Shuffle

An application that produces a shuffled set of values.

Status

Travis CI Build Status:

Codecov.io Code Coverage Status:

Introduction

Shuffle takes a single positive integer as input (N) and produces a list of integers in the range 1..N shuffled in a random order.

It uses the Fisher-Yates Shuffle to produce the list as fast a reasonably possible regardless of size.

For speed and memory reasons, it has a limitation of only producing lists with up to 10 million items.

Building Shuffle

In order to build Shuffle, you need to have Java 8 SE Developer Kit installed on your system.

After pulling the Git repo, you can build the application by calling:

./gradlew installDist

Shuffle is built with Gradle wrapper, which will:

download an embedded version of the Gradle build tools
download all required dependencies
build the application jar
download wrapper scripts that make executing Shuffle easier

Running Shuffle

The Shuffle application binaries are installed in the build/install/Shuffle directory. In order to run the application, navigate to the directory and run:

bin/Shuffle -n <numValues>

where numValues is the number of values that will be shuffled.

If you run into problems, you can run:

bin/Shuffle -h

To get a full list of options.

Testing Shuffle

Shuffle has a full suite of unit tests. The tests are designed to ensure that the application will perform as expected given valid input and also ensures that the lists produced are a sufficiently randomized set of values.

In order to run the unit tests included in Shuffle, use Gradle's check target:

./gradlew check

The test results can be viewed by opening build/reports/tests/index.html

Under the shuffle package, there are 2 groups of tests:

ShuffleApplicationTest tests ensure that Shuffle accepts and processes valid input.
ShufflerTest ensures that the output produced by Shuffle is correct and suitably shuffled.