Symmetric Properties
Explore symmetric properties in property-based testing, which validate reversible operations by checking if applying opposite actions returns the initial input. This lesson helps you understand how to write concise properties that test interconnected components like encoders and decoders together, improving test coverage with minimal effort. You will also learn the role of invariants and how symmetric properties complement traditional tests to ensure system reliability.
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What are symmetric properties?
From time to time, we may find it difficult to discern what components depend on each other to succeed. Two bits of code may perform opposite actions, such as an encoder and a decoder. We need the encoder to test the decoder, and the decoder to test the encoder. In other cases, we may have a chain of operations that could be made reversible:
- Editing text and undoing changes,
- Translating text from French to English to Spanish and back to French.
- Passing a message across multiple servers until it’s back to its original one.
- Allowing a character in a game to walk in every direction until it makes its way back to its origin.