Where files go

Verified files live in one folder per test project, mirroring the test file's folder, with a folder per test class:

tests/Shop.Tests/
├── Rendering/CatalogTests.cs
└── .snapshots/
    └── Rendering/
        └── CatalogTests/
            ├── Renders.verified.html
            ├── Renders.header.verified.html         {Method}.{name}
            └── RendersPage.a1b2c3d4.verified.html   {Method}.{arguments hash}

• One folder per project, not one next to each test file: source folders hold only source, and a pull request's snapshot changes sit under one prefix.
• By the test file's folder, not its namespace. Moving a test file leaves its snapshots behind; snap orphans finds them.
• A folder per runtime class, so [InheritsTests] classes that share a base class's methods get their own files.
• The arguments hash (eight hex digits) tells data-driven cases apart. It is stable across machines, cultures and versions. A fixture injected with TUnit's [ClassDataSource<T>], through the constructor or a method parameter, is not test data and stays out of the hash, so a class with a fixture gets plain {Method} names. Line endings in a string argument are read as \n, so a multi-line string from a source file hashes the same on a Windows checkout (CRLF) as on Linux and macOS.

A snapshot can also belong to a file rather than a test. Snapshot.MatchFile keys it by the file's path in the project, without the extension, so every runner of that file shares one verified file:

tests/Shop.Tests/
├── journeys/checkout.journey
└── .snapshots/
    └── journeys/
        └── checkout.verified.journey             Shop.Tests/journeys/checkout

Received files never go into the source tree:

.artifacts/.snapshots/received/{Project}/Rendering/CatalogTests/Renders.received.html   with an artifacts path
tests/Shop.Tests/obj/snapshots/received/Rendering/CatalogTests/Renders.received.html     otherwise

Both are ignored in practically every .NET repository already, so a received file cannot be committed by accident.

An inline snapshot has no verified file: its received record is {key}.L{line}.received.inline, and accepting it edits the string literal in the test's source.

Files a file-keyed run writes, such as a journey's screenshots, go into a folder next to its received file, {received}/journeys/checkout.artifacts/, emptied before each run (Snapshot.ArtifactsDirectory).

The library writes only inside these two folders: every write goes through a file system scoped to them.