#scalacheck

[dev-snack]

Intro to ScalaCheck

[reportwire]

From TDD to PBT via Kotest

From TDD to PBT via Kotest

In this post, we see how to integrate PBT into your Kotlin tests. Introduction I’ve been a big fan of Property Based Testing for a number of years, based on my experiences with ScalaCheck. It’s always been an annoyance that Kotlin did not support this testing style, at least to the same extent. There was some functionality in Kotest (formerly KotlinTest), but it paled in comparison to what was…

[softwareengineeringleader]

"This is "Scala Italy 2018 - Daniela Sfregola - Random data generation with Scalacheck" by Scala Italy on Vimeo, the home for high quality videos and the…". Reblog with caption 🙃

[qoholiccom]

Scala developer

Job Title: Scala Developer Location: Bentonville, AR Duration: Longterm Job Description: Excellent problem-solving, communication and analytical skills 5 + years of experience in Strong grasp of functional programming constructs and approaches, with a focus on Scala. 2+ years of Experience with Scala 2.10 or higher, SBT, ScalaTest, ScalaCheck The Light bend Stack: Akka, Play, Slick, Akka Streams Fluency with SQL and/or NoSQL databases: Postgres, Riak, Cassandra, HBase, MongoDB, etc. Reactive programming and principles Apache Spark, Hadoop, Steam Processing Kafka, RabbitMQ, Spring Integration/Batch, Camel Web Technologies: JavaScript, Angular, jQuery, React, HTML5, CSS3 Must have Micro-services Development experience Reference : Scala developer jobs source http://www.qoholic.com/index.php?page=item&id=2640

[jobsaggregationco]

Scala developer

Job Title: Scala Developer / Platform Engineer Location: Bentonville, AR Duration: Longterm Job Description: Excellent problem-solving, communication and analytical skills 5 + years of experience in Strong grasp of functional programming constructs and approaches, with a focus on Scala. 2+ years of Experience with Scala 2.10 or higher, SBT, ScalaTest, ScalaCheck The Light bend Stack: Akka, Play, Slick, Akka Streams Fluency with SQL and/or NoSQL databases: Postgres, Riak, Cassandra, HBase, MongoDB, etc. Reactive programming and principles Apache Spark, Hadoop, Steam Processing Kafka, RabbitMQ, Spring Integration/Batch, Camel Web Technologies: JavaScript, Angular, jQuery, React, HTML5, CSS3 Must have Micro-services Development experience Reference : Scala developer jobs source http://jobsaggregation.com/jobs/technology/scala-developer_i2121

[jobrealtimeco]

Scala developer

Job Title: Scala Developer / Platform Engineer Location: Bentonville, AR Duration: Longterm Job Description: Excellent problem-solving, communication and analytical skills 5 + years of experience in Strong grasp of functional programming constructs and approaches, with a focus on Scala. 2+ years of Experience with Scala 2.10 or higher, SBT, ScalaTest, ScalaCheck The Light bend Stack: Akka, Play, Slick, Akka Streams Fluency with SQL and/or NoSQL databases: Postgres, Riak, Cassandra, HBase, MongoDB, etc. Reactive programming and principles Apache Spark, Hadoop, Steam Processing Kafka, RabbitMQ, Spring Integration/Batch, Camel Web Technologies: JavaScript, Angular, jQuery, React, HTML5, CSS3 Must have Micro-services Development experience Reference : Scala developer jobs source http://jobrealtime.com/jobs/technology/scala-developer_i2121

[mrzanko]

Java Scala developer

Job Title: Java Scala Developer Location: Bentonville, AR Duration: Longterm Job Description: Excellent problem-solving, communication and analytical skills 5 + years of experience in Strong grasp of functional programming constructs and approaches, with a focus on Scala. 2+ years of Experience with Scala 2.10 or higher, SBT, ScalaTest, ScalaCheck The Light bend Stack: Akka, Play, Slick, Akka Streams Fluency with SQL and/or NoSQL databases: Postgres, Riak, Cassandra, HBase, MongoDB, etc. Reactive programming and principles Apache Spark, Hadoop, Steam Processing Kafka, RabbitMQ, Spring Integration/Batch, Camel Web Technologies: JavaScri...

