Testing on the Pyret track

Installing Prerequisites

After you successfully download an exercise, you will need to install the Node.js modules to run the tests:

cd /path/to/exercise
npm install

Then add the directory containing the pyret command line tool to your $PATH

# bash
PATH="./node_modules/.bin:$PATH"

# zsh
path=(./node_modules/.bin $path)

# fish
fish_add_path ./node_modules/.bin

Getting Started

There will be several files inside the exercise directory, but the most two important are your solution and test files. In the following example, we've downloaded the Leap exercise.

leap/
├── leap.arr       # Solution file - your code goes here
├── leap-test.arr  # Test cases for the exercise

To run the tests, either use exercism test if you've downloaded the official Exercism CLI or run pyret leap-test.arr. Pyret will run the test suite which consists of a series of labeled check blocks that test your solution file against specific inputs and expected results. A critical part of this process is explicitly exporting portions of your code so the test suite can see it.

provide

Tests on this track will import your file, allowing access to anything explicitly exported from your code.

To export variables, you need to add a provide statement at the beginning of your file.

The following snippets are two valid ways to export a, b, and c.

# using a list of bindings
provide a, b, c end

# using an object literal
provide {
  a: a,
  b: b,
  c: c
}
end

A third method, provide *, is a shorthand for exporting all the top-level bindings except for custom data types However, it's generally not recommended because Pyret is strict about not allowing shadowing.

provide-types

Some exercises will require a custom data type to be exported for testing purposes. In those situations, you can use a provide-types statement. Since a data type has additional functions that might not be exported, it's advised to use provide-types * despite the shadowing concern.

provide-types *

data MyPoint:
  | two-dim(x, y)
  | three-dim(x, y, z)
end

All exercise stubs will have either provide or provide-types statements set up for your use.