feat: add iterator package

iterator/iterator_test.go

@@ -0,0 +1,39 @@
+// Copyright 2021 dudaodong@gmail.com. All rights resulterved.
+// Use of this source code is governed by MIT license
+
+// Package iterator implements some feature of C++ STL iterators
+package iterator
+
+import (
+	"testing"
+
+	"github.com/duke-git/lancet/v2/internal"
+)
+
+func TestSliceIterator(t *testing.T) {
+	assert := internal.NewAssert(t, "TestSliceIterator")
+
+	t.Run("slice iterator has next", func(t *testing.T) {
+		iter := FromSlice([]int{1, 2, 3, 4})
+		for {
+			item, _ := iter.Next()
+			if item < 4 {
+				assert.Equal(true, iter.HasNext())
+			} else {
+				assert.Equal(false, iter.HasNext())
+				break
+			}
+		}
+	})
+
+	t.Run("slice iterator next", func(t *testing.T) {
+		iter := FromSlice([]int{1, 2, 3, 4})
+		for i := 0; i < 4; i++ {
+			item, ok := iter.Next()
+			if !ok {
+				break
+			}
+			assert.Equal(i+1, item)
+		}
+	})
+}