1 files changed, 184 insertions, 0 deletions
diff --git a/src/slices/iter_test.go b/src/slices/iter_test.go
new file mode 100644
index 0000000000..67520f60c9
--- /dev/null
+++ b/src/slices/iter_test.go
@@ -0,0 +1,184 @@
+// Copyright 2024 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package slices_test
+
+import (
+	"iter"
+	"math/rand/v2"
+	. "slices"
+	"testing"
+)
+
+func TestAll(t *testing.T) {
+	for size := 0; size < 10; size++ {
+		var s []int
+		for i := range size {
+			s = append(s, i)
+		}
+		ei, ev := 0, 0
+		cnt := 0
+		for i, v := range All(s) {
+			if i != ei || v != ev {
+				t.Errorf("at iteration %d got %d, %d want %d, %d", cnt, i, v, ei, ev)
+			}
+			ei++
+			ev++
+			cnt++
+		}
+		if cnt != size {
+			t.Errorf("read %d values expected %d", cnt, size)
+		}
+	}
+}
+
+func TestBackward(t *testing.T) {
+	for size := 0; size < 10; size++ {
+		var s []int
+		for i := range size {
+			s = append(s, i)
+		}
+		ei, ev := size-1, size-1
+		cnt := 0
+		for i, v := range Backward(s) {
+			if i != ei || v != ev {
+				t.Errorf("at iteration %d got %d, %d want %d, %d", cnt, i, v, ei, ev)
+			}
+			ei--
+			ev--
+			cnt++
+		}
+		if cnt != size {
+			t.Errorf("read %d values expected %d", cnt, size)
+		}
+	}
+}
+
+func TestValues(t *testing.T) {
+	for size := 0; size < 10; size++ {
+		var s []int
+		for i := range size {
+			s = append(s, i)
+		}
+		ev := 0
+		cnt := 0
+		for v := range Values(s) {
+			if v != ev {
+				t.Errorf("at iteration %d got %d want %d", cnt, v, ev)
+			}
+			ev++
+			cnt++
+		}
+		if cnt != size {
+			t.Errorf("read %d values expected %d", cnt, size)
+		}
+	}
+}
+
+func testSeq(yield func(int) bool) {
+	for i := 0; i < 10; i += 2 {
+		if !yield(i) {
+			return
+		}
+	}
+}
+
+var testSeqResult = []int{0, 2, 4, 6, 8}
+
+func TestAppendSeq(t *testing.T) {
+	s := AppendSeq([]int{1, 2}, testSeq)
+	want := append([]int{1, 2}, testSeqResult...)
+	if !Equal(s, want) {
+		t.Errorf("got %v, want %v", s, want)
+	}
+}
+
+func TestCollect(t *testing.T) {
+	s := Collect(testSeq)
+	want := testSeqResult
+	if !Equal(s, want) {
+		t.Errorf("got %v, want %v", s, want)
+	}
+}
+
+var iterTests = [][]string{
+	nil,
+	{"a"},
+	{"a", "b"},
+	{"b", "a"},
+	strs[:],
+}
+
+func TestValuesAppendSeq(t *testing.T) {
+	for _, prefix := range iterTests {
+		for _, s := range iterTests {
+			got := AppendSeq(prefix, Values(s))
+			want := append(prefix, s...)
+			if !Equal(got, want) {
+				t.Errorf("AppendSeq(%v, Values(%v)) == %v, want %v", prefix, s, got, want)
+			}
+		}
+	}
+}
+
+func TestValuesCollect(t *testing.T) {
+	for _, s := range iterTests {
+		got := Collect(Values(s))
+		if !Equal(got, s) {
+			t.Errorf("Collect(Values(%v)) == %v, want %v", s, got, s)
+		}
+	}
+}
+
+func TestSorted(t *testing.T) {
+	s := Sorted(Values(ints[:]))
+	if !IsSorted(s) {
+		t.Errorf("sorted %v", ints)
+		t.Errorf("   got %v", s)
+	}
+}
+
+func TestSortedFunc(t *testing.T) {
+	s := SortedFunc(Values(ints[:]), func(a, b int) int { return a - b })
+	if !IsSorted(s) {
+		t.Errorf("sorted %v", ints)
+		t.Errorf("   got %v", s)
+	}
+}
+
+func TestSortedStableFunc(t *testing.T) {
+	n, m := 1000, 100
+	data := make(intPairs, n)
+	for i := range data {
+		data[i].a = rand.IntN(m)
+	}
+	data.initB()
+
+	s := intPairs(SortedStableFunc(Values(data), intPairCmp))
+	if !IsSortedFunc(s, intPairCmp) {
+		t.Errorf("SortedStableFunc didn't sort %d ints", n)
+	}
+	if !s.inOrder(false) {
+		t.Errorf("SortedStableFunc wasn't stable on %d ints", n)
+	}
+
+	// iterVal converts a Seq2 to a Seq.
+	iterVal := func(seq iter.Seq2[int, intPair]) iter.Seq[intPair] {
+		return func(yield func(intPair) bool) {
+			for _, v := range seq {
+				if !yield(v) {
+					return
+				}
+			}
+		}
+	}
+
+	s = intPairs(SortedStableFunc(iterVal(Backward(data)), intPairCmp))
+	if !IsSortedFunc(s, intPairCmp) {
+		t.Errorf("SortedStableFunc didn't sort %d reverse ints", n)
+	}
+	if !s.inOrder(true) {
+		t.Errorf("SortedStableFunc wasn't stable on %d reverse ints", n)
+	}
+}