Open-Source Testing · gabrielfalcao

sure

Sure is a Python test automation library and runner that provides a fluent, readable assertion syntax for writing tests. It supports BDD-style test organization and has been maintained since 2010, with active development as of March 2025.

Talk to DEV.co Discuss Implementation

Source: GitHub — github.com/gabrielfalcao/sure

700

GitHub stars

Forks

Python

Primary language

GPL-3.0

License (OSI-approved)

Key facts

Objective fields from the source. Values we can't verify are shown as “Unknown” rather than guessed.

Field	Value
Repository	gabrielfalcao/sure
Owner	gabrielfalcao
Primary language	Python
License	GPL-3.0 — OSI-approved
Stars	700
Forks	74
Open issues	23
Latest release	v2.0.1 (2023-02-06)
Last updated	2025-03-01
Source	https://github.com/gabrielfalcao/sure

What sure is

Sure is a Python testing framework offering a fluent assertion API (e.g., `expects(x).to.equal(y)`) alongside a standalone test runner. It supports both object and string-based assertions, integrates with Python's testing ecosystem, and is distributed via PyPI.

Quickstart

Get the sure source

Clone the repository and explore it locally.

terminalbash

1git clone https://github.com/gabrielfalcao/sure.git2cd sure3# follow the project's README for install & configuration

Need it deployed, integrated, or customized instead? DEV.co ships production installs.

Best use cases

Teams preferring fluent/readable assertion syntax

Sure's chainable assertion API makes test code more natural and maintainable compared to unittest or pytest's assert statements, particularly for teams emphasizing test readability and BDD practices.

BDD-driven projects with Python

The library explicitly supports behavior-driven development patterns and test-driven development workflows, making it suitable for projects organizing tests around user-facing behavior.

Projects with existing Sure test suites

Organizations already using Sure benefit from continued maintenance, active CI/CD integration (GitHub Actions), and evolving assertions library without rewriting tests for another framework.

Implementation considerations

Verify GPL-3.0 license compatibility with your project's licensing model and legal requirements before committing to Sure in production systems.
Sure's fluent syntax is sugar over standard assertions; migration from unittest/pytest assertions requires gradual refactoring or running tests in parallel with both frameworks.
The project has 23 open issues and 2-year gap between v2.0.1 (Feb 2023) and latest push (Mar 2025); assess whether issue resolution velocity meets your needs.
Test discovery and execution depend on the `sure` CLI; verify compatibility with your CI/CD pipelines, Docker environments, and custom test orchestration.
Documentation exists but is not bundled; ensure documentation.readthedocs.io is accessible in your environment and that offline docs are available if needed.

When to avoid it — and what to weigh

GPL-3.0 incompatible licensing constraints — GPL-3.0 is a strong copyleft license. Closed-source or proprietary projects must review legal compatibility before use; linking or distributing Sure requires careful license analysis.
Heavy reliance on pytest ecosystem plugins — Sure is not pytest-native and lacks the ecosystem depth of pytest (fixtures, plugins, parallel execution). Projects dependent on those features should evaluate integration costs.
Need for async/await test support — No documentation provided on native async/coroutine testing support. Projects heavily using asyncio or async frameworks should verify Sure's async capability before adoption.
Requirement for very high test runner performance at scale — Sure's test runner is lightweight but no benchmarks or parallel execution capabilities are documented. Large test suites may benefit more from pytest or nose2.

License & commercial use

Sure uses GPL-3.0 (GNU General Public License v3.0), a strong copyleft license. This means any derivative work or software linked to Sure must also be released under GPL-3.0 or a compatible license. Closed-source or proprietary projects cannot use Sure without legal review and potential compliance obligations.

Commercial use of Sure is legally restricted by GPL-3.0. Organizations using Sure in proprietary products must open-source their entire product or seek alternative licensing. This is a significant barrier for commercial software. Legal review is mandatory; do not assume commercial use is permitted.

DEV.co evaluation signals

Editorial assessment — not user reviews. Directional, with an explicit confidence level.

Signal	Assessment
Maintenance	Moderate
Documentation	Adequate
License clarity	Clear
Deployment complexity	Low
DEV.co fit	Good
Assessment confidence	High

Security considerations

No security vulnerabilities, authentication mechanisms, or data handling are relevant to Sure as a test library. Standard dependency security scanning (pip audit, Dependabot) is recommended to ensure third-party dependencies are up-to-date. Verify that test code using Sure does not inadvertently expose secrets or credentials in output.

Alternatives to consider

pytest

Industry standard, larger ecosystem, pytest plugins, better async support, more active development. Permissive MIT license (no copyleft). Recommended for new projects unless fluent assertion syntax is critical.

unittest (Python stdlib)

No external dependencies, standard library, built-in assertion methods. Verbose but zero licensing risk. Best for organizations avoiding external test frameworks.

nose2

Lightweight test runner with plugin architecture, BSD license (permissive). Less popular than pytest but avoids GPL copyleft constraints.

Software development agency

Build on sure with DEV.co software developers

Sure offers readable, fluent assertions and a lightweight test runner for Python projects. If you're using it or considering it, verify GPL-3.0 license compatibility first. Contact us for guidance on test framework selection and integration strategy.

Talk to DEV.co

Related open-source tools

Surfaced by semantic similarity across the DEV.co open-source index.

truth Verify robotframework

Related on DEV.co

Explore the category and the services that help you build with it.

Open-Source Testing Application Development DevOps & Testing Infrastructure Talk to DEV.co

sure FAQ

Can we use Sure in a proprietary/closed-source project?

Not without legal review and potential license change. GPL-3.0 requires derivative works to be open-source. Consult legal counsel before adopting Sure for proprietary software.

Does Sure work with pytest?

Sure is not pytest-native. It can coexist in the same project but runs via its own test runner (`sure tests`). Mixing Sure and pytest tests requires dual execution or custom tooling.

Is Sure actively maintained?

Moderately. Last push was March 2025 and CI/CD is active, but the latest release was February 2023 (v2.0.1) with 23 open issues. Monitor the repository for stagnation, but current status is not abandoned.

What Python versions does Sure support?

PyPI badges in README indicate multi-version Python support, but specific version numbers are not provided in the data. Check PyPI page or setup.py for exact compatibility matrix.

Software developers & web developers for hire

DEV.co helps companies turn open-source tools like sure into production software. Our software development services cover the full lifecycle — architecture, web development, integration, and maintenance — delivered by software developers and web developers who ship. Engage our software development agency to implement or customize it for your open-source testing stack.

Evaluate Sure for your Python testing needs

Talk to DEV.co Schedule a Consultation