Transform-stream-test NPM

transform-stream-test

Install

npm install transform-stream-test

What

A module that leverages tape to test a transform stream. Transform streams typically take a set of input chunks and deterministically pipes out chunks generated from the input.

transform-stream-test lets you easily create test cases(via tape) where you provide input and assert that you get the output you expect.

Example

var test = require('tape');
var through = require('through');
var tst = require('transform-stream-test');


test('simple test', function(t) {
  var stream = through(),
      fixture = tst(t, stream);

  t.plan(2);

  fixture.deepEqual(
    'foo bar one two three',
    'foo bar one two three',
    'Given a single input chunk the output matched',
    t.ok
  );

  fixture.deepEqual(
    ['foo', 'bar', 'one', 'two', 'three'],
    ['foo', 'bar', 'one', 'two', 'four'],
    'Given multiple input chunks the output chunks did not all match',
    t.error
  );
});

Methods

You create a fixture by calling tst with a tape test object and the transform stream to test.

var fixture = require('transform-stream-test')(t, transformStream);

fixture.deepEqual(input, output, msg, cb, timeout)

Performs a deep equal comparing each output chunk received with each expected output chunk.

input: Array of input chunks
output: Array of expected output chunks
msg: The description of the test case
cb: function fired with cb(success, msg)
- success is a boolean representing whether or not the output matched the expectation
- msg is the same message provided above
timeout: optional number of milliseconds to finish the test case
- This is useful for when you don't expect any output