[stdlib] Update tests for new partition APIs

Special thanks to @aschwaighofer for help with these tests and fix-its!

Author: natecook1000

stdlib/private/StdlibCollectionUnittest/CheckMutableCollectionType.swift.gyb

@@ -907,16 +907,20 @@ func checkPartition_${'Predicate' if predicate else 'WhereElementIsComparable'}(
 
   var c = makeWrappedCollectionWithComparableElement(elements)
 %   end
-
+  let pivotElt  = c.first
+  var pivot = c.startIndex
 %   if predicate:
   let closureLifetimeTracker = LifetimeTracked(0)
-  let pivot = c.partition() {
-    (lhs, rhs) in
-    _blackHole(closureLifetimeTracker)
-    return extract(lhs).value < extract(rhs).value
+  if let first = pivotElt {
+    pivot = c.partition(by: {
+      val in
+      _blackHole(closureLifetimeTracker)
+      return !(extract(val).value < extract(first).value) })
   }
 %   else:
-  let pivot = c.partition()
+  if let first = c.first {
+    pivot = c.partition(by: { !($0 < first) })
+  }
 %   end
 
   // Check that we didn't lose any elements.
@@ -927,12 +931,12 @@ func checkPartition_${'Predicate' if predicate else 'WhereElementIsComparable'}(
     // All the elements in the first partition are less than the pivot
     // value.
     for i in c[c.startIndex..<pivot].indices {
-      expectLT(extract(c[i]).value, extract(c[pivot]).value)
+      expectLT(extract(c[i]).value, extract(pivotElt!).value)
     }
     // All the elements in the second partition are greater or equal to
     // the pivot value.
     for i in c[pivot..<c.endIndex].indices {
-      expectLE(extract(c[pivot]).value, extract(c[i]).value)
+      expectLE(extract(pivotElt!).value, extract(c[i]).value)
     }
   }
 }
@@ -988,13 +992,18 @@ self.test("\(testNamePrefix).partition/DispatchesThrough_withUnsafeMutableBuffer
 
 %   if predicate:
   let closureLifetimeTracker = LifetimeTracked(0)
-  let pivot = lc.partition() {
-    (lhs, rhs) in
-    _blackHole(closureLifetimeTracker)
-    return extract(lhs).value < extract(rhs).value
+  var pivot = lc.startIndex
+  if let first = c.first {
+    pivot = lc.partition(by: {
+      val in
+      _blackHole(closureLifetimeTracker)
+      return !(extract(val).value < extract(first).value) })
   }
 %   else:
-  let pivot = lc.partition()
+  var pivot = lc.startIndex
+  if let first = lc.first {
+    pivot = lc.partition(by: { !($0 < first) })
+  }
 %   end
 
   expectEqual(

test/1_stdlib/Renames.swift

@@ -72,11 +72,13 @@ func _CollectionAlgorithms<C : MutableCollection, I>(c: C, i: I) where C : Rando
   var c = c
   _ = c.partition(i..<i) { _, _ in true } // expected-error {{slice the collection using the range, and call partition(by:)}} {{none}}
   c.sortInPlace { _, _ in true } // expected-error {{'sortInPlace' has been renamed to 'sort(by:)'}} {{5-16=sort}} {{none}}
+  _ = c.partition { _, _ in true } // expected-error {{call partition(by:)}} {{none}}
 }
 
 func _CollectionAlgorithms<C : MutableCollection, I>(c: C, i: I) where C : RandomAccessCollection, C.Iterator.Element : Comparable, C.Index == I {
   var c = c
-  _ = c.partition(i..<i) // expected-error {{slice the collection using the range, and call partition()}} {{none}}
+  _ = c.partition() // expected-error {{call partition(by:)}} {{none}}
+  _ = c.partition(i..<i) // expected-error {{slice the collection using the range, and call partition(by:)}} {{none}}
   c.sortInPlace() // expected-error {{'sortInPlace()' has been renamed to 'sort()'}} {{5-16=sort}} {{none}}
 }
 

test/1_stdlib/sort_integers.swift

@@ -36,7 +36,7 @@ func randomize(_ size: Int, _ verify: ([Int]) -> Void) {
   var arr : [Int] = []
   var N = 1
   var M = 1
-  for i in 0..<size {
+  for _ in 0..<size {
     N = N * 19 % 1024
     M = (N + M) % size
     arr.append(N)
@@ -79,19 +79,24 @@ print("Test1 - Done")
 let partition_verifier: ([Int]) -> Void = {
     var y = $0
     // Partition() returns the index to the pivot value.
-    let idx = y.partition()
-    // Check that all of the elements in the first partition are smaller or
-    // equal to the pivot value.
+    var idx = y.startIndex
+    var pivot = -1
+    if let first = y.first {
+      pivot = first
+      idx = y.partition(by: { $0 >= first })
+    }
+    // Check that all of the elements in the first partition are smaller than
+    // the pivot value.
     for i in 0..<idx {
-      if y[i] > y[idx]  {
+      if y[i] >= pivot  {
         print("Error!\n", terminator: "")
         return
       }
     }
     // Check that all of the elements in the second partition are greater or
     // equal to the pivot value.
     for i in idx..<y.count - 1 {
-      if y[i] < y[idx]  {
+      if y[i] < pivot  {
         print("Error!\n", terminator: "")
         return
       }

test/Interpreter/protocol_extensions.swift

@@ -76,7 +76,10 @@ extension MutableCollection
   where Self: RandomAccessCollection, Self.Iterator.Element : Comparable {
 
   public final mutating func myPartition() -> Index {
-    return self.partition()
+    if let first = self.first {
+      return self.partition(by: { $0 >= first})
+    }
+    return self.startIndex
   }
 }
 

validation-test/stdlib/Algorithm.swift

@@ -149,7 +149,10 @@ Algorithm.test("invalidOrderings") {
   withInvalidOrderings {
     var a: A<Int>
     a = randomArray()
-    _ = a.partition(by: $0)
+    let lt = $0
+    if let first = a.first {
+      _ = a.partition(by: { !lt($0, first) })
+    }
   }
   /*
   // FIXME: Disabled due to <rdar://problem/17734737> Unimplemented:

validation-test/stdlib/Sort.swift.gyb

@@ -153,7 +153,8 @@ Algorithm.test("sort/CollectionsWithUnusualIndices") {
 
 Algorithm.test("partition/CrashOnSingleElement") {
   var a = DefaultedMutableRandomAccessCollection([10])
-  expectEqual(a.startIndex, a.partition())
+  let first = a.first!
+  expectEqual(a.startIndex, a.partition(by: {$0 >= first}))
 }
 
 runAllTests()