Add "EnableShrinking" package trait for changing default behavior

Author: x-sheep

Package.swift

@@ -2,6 +2,12 @@
 
 import PackageDescription
 
+#if swift(>=6.2)
+let shrinkByDefault = true
+#else
+let shrinkByDefault = false
+#endif
+
 let package = Package(
     name: "PropertyBased",
     platforms: [.macOS(.v10_15), .iOS(.v13), .tvOS(.v13), .watchOS(.v6), .macCatalyst(.v13), .visionOS(.v1)],
@@ -11,6 +17,14 @@ let package = Package(
             targets: ["PropertyBased"]
         )
     ],
+    traits: [
+        .default(enabledTraits: shrinkByDefault ? ["EnableShrinking"] : []),
+        .trait(
+            name: "EnableShrinking",
+            description:
+                "This trait enables the shrinker by default. Regardless of this trait being set, you can use the shrinking() TestTrait to enable/disable the shrinker on a case-by-case basis."
+        ),
+    ],
     dependencies: [],
     targets: [
         .target(

README.md

@@ -5,9 +5,15 @@
 
 PropertyBased is a Swift 6 library that enables Property-Based Testing in `swift-testing`, similar to QuickCheck for Haskell or FsCheck for F# and C#.
 
-Property-Based Testing can be used as an alternative for (or in addition to) testing with hardcoded values. Run tests with composable random inputs, then easily switch to specific failing cases just by adding a single line.
+Property-Based Testing can be used as an alternative for (or in addition to) testing with hardcoded values.
 
-This project aims to support all platforms which can run Swift Testing, including platforms without [Foundation](https://developer.apple.com/documentation/foundation) support.
+## Features
+
+* Works through Swift Testing, including on platforms without [Foundation](https://developer.apple.com/documentation/foundation) support
+* Contains a set of generators for all commonly-used types in the Swift standard library
+* Compose generators to create more complex inputs
+* Automatically [shrink](#shrinking) large inputs to easily digestable inputs
+* Switch to specific failing cases with just [a single line](#using-fixed-seeds)
 
 ## Requirements
 
@@ -17,6 +23,21 @@ This project aims to support all platforms which can run Swift Testing, includin
   * iOS/tvOS 13.0+, watchOS 6.0+, visionOS 1.0+
   * Linux, Windows, etc.
 
+## Installation
+
+### When writing a Swift package:
+
+Add the following line to the dependencies array in your `Package.swift` file:
+```swift
+.package(url: "https://github.com/x-sheep/swift-property-based.git", from: "1.0.0")
+```
+
+### When writing an Xcode project:
+
+1. Open your Project
+2. Go to File > Add Package Dependencies...
+3. Paste the repository URL in the search field: `https://github.com/x-sheep/swift-property-based.git`
+
 ## Examples
 
 Simple example:
@@ -77,9 +98,6 @@ func failsSometimes() async {
 
 # Shrinking
 
-> [!NOTE] 
-> This feature is experimental, and disabled by default. The shrinking output will be very verbose, due to a limitation in Swift Testing.
-
 When a failing case has been found, it's possible that the input is large and contrived, such as arrays with many elements. When _shrinking_ is enabled, PropertyBased will repeat a failing test until it finds the smallest possible input that still causes a failure.
 
 For example, the following test fails when the given numbers sum to a value above a certain threshold:
@@ -95,16 +113,17 @@ For example, the following test fails when the given numbers sum to a value abov
 
 The generator could come up with an array like `[63, 61, 33, 53, 97, 68, 23, 16]`, which sums to `414`. Ideally, we want to have an input that sums to exactly `250`.
 
-Enable the shrinker by adding the `shrinking` trait:
+After shrinking, the new failing case is `[46, 97, 68, 23, 16]`, which sums to exactly `250`. The first few elements have been removed, while the middle element has been reduced to be closer to the edge. PropertyBased will output both the shrunk input and the original input:
 
-```swift
-@Test(.shrinking) func checkSumInRange() async
 ```
-
-After shrinking, the new failing case is `[46, 97, 68, 23, 16]`, which sums to exactly `250`. The first few elements have been removed, while the middle element has been reduced to be closer to the edge.
+Failure occured with input [46, 97, 68, 23, 16].
+(shrunk down from [63, 61, 33, 53, 97, 68, 23, 16] after 7 iterations)
+```
 
 When using the built-in generators and the `zip` function, shrinkers will also be composed.
 
+The `.shrinking` TestTrait or SuiteTrait can be used to override shrinking behavior.
+
 # License
 
 Copyright (c) 2025 Lennard Sprong.

Sources/PropertyBased/EnableShrinkTrait.swift

@@ -11,7 +11,7 @@ import Testing
 ///
 /// Use ``shrinking(_:)`` to construct an instance of this trait.
 ///
-/// > Note: This feature is experimental, and disabled by default. The shrinking output will be very verbose, due to a limitation in Swift Testing.
+/// The Swift Package Trait `"EnableShrinking"` controls if shrinking defaults to being enabled. On Swift 6.2, this is set by default.
 public struct EnableShrinkTrait: TestTrait, SuiteTrait, TestScoping {
     @_documentation(visibility: internal)
     public var isRecursive: Bool { false }
@@ -24,16 +24,25 @@ public struct EnableShrinkTrait: TestTrait, SuiteTrait, TestScoping {
         }
     }
 
+    #if EnableShrinking
+    @TaskLocal static var isEnabled = true
+    #else
     @TaskLocal static var isEnabled = false
+    #endif
 
     var shouldEnable: Bool
 }
 
 extension Trait where Self == EnableShrinkTrait {
     /// Enable shrinking within this test or test suite.
+    ///
+    /// The Swift Package Trait `"EnableShrinking"` controls if shrinking defaults to being enabled. On Swift 6.2, this is set by default.
     public static var shrinking: Self { shrinking(true) }
 
     /// Enable or disable shrinking within this test or test suite.
+    ///
+    /// The Swift Package Trait `"EnableShrinking"` controls if shrinking defaults to being enabled. On Swift 6.2, this is set by default.
+    ///
     /// - Parameter enabled: Whether to enable shrinking.
     /// - Returns: An instance of ``EnableShrinkTrait``.
     public static func shrinking(_ enabled: Bool = true) -> Self {