# assertj/assertj

Fluent testing assertions for Java and the JVM

Repository: https://github.com/assertj/assertj
Canonical: https://ross.abutalabs.com/products/assertj
Homepage: https://assertj.github.io/doc/
Language: Java
License: Apache-2.0
License Family: permissive
Topics: java, typed-assertions, testing, assertions, assertj, hacktoberfest, kotlin, groovy
Last push: 2026-08-26T22:09:18+00:00

## Health v2 (maintenance only)
Score: 88/100 (v2, computed 2026-09-03T02:20:16.233290+00:00)
- activity 99, release rhythm 67, longevity 100
- inputs: {"age_days": 4920, "days_push": 7, "days_rel": 221, "gap_med": 14, "n_releases_24m": 8}
- flags: none
- formula: round(0.45*activity + 0.35*rhythm + 0.20*longevity); archived -> min(score, 10)

## Adoption (not part of the score)
Stars 2842, forks 787 (observed 2026-08-28T04:07:24.811977+00:00)

## What it is
AssertJ is a Java library providing a rich set of strongly-typed, fluent assertions for unit testing with JUnit, TestNG, or any other test framework. It includes modules for JDK types, Guava, Joda Time, Neo4j, databases, and Swing UI testing.

## Use cases
- write readable unit test assertions in Java
- replace JUnit assertions with fluent typed assertions
- assert collections, maps, and streams in tests
- test relational database contents
- functional testing of Swing UIs
- get helpful error messages from failed assertions

## When to choose
- you write Java/JVM unit tests and want type-specific, discoverable assertions
- you want better failure messages than JUnit's built-in asserts
- you need assertions for Guava, Joda Time, Neo4j, or database types

## When to avoid
- you are not on the JVM
- your team is standardized on plain JUnit assertions or Hamcrest and has no need to migrate

## Facets
- artifact type: library
- maturity: stable
- function: testing
- domain: testing, developer-tools
- platform: jvm, jvm-scripting
- tags: assertions, fluent-api, unit-testing, tdd, junit, testng, jvm

## Member repositories
- assertj/assertj (main) score 88

## Provenance
- Observed fields: from GitHub, fetched 2026-08-28T04:07:24.811977+00:00.
- Health v2: computed from the inputs above; adoption is never an input.
- Inferred fields (summary, facets, guidance): AI-extracted, prompt v1, taxonomy v1, on 2026-08-30T07:37:13.728163+00:00, confidence not recorded.
  - readme: https://github.com/assertj/assertj (fetched 2026-08-28T04:07:24.811977+00:00, sha 2f3add0d5bc1)
  - homepage: https://assertj.github.io/doc/ (fetched 2026-08-29T09:52:44.730684+00:00, sha fe1624edf7f8)
- Data as of 2026-08-30T08:39:29.467469+00:00.