Source: https://www.jobisite.com/sj/id/9037928-Java-Scala-developer

[jobisitejobsusa]

Java Scala developer

Job Title: Java Scala Developer Location: Bentonville, AR Duration: Longterm Job Description: Excellent problem-solving, communication and analytical skills 5 + years of experience in Strong grasp of functional programming constructs and approaches, with a focus on Scala. 2+ years of Experience with Scala 2.10 or higher, SBT, ScalaTest, ScalaCheck The Light bend Stack: Akka, Play, Slick, Akka Streams Fluency with SQL and/or NoSQL databases: Postgres, Riak, Cassandra, HBase, MongoDB, etc. Reactive programming and principles Apache Spark, Hadoop, Steam Processing Kafka, RabbitMQ, Spring Integration/Batch, Camel Web Technologies: JavaScri... from Job Portal https://www.jobisite.com/sj/id/9037928-Java-Scala-developer

[implicitly-notes]

kiama 2.2.0

Kiama is a Scala library for language processing including attribute grammars, term rewriting, abstract state machines and pretty printing.

This is a maintenance release with only minor changes in functionality but splits the library into two pieces for publishing.

Potentially breaking changes

Kiama is now published as two separate libraries kiama and kiama-extras with the former containing just the core Kiama functionality and the latter containing extra support that is useful in many Kiama-based applications. At the moment, the kiama-extras library contains the Compiler, Config, Console and REPL components that are useful for building command-line configurable compilers and read-eval-print loops, plus the Kiama examples. In the new scheme clients can depend on one or both of these libraries, depending on their needs. Previously you got the extras (and their dependencies) whether you wanted them or not.

Output: To match standard code formatting styles, the seq pretty-printer now doesn't include a space after the prefix. E.g., what was previously printed as Seq (1, 2, 3) will now be printed as Seq(1, 2, 3). This change is also visible via the pretty-printers any and list which are defined in terms of seq.

Bug Fixes

Rewriting: The log and logfail strategies no longer have a default emitter argument since default arguments are not allowed on macro applications.

Util: The compiler, REPL and test drivers now give a sensible message when the command-line is illegal, rather than crashing with an exception.

Util: Separate Kiama suiteSourcePath setting from that used by clients of test code. The Kiama test suites now use the KiamaTests trait that sets suiteSourcePath appropriately for Kiama. The Tests suite now sets it to be suitable for clients who are using the default Scala project setup.

Other

Move to sbt 1.1.4, Scala 2.12.5, 2.11.12, 2.10.7

Update libraries to Guava 24.1, Scallop 3.1.2, JLine 2.14.6, ScalaCheck 3.0.5, ScalaTest 1.13.5, Scallop 3.1.2

Kiama is a Scala library for language processing including parsing, attribute grammars, term rewriting, abstract state machines and pretty printing.

[scalarconf]

Scalar 2017 presentations & blogs

Hello,

thank you for attending Scalar 2017! While we are waiting for the videos and details statistics, here’s a collection of links to presentations and attendee blogs summarising their Scalar experience. We’ll be extending this list throughout the week, so if you’d like to be included, please let us know!

