Refactor

Author: x-sheep

Sources/PropertyBased/Generator.swift

@@ -315,9 +315,3 @@ extension Generator {
         )
     }
 }
-
-/// Errors that may be thrown by a generator.
-public enum GeneratorError: Error {
-    /// A generator failed to generate a valid value within the specified amount of attempts.
-    case runLimitExceeded(Int)
-}

Sources/PropertyBased/GeneratorError.swift

@@ -0,0 +1,29 @@
+//
+//  GeneratorError.swift
+//  PropertyBased
+//
+//  Created by Lennard Sprong on 13/08/2026.
+//
+
+#if canImport(Foundation)
+import Foundation
+#endif
+
+/// Errors that may be thrown by a generator.
+public enum GeneratorError: Equatable, Error, CustomStringConvertible {
+    /// A generator failed to generate a valid value within the specified amount of attempts.
+    case runLimitExceeded(Int)
+
+    public var description: String {
+        switch self {
+        case .runLimitExceeded(let count):
+            "Failed to generate a valid input after \(count) attempts. Check if the Generator is filtering too many values."
+        }
+    }
+}
+
+#if canImport(Foundation)
+extension GeneratorError: LocalizedError {
+    public var localizedDescription: String { description }
+}
+#endif

Sources/PropertyBased/PropertyCheck.swift

@@ -131,16 +131,9 @@ public func propertyCheck<InputValue, ResultValue>(
         do {
             (inputValue, resultValue) = try input.runFull(&rng, runLimit ?? 10000)
         } catch {
-            var failureMessage: String
-            if let genError = error as? GeneratorError, case .runLimitExceeded(let count) = genError {
-                failureMessage =
-                    "Failed to generate a valid input after \(count) attempts. Check if the Generator is filtering too many values."
-
-                if runLimit == nil {
-                    failureMessage += "\n\nYou can add `.maxAttempts()` to the Test or Suite to increase the limit."
-                }
-            } else {
-                failureMessage = "Unknown error during generation: \(error)"
+            var failureMessage = String(describing: error)
+            if runLimit == nil, let genError = error as? GeneratorError, case .runLimitExceeded = genError {
+                failureMessage += "\n\nYou can add `.maximumAttempts()` to the Test or Suite to increase the limit."
             }
 
             if fixedRng == nil {

Tests/PropertyBasedTests/MaxAttemptsTraitTest.swift

@@ -0,0 +1,56 @@
+//
+//  MaximumAttemptsTraitTest.swift
+//  PropertyBased
+//
+//  Created by Lennard Sprong on 10/08/2026.
+//
+
+import Testing
+
+@testable import PropertyBased
+
+@Suite struct MaximumAttemptsTraitTest {
+    @Test func testRunUsesLimit() {
+        let useless = Gen.always(false).filter { $0 }
+
+        #expect(throws: GeneratorError.runLimitExceeded(25)) {
+            var rng = Xoshiro()
+            _ = try useless.run(using: &rng, limit: 25)
+        }
+    }
+
+    @Test func testTraitCanModifyCount() async throws {
+        let useless = Gen.always(false).filter { $0 }
+
+        let trait = MaximumAttemptsTrait.maximumAttempts(20)
+        let scope = try #require(trait.scopeProvider(for: Test.current!, testCase: Test.Case.current))
+
+        let issues = await gatherIssues {
+            try await scope.provideScope(for: Test.current!, testCase: Test.Case.current) {
+                await propertyCheck(input: useless) { _ in
+                    try #require(Bool(false), "block must not be called")
+                }
+            }
+        }
+        #expect(issues.count == 1)
+        #expect(
+            issues.contains(where: {
+                $0.contains("20 attempts") && !$0.contains("maximumAttempts()")
+            }))
+    }
+
+    @Test func testTraitSuggestion() async throws {
+        let useless = Gen.always(false).filter { $0 }
+        let issues = await gatherIssues {
+            await propertyCheck(input: useless) { _ in
+                try #require(Bool(false), "block must not be called")
+            }
+        }
+
+        #expect(issues.count == 1)
+        #expect(
+            issues.contains(where: {
+                $0.contains("maximumAttempts()")
+            }))
+    }
+}