jscodeshift-ava-tester

jscodeshift wrapper to write smaller and better tests for your codemods using AVA

Install

$ npm install --save jscodeshift-ava-tester

Usage

Let's say you want to write tests for a jscodeshift codemod in <root>/lib/codemod-to-test.js. You can create a test file <root>/test/codemod-to-test.js and write plenty of small tests to test your codemod as thoroughly as you want.

import test from 'ava';
import jscodeshift from 'jscodeshift';
import testCodemod from 'jscodeshift-ava-tester';
import codemod from '../lib/codemod-to-test';

const {testChanged, testUnchanged} = testCodemod(jscodeshift, test, codemod);

// Let's assume `codemod` modifies `var` declarations to either `let` or `const`

// Test things that should be modified
testChanged('var foo = 2;', 'const foo = 2;');
testChanged('var foo;', 'let foo;');
testChanged('var foo = 2; foo = 3;', 'let foo = 2; foo = 3;');
testChanged('var foo = 2; foo++;', 'let foo = 2; foo++;');
testChanged('var foo = 2; foo++;', 'let foo = 2; foo++;');
// ...

// Test things that should stay as is
testUnchanged('const foo = 2;');
testUnchanged('let foo = 2;');
testUnchanged('let foo;');
// ...

You can then run AVA as you would for other AVA tests (using ava or maybe even ava --watch).

API

testCodemod(jscodeshift, test, codemod)

Return methods that run the codemod on the given input and assert whether modifications are made, using the jscodeshift and AVA modules that you provide.

jscodeshift

The jscodeshift module that you use in your project.

test

The AVA module that you use in your project.

codemod

The codemod to test.

Returns

An object containing two methods: testChanged and testUnchanged.

testChanged([title], input, expectedOutput)

Create a test that ensures that the codemod modifies input to expectedOutput.

title

Optional title for the test. If omitted, input will be used as the title.

input

Mock content of an input file.

expectedOutput

Expected result of the codemod when given input.

testUnchanged([title], input)

Create a test that ensures that the codemod does not modify input.

title

Optional title for the test. If omitted, input will be used as the title.

input

Mock content of an input file.

Thanks

Special thanks to @jamestalmage who created the original script.

License

MIT © Jeroen Engels