Adds ability to generate arbitrary Dates and UUIDs

.travis.yml

@@ -32,13 +32,13 @@ matrix:
     - os: linux
       language: generic
       sudo: required
-      dist: trusty
+      dist: xenial
       before_install:
         - git submodule update --init --recursive
         - wget -q -O - https://swift.org/keys/all-keys.asc | gpg --import -
-        - wget https://swift.org/builds/swift-5.0-release/ubuntu1404/swift-5.0-RELEASE/swift-5.0-RELEASE-ubuntu14.04.tar.gz
-        - tar xzf swift-5.0-RELEASE-ubuntu14.04.tar.gz
-        - export PATH=${PWD}/swift-5.0-RELEASE-ubuntu14.04/usr/bin:"${PATH}"
+        - wget https://swift.org/builds/swift-5.2.4-release/ubuntu1604/swift-5.2.4-RELEASE/swift-5.2.4-RELEASE-ubuntu16.04.tar.gz
+        - tar xzf swift-5.2.4-RELEASE-ubuntu16.04.tar.gz
+        - export PATH=${PWD}/swift-5.2.4-RELEASE-ubuntu16.04/usr/bin:"${PATH}"
         - pushd Utilities
         - ./compile.sh
         - popd

Sources/SwiftCheck/Arbitrary.swift

@@ -370,6 +370,62 @@ extension Mirror : Arbitrary {
 	}
 }
 
+import Foundation
+
+extension Date: Arbitrary {
+    public static var arbitrary: Gen<Date> {
+        return TimeInterval.arbitrary.map(Date.init(timeIntervalSinceNow:))
+    }
+}
+
+extension UUID: Arbitrary {
+	/// Returns a generator of `UUID` values.
+    public static var arbitrary: Gen<UUID> {
+        return Gen.compose { composer in
+            var bytes = (0..<16).map { _ in composer.generate(using: UInt8.arbitrary) }
+            bytes[7] = bytes[7] | 0b01000000 // UUID version 4
+            bytes[9] = bytes[9] | 0b01000000 // clock_seq_hi_and_reserved
+
+            let part1 = Data(bytes[0..<4]).hexEncodedString()
+            let part2 = Data(bytes[4..<6]).hexEncodedString()
+            let part3 = Data(bytes[6..<8]).hexEncodedString()
+            let part4 = Data(bytes[8..<10]).hexEncodedString()
+            let part5 = Data(bytes[10..<16]).hexEncodedString()
+
+            return UUID(uuidString: part1 + "-" + part2 + "-" + part3 + "-" + part4 + "-" + part5)!
+        }
+    }
+}
+
+extension Data {
+
+	/// Creates a new `Data` instance using the hexadecimal-encoded string.
+	///
+	/// - Parameter string: A string with even non-zero length containing only digits or a/A through f/F.
+    public init?(hexEncoded string: String) {
+        if string.count == 0 || string.count % 2 != 0 { return nil }
+
+        var bytes = [UInt8]()
+        var start = string.startIndex
+        while start < string.endIndex {
+            let chunkEnd = string.index(start, offsetBy: 2)
+            let chunk = string[start..<chunkEnd]
+            guard let byte = UInt8(chunk, radix: 16) else { return nil }
+            bytes.append(byte)
+            start = chunkEnd
+        }
+        self.init(bytes)
+    }
+
+
+	/// Creates a hexadecimal string representation of the data.
+	///
+	/// - Returns:A string with even non-zero length containing only digits or a/A through f/F.
+    public func hexEncodedString() -> String {
+        return [UInt8](self).map { String(format: "%.2x", $0) }.reduce("", {$0+$1})
+    }
+}
+
 #if os(Linux)
 	import Glibc
 #else

SwiftCheck.xcodeproj/project.pbxproj

@@ -7,6 +7,9 @@
 	objects = {
 
 /* Begin PBXBuildFile section */
+		02135F9324AA3BB300E33BF1 /* ArbitrarySpec.swift in Sources */ = {isa = PBXBuildFile; fileRef = 02135F9224AA3BA800E33BF1 /* ArbitrarySpec.swift */; };
+		02135F9424AA3BB300E33BF1 /* ArbitrarySpec.swift in Sources */ = {isa = PBXBuildFile; fileRef = 02135F9224AA3BA800E33BF1 /* ArbitrarySpec.swift */; };
+		02135F9524AA3BB400E33BF1 /* ArbitrarySpec.swift in Sources */ = {isa = PBXBuildFile; fileRef = 02135F9224AA3BA800E33BF1 /* ArbitrarySpec.swift */; };
 		6A761B9E1F14E92100A7D74F /* Arbitrary.swift in Sources */ = {isa = PBXBuildFile; fileRef = 6A761B771F14E91400A7D74F /* Arbitrary.swift */; };
 		6A761B9F1F14E92100A7D74F /* Cartesian.swift in Sources */ = {isa = PBXBuildFile; fileRef = 6A761B781F14E91400A7D74F /* Cartesian.swift */; };
 		6A761BA01F14E92100A7D74F /* Check.swift in Sources */ = {isa = PBXBuildFile; fileRef = 6A761B791F14E91400A7D74F /* Check.swift */; };
@@ -176,6 +179,7 @@
 /* End PBXCopyFilesBuildPhase section */
 