Presentations

"Typeclasses — a type system construct” by Andrea Lattuada

“Quark: A Purely-Functional Scala DSL for Data Processing & Analytics” by John A. de Goes

“Monad Transformers Down to Earth” by Gabriele Petronella

“Akka cluster management and split brain resolution” by Niko Will

“Anomaly detection made easy” by Piotr Guzik

“Artificial Neural Networks in Akka” by Maciej Gorywoda

“Modularity à la ML” by Ionuț G. Stan

“Random Data Generation with ScalaCheck" by Daniela Sfregola

“Case study: typelevel programming in real worls” by George Leontiev

“Taking your side effects aside“ by Tomasz Kogut

“Kontextfrei: A new approach to testable Spark applications” by Daniel Westheide

“How to extend map? Or why we need collections redesign?“ by Szymon Matejczyk

Attendee blogs about Scalar

Scalar 2017 by Bartosz Mikulski

Scalar Conference 2017 Summary by Wojciech Pituła

Scalar 2017 by Silvia Moura Pina

Scalar Conference 2017 summary by Bartosz Ocytko

[PL]Scalar 2017, czyli najmodniejszy buzz word Scali to… by Bartłomiej Kuczyński

Scalar Conf 2017 – A quick visit to Warsaw by Paulo Siqueira

[ulyss]

В вводной статье серии вы, надеюсь уже, успели познакомиться с генераторами.

[wickeds0urce]

Specs + ScalaCheck - Scala Unit testing at its best...

Testing java business logic is said to be the second least liked task in software engineering - right after documentation. However, there seems to be hope for those resistant to best-practices like test driven development (TDD) and those distracted by time consuming unit tests: testing in scala with Specs and ScalaCheck!

TDD has been a revolutionary idea and BDD, Behavior Driven Development, is the next evolutionary step! It is about the test saying what it is about... - alright, it is maybe easier to show you than explain it to you or so, as Morpheus said to Neo. Anyway, that is a snippet of BDD in Scala with Specs:

class MediaGroupServiceSpec extends Specification("MediaGroupService") with ScalaCheck { val service: IMediaGroupService = new MediaGroupService() // *** START TEST DATA GENERATORS *** val artists = for(artistName <- Gen.alphaStr) yield { val artist = new Artist() artist setName artistName artist } val albums = for(albumName <- Gen.alphaStr) yield { val album = new Album() album setTitle albumName album } val songs = for(songName <- Gen.alphaStr) yield { val song = new Song() song setTitle songName song } songs.map(_.setArtist(artists.sample.get)) songs.map(_.setAlbum(albums.sample.get)) val testSongsList = Gen.containerOf[ArrayList, Song](songs) // *** END TEST DATA GENERATORS *** "The artists list" should { "contain only 'All Artists' if there are no songs" in { val songs: java.util.Collection[Song] = new java.util.ArrayList[Song]() service initialize songs val artists: java.util.Collection[Artist] = service getArtists artists.size mustEqual 1 } "contain 'All Artists' as first artist" in { testSongsList must pass { liste: ArrayList[Song] => service initialize liste val artistsFromService = service getArtists val artistsIt: Iterator[Artist] = artistsFromService.iterator() artistsIt.next.getName mustEqual IMediaGroupService.EVERY_ARTIST } } } }

I'll explain shortly what is tested in that bunch of code: It is about a service, IMediaGroupService, which is initialized with a list of song objects and should return the list of the corresponding artists by its method getArtists. The above tests check if the label "All Artists" is the first item in the returned list... so let's get back to what makes those lines extraordinary...

Specs and ScalaCheck are two separate Scala Testing Frameworks. Why use both of them? Because both of them have their advantages: Specs behavioral touch is great (e.g.: "The artist list should contain only 'All Artists' if there are no songs" - so the test literally explains what behavior it is testing) and ScalaCheck is cool because it provides test data for your tests! This is a life-saving feature for us developers who spend boring hours to get/invent test data which tends to be unsufficient in the end!

You might wonder how the magical generation works... look at the lines in between the "START TEST DATA GENERATORS" comments: 'Gen.alphaStr' is a generator provided by ScalaCheck which returns any String you might think of. In the following for-comprehensions generators for the domain-specific java objects are created and finally, by "val testSongsList = Gen.containerOf[ArrayList, Song](songs)" a generator for ArrayLists of Song objects is created! That generator is used in the "testSongsList must pass" function in the body of which the behavior of the service is tested: it is initialized with the generated ArrayList and it is checked if the first item of the list is the EVERY_ARTIST item.

