test-console

test-console

A simple and pragmatic library for testing Node.js console output.

Example

See the API section for more examples.

var stdout = require("test-console").stdout;

var output = stdout.inspectSync(function() {
    console.log("foo");
};
assert.deepEqual(output, [ "foo\n "]);

Installation

This is a Node.js library. Install Node, then:

npm install test-console (add --save or --save-dev if you want)

To use the library in your code, require it as follows:

var stdout = require("test-console").stdout;
var stderr = require("test-console").stderr;

API

• stdout.inspect: Redirects writes to stdout into an array instead of writing them to console.
• stdout.inspectSync: Just like inspect(), but automatically restores the console when done.
• stdout.ignore: Prevent writes to stdout from appearing on the console.
• stdout.ignoreSync: Just like ignore(), but automatically restores the console when done.

The same API is also available on stderr.

inspect = stdout.inspect()

Redirects writes to stdout into an array instead of writing them to the console.

• inspect: Returned as an object with two properties:
  • inspect.output: An array containing one string for each call to stdout.write(). This array updates every time another call to stdout.write() is made.
  • inspect.restore(): Call this function to restore stdout.write to its normal behavior.

Example of using inspect() to test a synchronous function:

var inspect = stdout.inspect();
functionUnderTest();
inspect.restore();
assert.deepEqual(inspect.output, [ "foo\n" ]);

Example of using inspect() to test an asynchronous function:

var inspect = stdout.inspect();
functionUnderTest(function() {
    inspect.restore();
    assert.deepEqual(inspect.output, [ "foo\n" ]);
});

output = stdout.inspectSync(fn)

Just like inspect(), but automatically restores the console when done.

• fn(output): The function to run while inspecting stdout. After the function returns, stdout.write is automatically restored. Note that output is passed into this function in addition to being returned from inspectSync().

• output: Passed into fn and also returned as an array containing one string for each call to stdout.write(). This array updates every time another call to stdout.write() is made.

Example of using inspectSync() to test a synchronous function:

var output = stdout.inspectSync(function() {
    functionUnderTest();
});
assert.deepEqual(output, [ "foo\n" ]);

Example of using `inspectSync() to incrementally test several synchronous functions:

stdout.inspectSync(function(output) {
    functionUnderTest();
    assert.deepEqual(output, [ "foo\n" ]);
    anotherFunctionUnderTest();
    assert.deepEqual(output, [ "foo\n", "bar\n" ]);
});

restore = stdout.ignore()

Prevent writes to stdout from appearing on the console.

• restore(): Call this function to restore stdout.write to its normal behavior.

Example of using ignore() to prevent a synchronous function from writing to the console:

var restore = stdout.ignore();
functionUnderTest();
restore();

Example of using ignore() to prevent an asynchronous function from writing to the console:

var restore = stdout.ignore();
functionUnderTest(function() {
    restore();
});

Example of using ignore() to prevent a suite of tests from writing to the console:

var restoreStdout;

beforeEach(function() {
    restoreStdout = stdout.ignore();
};

afterEach(function() {
    restoreStdout();
};

// tests go here

ignoreSync(fn)

Just like ignore(), but automatically restores the console when done.

• fn(): The function to run while ignoring stdout. After the function returns, stdout.write is automatically restored.

Example of using ignoreSync() to prevent a synchronous function from writing to the console:

stdout.ignore(function() {
    functionUnderTest();
});

Version History

0.7.0: Initial release: inspect(), inspectSync(), ignore(), and ignoreSync()

Contributors

Created by James Shore. Inspired by Brandon Satrom's Automated Testing of Standard Output in Node.js.

License

The MIT License (MIT)

Copyright (c) 2014 James Shore

Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the "Software"), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.