# TestableIO/System.IO.Abstractions

Just like System.Web.Abstractions, but for System.IO. Yay for testable IO access!

Repository: https://github.com/TestableIO/System.IO.Abstractions
Canonical: https://ross.abutalabs.com/products/systemioabstractions
Homepage: http://www.nuget.org/packages/System.IO.Abstractions
Language: C#
License: MIT
License Family: permissive
Topics: testing, mocks, dotnet, c-sharp, filesystem, io, cross-platform, tdd
Last push: 2026-08-25T15:15:55+00:00

## Health v2 (maintenance only)
Score: 97/100 (v2, computed 2026-09-02T17:46:02.011165+00:00)
- activity 99, release rhythm 92, longevity 100
- inputs: {"age_days": 5264, "days_push": 8, "days_rel": 52, "gap_med": 22.0, "n_releases_24m": 19}
- flags: none
- formula: round(0.45*activity + 0.35*rhythm + 0.20*longevity); archived -> min(score, 10)

## Adoption (not part of the score)
Stars 1627, forks 261 (observed 2026-08-28T04:05:13.215506+00:00)

## What it is
A .NET library providing an injectable abstraction (IFileSystem) over System.IO so file access code can be tested. It mirrors the System.IO API and ships test helpers like a mock file system.

## Use cases
- unit test code that reads and writes files
- inject a mock file system into .NET components
- avoid touching the real disk in tests
- abstract System.IO calls behind an interface
- test file and directory logic with TDD

## When to choose
- you write C#/.NET code that does file IO and want it testable
- you want a drop-in API-compatible wrapper around System.IO
- you need in-memory mock file system helpers for tests

## When to avoid
- your code has no file system interaction
- you need a fully faithful emulation of real file system behavior
- you are not on .NET

## Facets
- artifact type: library
- maturity: active
- function: testing, mocking, file-system
- domain: testing, developer-tools, files
- platform: dotnet, cross-platform
- tags: tdd, dependency-injection, c-sharp, unit-testing, filesystem-abstraction

## Member repositories
- TestableIO/System.IO.Abstractions (main) score 97

## Provenance
- Observed fields: from GitHub, fetched 2026-08-28T04:05:13.215506+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 2026-08-30T03:48:23.067525+00:00, confidence not recorded.
  - readme: https://github.com/TestableIO/System.IO.Abstractions (fetched 2026-08-28T04:05:13.215506+00:00, sha c55489301ed1)
  - homepage: http://www.nuget.org/packages/System.IO.Abstractions (fetched 2026-08-29T11:20:59.754715+00:00, sha da09e946134d)
  - site_page: https://www.nuget.org/policies/About (fetched 2026-08-29T11:20:59.757858+00:00, sha a113b8a074c9)
- Data as of 2026-08-30T08:39:29.467469+00:00.