When that test is executed it doesn't only run once like normal tests, no, it actually runs a hundred times out of the box, testing the service method with a different array list each time, thanks to the ScalaCheck generator! Of course, it is possible to customize each execution, set the number of times each test is run. In case you don't trust ScalaCheck you can even check which data it has generated!

Conclusio: Specs is great for precise, behavioral tests, ScalaCheck is great because of its generator facilities and Scala is great anyway! Since Scala is fully compatible to Java (and vice versa) you can start testing in Scala now while trusting good old Java code in production code. Imho it's better to switch to Scala anyway but it's up to you...

UPDATE: The example project can be checked out by "git clone git://specsscalacheck.git.sourceforge.net/gitroot/specsscalacheck/specsscalacheck". It is a SBT (Simple Build Tool) Project, so you need to download the SBT jar and execute "sbt test" to run the tests...

[qoholiccom]

Java Scala developer

Job Title: Java Scala Developer Location: Bentonville, AR Duration: Longterm Job Description: Excellent problem-solving, communication and analytical skills 5 + years of experience in Strong grasp of functional programming constructs and approaches, with a focus on Scala. 2+ years of Experience with Scala 2.10 or higher, SBT, ScalaTest, ScalaCheck The Light bend Stack: Akka, Play, Slick, Akka Streams Fluency with SQL and/or NoSQL databases: Postgres, Riak, Cassandra, HBase, MongoDB, etc. Reactive programming and principles Apache Spark, Hadoop, Steam Processing Kafka, RabbitMQ, Spring Integration/Batch, Camel Web Technologies: JavaScript, Angular, jQuery, React, HTML5, CSS3 Must have Micro-services Development experience Reference : Java Scala developer jobs source http://www.qoholic.com/index.php?page=item&id=2361

[jobsaggregationco]

Java Scala Developer

Job Title  :   Java Scala Developer Location  :  Bentonville, AR Duration  :  Long Term Contract Primary Skills : We have an Urgent need to find a Scala Developer (please do not submit anyone with a Hadoop background). Client would prefer for someone that has 8 years of Java developing experience. This candidate must have:  Scala, micro-services development and Spark. Here are the rest of the skills that he is looking for Job Description:     Excellent problem-solving, communication and analytical skills     5 + years of experience in Strong grasp of functional programming constructs and approaches, with a focus on Scala.     2+ years of Experience with Scala 2.10 or higher, SBT, ScalaTest, ScalaCheck     The Light bend Stack: Akka, Play, Slick, Akka Streams     Fluency with SQL and/or NoSQL databases: Postgres, Riak, Cassandra, HBase, MongoDB, etc.     Reactive programming and principles     Apache Spark, Hadoop, Steam Processing     Kafka, RabbitMQ, Spring Integration/Batch, Camel     Web Technologies: JavaScript, Angular, jQuery, React, HTML5, CSS3     Must have Micro-services Development experience -- Reference : Java Scala Developer jobs source http://jobsaggregation.com/jobs/technology/java-scala-developer_i1894

[jobrealtimeco]

Java Scala developer

Job Title: Java Scala Developer Location: Bentonville, AR Duration: Longterm Job Description: Excellent problem-solving, communication and analytical skills 5 + years of experience in Strong grasp of functional programming constructs and approaches, with a focus on Scala. 2+ years of Experience with Scala 2.10 or higher, SBT, ScalaTest, ScalaCheck The Light bend Stack: Akka, Play, Slick, Akka Streams Fluency with SQL and/or NoSQL databases: Postgres, Riak, Cassandra, HBase, MongoDB, etc. Reactive programming and principles Apache Spark, Hadoop, Steam Processing Kafka, RabbitMQ, Spring Integration/Batch, Camel Web Technologies: JavaScript, Angular, jQuery, React, HTML5, CSS3 Must have Micro-services Development experience Reference : Java Scala developer jobs source http://jobrealtime.com/jobs/technology/java-scala-developer_i2061