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Refactoring Phoenix Contact's Graphical Editor: Embracing Testability & Extensibility

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Project Overview

At Phoenix Contact, I was entrusted with refining an existing graphical editor. My colleague had initiated the development, and an MVP was in place. My journey began by acquainting myself with the editor and recognizing potential avenues for improvement, especially in terms of testability.

The Challenges

While the foundation of the editor was robust, its architecture didn’t support testability. Object creation was intertwined with dependency management, making it a challenge to implement efficient unit tests.

My Role & Approach

Implementing Inversion of Control (IoC)

To address the testability challenge, my primary objective was to restructure the application by introducing IoC. This design pattern ensured that objects received their dependencies from outside rather than creating them internally, a change pivotal in enabling unit testing.

Testing Framework Development

Post-restructuring, I developed a comprehensive testing framework. This involved both traditional unit tests and Behavior-Driven Development (BDD) style tests using SpecFlow. This layered testing approach ensured thorough coverage and efficacy.

Additional Responsibilities

As I delved deeper into the project:

  • Feature Expansion: I continually added new functionalities to the editor, like crafting routing algorithms.
  • SFC Editor Creation: Drawing from the primary editor, I spearheaded the development of a new editor tailored for Sequential Function Chart (SFC). The central challenge here was devising an automatic arrangement algorithm.

Outcomes & Legacy

The refactored editor base, enhanced for testability and extensibility, became a cornerstone within our framework. Various editors within the ecosystem have since been built upon this foundational architecture.

Reflections & Lessons Learned

This project offered profound insights. Most notably, I discerned that unit tests might not always be the optimal choice, especially when the inner architecture is in flux. Integration tests, particularly with tools like SpecFlow, provide unparalleled reliability in such scenarios. Today, my testing strategy revolves around unit tests for high-permutation classes, like algorithms, while leaning on integration tests for broader functionalities.

Future Directions

While I’ve transitioned from the project, further refinements have been made post my tenure. These enhancements focused on eliminating architectural inefficiencies and bolstering code readability.


This project at Phoenix Contact was a testament to the importance of adaptability in software engineering. While established systems offer a foundation, continual introspection and restructuring pave the way for optimization, ensuring the software’s longevity and efficacy.

Engage & Collaborate! 🚀

Have thoughts, insights, or experiences related to this project? I'd love to hear from you. Reach out via the contact form and let's connect!


  • C#
  • XAML
  • SpecFlow
  • MEF
Time Investment: 4 years