From 5d6ecf095435d2add75a81ab8a995356c2756102 Mon Sep 17 00:00:00 2001
From: Nico Richard <nicorichard@gmail.com>
Date: Mon, 14 Feb 2022 14:59:10 -0600
Subject: [PATCH] Adds a method to allow for array shuffling (#31)

* shuffles an array of values

* Test shuffled
---
 .../Business Cards/BusinessListView.swift     |  2 +-
 .../Genything/gen/build/Gen+shuffled.swift    | 20 ++++++++++++++++
 .../GenythingTests/gen/build/GenOfTests.swift | 13 +----------
 .../gen/build/GenShuffledTests.swift          | 23 +++++++++++++++++++
 4 files changed, 45 insertions(+), 13 deletions(-)
 create mode 100644 Sources/Genything/gen/build/Gen+shuffled.swift
 create mode 100644 Tests/GenythingTests/gen/build/GenShuffledTests.swift

diff --git a/Example/GenythingExample/Pages/Business Cards/BusinessListView.swift b/Example/GenythingExample/Pages/Business Cards/BusinessListView.swift
index 1c3e11d6..a779b3f6 100644
--- a/Example/GenythingExample/Pages/Business Cards/BusinessListView.swift	
+++ b/Example/GenythingExample/Pages/Business Cards/BusinessListView.swift	
@@ -59,7 +59,7 @@ struct BusinessListView: View {
             addressLine1: Fake.Addresses.streetLine.generate(context: ctx),
             addressLine2: addressLine2Gen.generate(context: ctx)
         )
-    }.take(count: 50)
+    }.take(50)
     
     var body: some View {
         List {
diff --git a/Sources/Genything/gen/build/Gen+shuffled.swift b/Sources/Genything/gen/build/Gen+shuffled.swift
new file mode 100644
index 00000000..c9361ab1
--- /dev/null
+++ b/Sources/Genything/gen/build/Gen+shuffled.swift
@@ -0,0 +1,20 @@
+import Foundation
+
+// MARK: Build
+
+public extension Gen {
+    /// Returns: A generator which produces the result of shuffling the provided list
+    ///
+    /// - Warning: The values list must not be empty
+
+    /// - Parameter values: The values which this generator will shuffle
+    ///
+    /// - Returns: The generator
+    static func shuffled(_ values: [T]) -> Gen<[T]> {
+        assert(!values.isEmpty, "`Gen.shuffled(values:)` was invoked with an empty list of values")
+
+        return Gen<[T]> { ctx in
+            values.shuffled(using: &ctx.rng)
+        }
+    }
+}
diff --git a/Tests/GenythingTests/gen/build/GenOfTests.swift b/Tests/GenythingTests/gen/build/GenOfTests.swift
index 6de2f921..d62b01ac 100644
--- a/Tests/GenythingTests/gen/build/GenOfTests.swift
+++ b/Tests/GenythingTests/gen/build/GenOfTests.swift
@@ -2,7 +2,7 @@ import XCTest
 @testable import Genything
 
 final internal class GenOfTests: XCTestCase {
-    func test_from_createGenerator() {
+    func test_of_createGenerator() {
         let gen = Gen.of([0, 1, 2])
         let sample = gen.take()
 
@@ -11,15 +11,4 @@ final internal class GenOfTests: XCTestCase {
         XCTAssert(sample.contains(2))
         XCTAssert(sample.allSatisfy { $0 == 0 || $0 == 1 || $0 == 2 })
     }
-
-
-    func test_exhaust() {
-        let samples = Gen.exhaust([0, Int.max], then: Gen.from(0...Int.max))
-            .samples()
-
-        XCTAssertEqual(0, samples[0])
-        XCTAssertEqual(Int.max, samples[1])
-
-        print("!@# samples \(samples)")
-    }
 }
diff --git a/Tests/GenythingTests/gen/build/GenShuffledTests.swift b/Tests/GenythingTests/gen/build/GenShuffledTests.swift
new file mode 100644
index 00000000..41960f6f
--- /dev/null
+++ b/Tests/GenythingTests/gen/build/GenShuffledTests.swift
@@ -0,0 +1,23 @@
+import Foundation
+@testable import Genything
+import XCTest
+
+final internal class GenShuffledTests: XCTestCase {
+    func test_shuffled() {
+        let source = [0,1,2,3,4,5,6,7,8,9]
+
+        // Seed the context such that we can reproduce results with or without the generator
+        let seed: UInt64 = 1234
+        let context = Context(using: LinearCongruentialRandomNumberGenerator(seed: seed), originalSeed: seed)
+
+        // Take 100 shuffles
+        let shuffledViaGeneratorList = Gen.shuffled(source)
+            .take(100, context: context)
+
+        // Make sure that these shuffles match doing normal shuffles without a generator
+        var collectionsLCRNG = LinearCongruentialRandomNumberGenerator(seed: seed)
+        for shuffledViaGenerator in shuffledViaGeneratorList {
+            XCTAssertEqual(shuffledViaGenerator, source.shuffled(using: &collectionsLCRNG))
+        }
+    }
+}