Question 1

Should I use StreamData or PropCheck for property-based testing in Elixir?

Accepted Answer

StreamData is best for idiomatic Elixir integration and data generation, while PropCheck is better for stateful testing and counter-example storage. The README highlights these differences to help choose based on project needs like advanced modeling.

Question 2

How do I create a custom generator for email addresses in StreamData?

Accepted Answer

Use the ExUnitProperties.gen macro with StreamData generators; for example, combine string(:alphanumeric) and member_of(domains) as shown in the README's email example. This allows flexible creation of domain-specific data types with constraints.

Question 3

Is StreamData good for beginners in property-based testing?

Accepted Answer

StreamData has a gentle learning curve with its Elixir-native API, but property-based testing itself requires understanding of concepts; it's approachable but still demands familiarity with testing principles and generator design.

Question 4

How can I reproduce a failing property test in StreamData?

Accepted Answer

StreamData uses seeds for randomness; to reproduce a failure, you need to reuse the seed that caused it, as the library doesn't automatically store counter-examples in files. This requires careful seed management during test runs.

Question 5

Can StreamData be used outside of tests for data generation?

Accepted Answer

Yes, StreamData generators implement the Enumerable protocol and can be used in any Elixir context to produce infinite streams of random data, not just in tests. They integrate seamlessly with Elixir's core libraries for various applications.

Question 6

What are common pitfalls when writing properties with StreamData?

Accepted Answer

Common mistakes include not properly constraining generator data, leading to irrelevant test cases, or overlooking edge cases that property-based testing aims to catch. It's crucial to design properties that accurately reflect code behavior.

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