1 files changed, 37 insertions, 0 deletions
diff --git a/reduce_test.go b/reduce_test.go
new file mode 100644
index 0000000..8df58e1
--- /dev/null
+++ b/reduce_test.go
@@ -0,0 +1,37 @@
+package collection
+
+import (
+	"reflect"
+	"testing"
+)
+
+func TestReduce(t *testing.T) {
+	type args struct {
+		collection  []int
+		cb          func(previous int, current int, idx int) int
+		accumulator int
+	}
+	tests := []struct {
+		name string
+		args args
+		want int
+	}{
+		{
+			name: "Sum",
+			args: args{
+				collection: []int{1, 2, 3, 4, 5, 6},
+				cb: func(previous, current, idx int) int {
+					return previous + current
+				},
+			},
+			want: 21,
+		},
+	}
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			if got := Reduce(tt.args.collection, tt.args.cb, tt.args.accumulator); !reflect.DeepEqual(got, tt.want) {
+				t.Errorf("Reduce() = %v, want %v", got, tt.want)
+			}
+		})
+	}
+}