dont-break

Checks if the node module in the current folder breaks unit tests for specified dependent projects.

Relevant discussion at npm, Do not break dependant modules.

Install

npm install -g dont-break

Use

• Create .dont-break.json file in the root of your package, list module names that you would like to test as an array.
• Run dont-break any time to test latest version of each dependent module against the curent code

Example

2 projects.

1. First project foo only exports single variable module.exports = 'foo';
2. Second project foo-user depends on foo.

foo-user only works if it gets string foo from the module it depends on, like this:

var str = require('foo');
console.assert(str === 'foo', 'value of foo should be "foo", but is ' + str);

foo has only a single release 0.1.0 that works for foo-user project.

The author of foo changes code to be module.exports = 'bar'; and releases it as 0.2.0. foo-user wants to use the latest foo so it updates its dependency, not expecting anything bad - foo's minor version number has been upgraded. In semantic versioning it means no breaking API changes.

foo-user is now broken!

Instead, before publishing new version to NPM, project foo can create a file in its project folder .dont-break.json with names of dependent projects to test

echo '["foo-user"]' > .dont-break.json

You can check if the current code breaks listed dependent project by running

dont-break

This will install each dependent project from .dont-break.json file into /tmp/dont-break... folder, will run the dependent's unit tests using npm test to make sure they work initially, then will copy the current project into the temp folder, overwriting the previous working version. Then it will run the tests again, throwing an exception if they stopped working.

In the example case, it will report something like this

$ dont-break
dependents [ 'foo-user' ]
testing foo-user
  installing foo-user
installed into /tmp/[email protected]
  npm test
tests work in /tmp/[email protected]/lib/node_modules/foo-user
copied /Users/gleb/git/foo/* to /tmp/[email protected]/lib/node_modules/foo-user/node_modules/foo
  npm test
npm test returned 1
test errors:
AssertionError: value of foo should be "foo", but is bar
npm ERR! Test failed.  See above for more details.
npm ERR! not ok code 0
tests did not work in /tmp/[email protected]/lib/node_modules/foo-user
code 1
FAIL: Current version break dependents

The message clearly tells you that the dependent projects as they are right now cannot upgrade to the version you are about to release.

Dependencies

You can specify GitHub repos as dependencies, because they most likely will have tests. For example in .dont-break.json

// you can use JavaScript comments in this file .dont-break.json
[
  "https://github.com/bahmutov/dont-break-bar"
]

Picking projects to test manually is a judgement call. Dont-break can fetch top N most downloaded or most starred dependent modules and save the list.

• run dont-break --top-downloads <N> to find top N most downloaded dependent modules, save to .dont-break.json and check.
• run dont-break --top-starred <N> to find top N most starred dependent modules, save to .dont-break.json and check.

The above commands overwrite .dont-break.json file.

Configuration options

Global vs. project-level configuration

You can specify different configuration options on global level or on project level. Following configs are equivalent. Project level:

[
  {
    "name": "project-a",
    "test": "grunt test"
  },
  {
    "name": "project-b",
    "test": "grunt test"
  },
  {
    "name": "project-c",
    "test": "npm test:special"
  }
]

Global level:

{
  "test": "grunt test",
  "projects": [
    "project-a", 
    "project-b", 
    {
      "name": "project-c",
      "test": "npm test:special"
    }
  ]
}

Global level will simplify dont-break config if dependent projects share the same options. Also, options can be overriden on project level as in case of "project-c" here.

Execution flow overview

Dont-break performs folowing steps for each dependent project:

• Clone the dependent project repo into temporary dir using git clone, if dependent project is a Github repo url
• Install the dependent project in temporary dir using the specified command
• Run post-install command if pre-test is not disabled
• Pre-test the dependent project if this is not disabled
• Install current module into the dependent project
• Run post-install command
• Test the dependent project

Sections below describe how you can customize these steps.

Test command

You can specify a custom test command per dependent module. For example, to run grunt test for foo-module-name, but default command for module bar-name, list in .dont-break.json the following:

[
  {
    "name": "foo-module-name",
    "test": "grunt test"
  },
  "bar-name"
]

Install command

You can specify a custom install command per dependent module. By default it's npm install. For example, this will use yarn add for foo-module-name, but keep default npm install for module bar-name:

[
  {
    "name": "foo-module-name",
    "install": "yarn add"
  },
  "bar-name"
]

The name of dependent module will be added to given command, e.g. for above it will run yarn add foo-module-name.

