What is reactor??
Image Source: Fusion Reactor from MIT: http://www.computerworld.com/article/3028113/sustainable-it/mit-takes-a-page-from-tony-stark-edges-closer-to-an-arc-fusion-reactor.html
In simple words: Reactor is what makes multi-module builds possible
It determines the correct build order from the dependencies stated by each project in their respective project descriptors, and will then execute a stated set of goals.
It computes the directed graph of dependencies between modules, derives the build order from this graph and then executes goals on the modules. In other words, a "multi-modules build" is a "reactor build" and a "reactor build" is a "multi-modules build" :)
Reactor does this:
- Collects all the available modules to build
- Sorts the projects into the correct build order
- Builds the selected projects in order
How this fits in the test automation space?
- Test Data Seeding
- Test Execution
- Reporting Framework
- Test Coverage
Here is a good example: https://thomassundberg.wordpress.com/2012/02/18/test-coverage-in-a-multi-module-maven-project/
What you should read: