dont-break | current version of your package would break | Build Tool library

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:. The name of dependent module will be added to given command, e.g. for above it will run yarn add foo-module-name.
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"}:.
You can specify a longer installation time out, in seconds, using CLI option.
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. Then I setup a separate build service on CircleCi just to run the npm run dont-break command from the package.json. 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. To make the status visible, I included the CircleCI badges in the README file.