Side by side
Hypothesis vs PropEr
Both stand on property-based testing tools. Which one you can start free with, which one lets you read the code, and what each costs once you pay.
Free plan LinuxMacWindows
Hypothesis adds generated-input property testing to an existing Python test framework, with failure reduction and replay. Users should account for its version policy and the need for a separate test runner.
Visit Hypothesis Free plan Self-hosted
PropEr offers property-based and model-based random testing for Erlang, with integration options for common Erlang test runners. Its generator and type languages differ for list expressions, and filtering can require repeated attempts.
Visit PropErThe facts
| Hypothesis | PropEr | |
|---|---|---|
| Free plan | Yes | Yes |
| Open source | Not published | Not published |
| Runs on | Linux, Mac, Windows | Self-hosted |
| Lowest paid plan | Not published | Free or on request |
| Plans published | None | 1 |
| Maker | Not published | Not published |
| Website | hypothesis.works | proper-testing.github.io |
| On property-based testing tools | #7 of 28 | #11 of 28 |
Hypothesis: what it does well
- Generates inputs including edge cases
- Simplifies failing examples
- Stores failures for replay
- Supports pytest and unittest
- Can generate stateful operation sequences
What to know first
- Not a test runner itself
- Supports only the most recent version
- Undocumented behavior may change in patch releases
PropEr: what it does well
- Generates data from Erlang type declarations
- Can test functions using Erlang specifications
- Supports EUnit and Common Test
- Includes failing-case shrinking
What to know first
- Designed for Erlang programs
- Filtering may keep trying values until one passes
- Requires a self-hosted installation
Alternatives to Hypothesis Alternatives to PropEr The whole list