# Changes in Release 0.4

Major changes in Release 0.4:

* [Unnumbered interface support](../addressing.md#unnumbered-interface-support)
* Link [names](../links.md#link-names) and [roles](../links.md#selecting-custom-address-pools)
* [Configuration modules](../modules.md)
* [OSPF configuration module](../module/ospf.md)

Minor fixes:

* Use custom SSH port in **connect.sh** (**netlab connect** since release 0.8)
* Tags added to **initial-config.ansible** (**netlab initial** since release 0.8)
* Changed default Ansible inventory format
* *Bandwidth* became a [core link attribute](../links.md#link-attributes)

Internal changes (detailed below):

* Using **python-box** instead of Python dictionaries
* Unit tests

## Migrating to python-box

If you ever programmed in any programming language with decent support for hierarchical data structure you might have noticed how crazy navigating through a deep dictionary structure looks like in Python.

Fortunately some people do more than yammer - Chris Griffith created [Box](https://github.com/cdgriffith/Box) to address that, and I found it much easier (and more fluent, and more readable) to use than standard dictionaries.

Unfortunately, Box uses copy-on-use approach which means that you might work on multiple copies of the same dictionary without realizing that (bummer). The only way to make sure nothing is broken was to:

* Create tons of tests
* Get results with the dictionary-only implementation
* Repeat the tests with Box implementation
* Fix stuff until the results match.

I think we're there or the code wouldn't be in **master** branch.

## Tests, tests, tests

The only way to check whether I fixed all instances of intricate differences between dictionaries and Boxes (and there were quite a few of them) was to write tons of tests, including automated CI pipeline implemented with GitHub Actions:

* All tests are in **tests** directory
* Topology transformation tests are YAML files starting with **topology-**. Expected results are in **exp-topology-** YAML files.
* Tests that should result in an error are in **err-** YAML files.

Run tests with **pytest** (parent directory must be in Python include path).

To create code coverage report, run **coverage.sh**.

Please feel free to add further tests to bring code coverage closer to 100%. Thank you.