iox-#5 Add RouDiEnvironment for testing

[elBoberido]

Pre-Review Checklist for the PR Author

1. Code follows the Rust coding style and is formatted with rustfmt
2. Branch follows the naming format (iox-#123-this-is-a-branch)
3. Commits messages are according to this guideline
   • Commit messages have the issue ID (iox-#42 commit text)
   • Commit author matches Eclipse Contributor Agreement (and ECA is signed)
4. Update the PR title
   • Follow the same conventions as for commit messages
   • Link to the relevant issue
5. Relevant issues are linked
6. Add sensible notes for the reviewer
7. All checks have passed (except task-list-completed)
8. Assign PR to reviewer

Notes for Reviewer

This PR adds a testing module with the RouDiEnvironment and a simple test which uses the RouDiEnvironment.

Further test will be added with a future PR since #23 will refactor the API.

Checklist for the PR Reviewer

• Commits are properly organized and messages are according to the guideline
• Code according to our coding style and naming conventions
• PR title describes the changes

Post-review Checklist for the PR Author

1. All open points are addressed and tracked via issues

References

• Relates to Create integration tests #5

[dkroenke]

Testcases are missing, additionally the code needs to be formatted with rustfmt

[elfenpiff]

I love this API.

[elBoberido]

Hehe, unfortunately the subscribe/offer on create feature broke this. One could think of something like

let topic = TopicBuilder::<CounterTopic>::new("Test", "BasicPubSub", "Counter").build()?;
let (subscriber, sample_receive_token) = topic.subscriber().history_request(1).create();
let publisher = topic.publisher().history_capacity(5).create();

[elBoberido]

... oh, and ideally it would be TopicBuilder::<CounterTopic>::new("/Test/BasicPubSub/Counter").build()?; ... maybe for the 0.2 release :)