4) Make certain your JUnit assay are aligned alongside your concern requirement specified inwards BRD or Business Requirement document.
5) Write a assay for the non functional requirement every bit well, similar piece writing a Thread condom class, it's of import to write tests which tries to pause thread-safety.
6) If a role or method depends on upon the club of events hence brand certain your JUnit assay covers ordering requirement too my accept is to assay both sides of the money agency alongside right ordering method should attain right outcome too alongside wrong ordering, it should throw Exception or confirms the choice operation.another JUnit best practise which is worth remembering.
7) One Idea which helps me piece writing unit of measurement assay is to do dummy tests piece working alongside requirements because that’s the best fourth dimension y'all yell back requirements too having a assay instance alongside a comment that depict intent of assay let’s y'all to implement it afterwards or only lay @Ignore if y'all don’t direct maintain fourth dimension to implement assay too using Junit4 annotations. This helps me to encompass most of the requirement piece writing code every bit good every bit test. this only enforces y'all to write every bit many assay instance every bit defined yesteryear requirements.
building your application. every bit unit of measurement tests run automatically during construct process, they are required to complete early too footling unit of measurement assay only adds on fourth dimension too enshroud to a greater extent than useful instance to run later.
9) Keep your Unit assay independent of Environmental data similar Database, File System etc. The unit of measurement assay depends on environmental information may piece of work inwards approximately surroundings too may non piece of work on other. It's a expert thought to occupation a carefully chosen laid of information embedded inwards assay cases every bit good every bit a placeholder method which tin travel plugged to database if required using configuration.
10) Use available tools similar DBunit, XMLUnit too Spring assay framework based upon your projection too your need.
In Summary code review too Unit testing is every bit vital every bit writing expert code too good comments. Think through requirement piece writing assay cases too focus on scenarios. I promise these JUnit too testing best practices volition assist y'all to write ameliorate code.
Further Learning
Unit Testing In Java With JUnit
JUnit too Mockito Crash Course
Learn Unit Testing alongside Junit & Mockito inwards xxx Steps