Prefire transforms your #Preview blocks into:

• ✅ Snapshot tests
• ✅ Playbook views
• ✅ Visual flows with states and user stories
• ✅ Living documentation — fully automated

• 🧠 Smart Preview Parsing — including #Preview, @Previewable
• 📸 Snapshot Testing — automatic test generation from previews
• 📚 Playbook View — auto-generated interactive component catalog
• 🏃 Flow-aware — build user stories from multiple preview steps
• 🧩 UIKit Support — support for UIView and UIViewController
• ⚙️ SPM + Xcode Plugins — works in CLI, Xcode build phases, or CI
• 🧠 Fast Caching — fingerprint-based AST and body caching avoids redundant work
• ✍️ Stencil Templates — customize output with your own templates

• 🔥 Save Time - Generate tests and documentation automatically
• 🔥 Stay Consistent - Keep previews and tests always in sync
• 🔥 Improve Quality - Catch visual regressions before users do
• 🔥 Boost Collaboration - Share living documentation with your team

📦 Example project available at: Prefire Example

// Package.swift dependencies: [ .package(url: "https://github.com/BarredEwe/Prefire.git", from: "4.0.0") ], .testTarget( plugins: [ // For Snapshot Tests .plugin(name: "PrefireTestsPlugin", package: "Prefire") ] )

#Preview { Button("Submit") }

Just run the test target 🚀 — Prefire will auto-generate snapshots based on your previews.

💡 If your test target is empty, Prefire will still generate files and snapshot code during build.

Supports:

• ✅ SPM Plugin (Package.swift)
• ✅ Xcode Build Tool Plugin
• ✅ CLI (brew install prefire)
• ✅ GitHub Actions / CI

See detailed setup in the Installation guide

• Finds all #Preview and PreviewProvider blocks
• Supports modifiers: .prefireEnabled(), .prefireIgnored()

• Based on file modification date + SHA-256 of inputs
• Avoids re-parsing if nothing changed

• Uses Stencil templates
• Respects .prefire.yml configuration

• Groups by UserStory, State
• Outputs PreviewModels.generated.swift

To generate tests and playbook, simply mark your preview using the PrefireProvider protocol:

struct Text_Previews: PreviewProvider, PrefireProvider { static var previews: some View { ... } }

If you use the #Preview macro, 🔥Prefire will automatically find it!

If you don't need it, mark view - .prefireIgnored():

#Preview { Text("") .prefireIgnored() }

If you want to disable the automatic get of all previews, use the setting preview_default_enabled: false. Then to include preview in the test, you need to call the .prefireEnabled():

#Preview { Text("") .prefireEnabled() }

To use Playbook, simply use PlaybookView

• If you want to see a list of all the Views, use isComponent: true
• If you want to sort by UserStory, use isComponent: false

import Prefire struct ContentView: View { var body: some View { PlaybookView(isComponent: true, previewModels: PreviewModels.models) } }

Just run generated tests 🚀 All tests will be generated in the DerivedData folder.

Plugin PrefireTestsPlugin will handle everything for you 🛠️

For detailed instruction, check out swift-snapshot-testing or examine an example project.

Prefire provide new commands for previews:

• You can set the delay, precision and perceptualPrecision parameters for the snapshot:

  .snapshot(delay: 0.3, precision: 0.95, perceptualPrecision: 0.98)

  static var previews: some View { TestView() .snapshot(delay: 0.3, precision: 0.95, perceptualPrecision: 0.98) }

• Function for connecting preview together in one Flow:

  

  .previewUserStory(.auth)

  static var previews: some View { PrefireView() .previewUserStory(.auth) } static var previews: some View { AuthView() .previewUserStory(.auth) }

  For example Authorization flow: LoginView, OTPView and PincodeView

  
  

• If a preview contains more than one View, you can mark State for these views.

  

  .previewState(.loading)

  static var previews: some View { TestView("Default") TestView("Loading") .previewState(.loading) }

  
  

# Generate snapshot tests prefire tests # Generate playbook models prefire playbook

Run prefire tests --help or prefire playbook --help for more options.

See detailed configuration in the Configuration guide

test_configuration: target: MyApp playbook_configuration: preview_default_enabled: true

When preparing for distribution, you may want to exclude your PreviewProvider and mock data from release builds. This can be achieved by wrapping them in #if DEBUG compiler directives. Alternatively, you can pass a compiler flag to exclude PreviewModels from release builds.

To exclude PreviewModels using Swift Package Manager, pass the PLAYBOOK_DISABLED swift setting in the package that links PrefirePlaybookPlugin:

swiftSettings: [ .define("PLAYBOOK_DISABLED", .when(configuration: .release)), ]

If you are using Xcode, you can pass the compiler flag in the Xcode build settings:

SWIFT_ACTIVE_COMPILATION_CONDITIONS = PLAYBOOK_DISABLED; 

• PrefireCore — AST + preview parsing, caching, logic
• PrefireGenerator — handles stencil templating + snapshot generation
• PrefireCacheManager — unifies caching for Types and Previews
• PrefireTestsPlugin / PrefirePlaybookPlugin — SPM/Xcode integrations
• prefire — CLI entry point, calls shared generator code

• Swift 5.6 or higher
• Xcode 14.0 or higher
• iOS 14 or higher

NavigationView in Preview not supported for Playbook

• Consider using other views or layouts for your Playbook needs.

Running Prefire via CI

• To run Prefire via Continuous Integration (CI), you need to configure permissions: defaults write com.apple.dt.Xcode IDESkipPackagePluginFingerprintValidatation -bool YES

Xcode is unable to generate tests in a custom path.

• To resolve this, you’ll need to disable the sandbox for file generation by running the following command in your terminal: defaults write com.apple.dt.Xcode IDEPackageSupportDisablePluginExecutionSandbox -bool YES

We welcome contributions! Please follow these steps:

1. Fork the repository
2. Create a feature branch
3. Submit a Pull Request

Prefire is released under the Apache License 2.0. See LICENSE for details.