 /* Begin PBXFileReference section */
+		02135F9224AA3BA800E33BF1 /* ArbitrarySpec.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = ArbitrarySpec.swift; sourceTree = "<group>"; };
 		6A761B751F14E91400A7D74F /* Info.plist */ = {isa = PBXFileReference; lastKnownFileType = text.plist.xml; path = Info.plist; sourceTree = "<group>"; };
 		6A761B771F14E91400A7D74F /* Arbitrary.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = Arbitrary.swift; sourceTree = "<group>"; };
 		6A761B781F14E91400A7D74F /* Cartesian.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = Cartesian.swift; sourceTree = "<group>"; };
@@ -328,6 +332,7 @@
 		6A761B8C1F14E91500A7D74F /* SwiftCheckTests */ = {
 			isa = PBXGroup;
 			children = (
+				02135F9224AA3BA800E33BF1 /* ArbitrarySpec.swift */,
 				6A761B8D1F14E91500A7D74F /* BooleanIdentitySpec.swift */,
 				6A761B8E1F14E91500A7D74F /* CartesianSpec.swift */,
 				6A761B8F1F14E91500A7D74F /* ComplexSpec.swift */,
@@ -676,6 +681,7 @@
 				8235D34C1F72DD0B00207FA1 /* Diagnostics.swift in Sources */,
 				8235D34D1F72DD0B00207FA1 /* EditDistance.swift in Sources */,
 				8235D34E1F72DD0B00207FA1 /* FileCheck.swift in Sources */,
+				02135F9524AA3BB400E33BF1 /* ArbitrarySpec.swift in Sources */,
 				8235D34F1F72DD0B00207FA1 /* Pattern.swift in Sources */,
 				6A761C021F14E93B00A7D74F /* SimpleSpec.swift in Sources */,
 				6A761C031F14E93B00A7D74F /* TestSpec.swift in Sources */,
@@ -727,6 +733,7 @@
 				8235D3561F72DD2200207FA1 /* CheckString.swift in Sources */,
 				8235D3571F72DD2200207FA1 /* ColoredStream.swift in Sources */,
 				8235D3581F72DD2200207FA1 /* Diagnostics.swift in Sources */,
+				02135F9324AA3BB300E33BF1 /* ArbitrarySpec.swift in Sources */,
 				8235D3591F72DD2200207FA1 /* EditDistance.swift in Sources */,
 				8235D35A1F72DD2200207FA1 /* FileCheck.swift in Sources */,
 				8235D35B1F72DD2200207FA1 /* Pattern.swift in Sources */,
@@ -778,6 +785,7 @@
 				8235D3501F72DD1B00207FA1 /* CheckString.swift in Sources */,
 				8235D3511F72DD1B00207FA1 /* ColoredStream.swift in Sources */,
 				8235D3521F72DD1B00207FA1 /* Diagnostics.swift in Sources */,
+				02135F9424AA3BB300E33BF1 /* ArbitrarySpec.swift in Sources */,
 				8235D3531F72DD1B00207FA1 /* EditDistance.swift in Sources */,
 				8235D3541F72DD1B00207FA1 /* FileCheck.swift in Sources */,
 				8235D3551F72DD1B00207FA1 /* Pattern.swift in Sources */,

Tests/LinuxMain.swift

@@ -12,6 +12,7 @@ import XCTest
 
 #if !os(macOS)
 XCTMain([
+	ArbitrarySpec.allTests,
 	BooleanIdentitySpec.allTests,
 	ComplexSpec.allTests,
 	DiscardSpec.allTests,

Tests/SwiftCheckTests/ArbitrarySpec.swift

@@ -0,0 +1,34 @@
+import SwiftCheck
+import XCTest
+import Foundation
+#if SWIFT_PACKAGE
+import FileCheck
+#endif
+
+class ArbitrarySpec : XCTestCase {
+	func testAll() {
+		XCTAssert(fileCheckOutput {
+			// CHECK: *** Passed 100 tests
+			// CHECK-NEXT: .
+			property("generates arbitrary `Date`s") <- forAll { (_ : Date) in
+				// The fact that we can return something here means that
+				// generating the Date succeeded
+				return true
+			}
+
+			// CHECK: *** Passed 100 tests
+			// CHECK-NEXT: .
+			property("generates arbitrary `UUID`s") <- forAll { (_ : UUID) in
+				// The fact that we can return something here means that
+				// generating the UUID succeeded
+				return true
+			}
+		})
+	}
+
+	#if !(os(macOS) || os(iOS) || os(watchOS) || os(tvOS))
+	static var allTests = testCase([
+		("testAll", testAll),
+	])
+	#endif
+}