Post-install command

Before testing the dependent package dont-break installs its dev dependencies via npm install command run from the dependency directory. If you need something more you can specify it via "postinstall" config parameter like this:

[
  {
    "name": "packageA",
    "postinstall": "npm run update"
  }, {
    "name": "packageB"
  }
]

If specified this command will run first before pretesting the old version of lib (if pretest isn't disabled), then after installing current version of lib to dependent package. You can use $CURRENT_MODULE_DIR variable here which will be replaced with a path to current module:

[
  {
    "name": "packageA",
    "postinstall": "$CURRENT_MODULE_DIR/install-all-deps.sh",
  }
]

Pre-testing with previous package version

By default dont-break first tests dependent module with its published version of current module, to make sure that it was working before the update. If this sounds excessive to you you can disable it with {"pretest": false} option:

[
  {
    "name": "foo-module-name",
    "test": "grunt test",
    "pretest": false
  }
]

Here "foo-module-name" module will be tested only once, and "bar-name" twise: first with its published version of current module, and then with the updated version.

The "pretest" property can also accept custom script to run for pretesting:

[
  {
    "name": "foo-module-name",
    "test": "grunt test",
    "pretest": "grunt test && ./ci/after-pretesting-by-dont-break"
  }
]

By default it equals to "test" command.

Current module installation method

To test dependent package dont-break installs current module inside the dependent package directory. By default it uses npm install $CURRENT_MODULE_DIR. You can enter your command there, e.g. yarn add $CURRENT_MODULE_DIR. There are also pre-configured options npm-link and yarn-link. They can be helpful in some cases, e.g. if you need to use npm install or yarn in postinstall command. To use npm link method specify {"currentModuleInstall": "npm-link"}:

{
  "currentModuleInstall": "npm-link",
  "projects": ["packageA", "packageB"]
}

Env vars exported to called scripts

Following env vars are available for use in scripts called by executed steps:

• $CURRENT_MODULE_DIR - directory of current module
• $CURRENT_MODULE_NAME - name of current module as stated in its package.json

Installation timeout

You can specify a longer installation time out, in seconds, using CLI option

dont-break --timeout 30

Related

dont-break is the opposite of next-update that one can use to safely upgrade dependencies.

Setting up second CI for dont-break

I prefer to use a separate CI service specifically to test the current code against the dependent projects using dont-break. For example, the project boggle is setup this way. The unit tests are run on TravisCI using pretty standard .travis.yml file

language: node_js
node_js:
  - "0.12"
  - "4"
branches:
  only:
    - master
before_script:
  - npm install -g grunt-cli

Then I setup a separate build service on CircleCi just to run the npm run dont-break command from the package.json

"scripts": {
    "dont-break": "dont-break --timeout 30"
}

We are assuming a global installation of dont-break, and the project lists the projects to check in the .dont-break file. At the present there is only a single dependent project boggle-connect.

To run dont-break on CircleCI, I created the circle.yml file. It should be clear what it does - installs dont-break, and runs the npm script command.

machine:
  node:
    version: "0.12"
dependencies:
  post:
    - npm install -g dont-break
test:
  override:
    - npm run dont-break

To make the status visible, I included the CircleCI badges in the README file.

[![Dont-break][circle-ci-image] ][circle-ci-url]
[circle-ci-image]: https://circleci.com/gh/bahmutov/boggle.svg?style=svg
[circle-ci-url]: https://circleci.com/gh/bahmutov/boggle

which produces the following:

Breaking dependencies? using dont-break

Development and testing

This project is tested end to end using two small projects: boggle and its dependent boggle-connect.

To see open github issues, use command npm run issues

To see verbose log message, run with DEBUG=dont-break ... environment variable.

Small print

Author: Gleb Bahmutov © 2014

• @bahmutov
• glebbahmutov.com
• blog

License: MIT - do anything with the code, but don't blame me if it does not work.

Spread the word: tweet, star on github, etc.

Support: if you find any problems with this module, email / tweet / open issue on Github

Implemented using npm-registry, lazy-ass and npm-utils.

MIT License

Copyright (c) 2014 Gleb Bahmutov

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.