feat: add function package for funcational programming

function/function_test.go

@@ -0,0 +1,95 @@
+package function
+
+import (
+	"fmt"
+	"reflect"
+	"testing"
+	"time"
+)
+
+func TestAfter(t *testing.T) {
+	arr := []string{"a", "b"}
+	f := After(len(arr), func(i int) int {
+		fmt.Println("print done")
+		return i
+	})
+	type cb func(args ...interface{}) []reflect.Value
+	print := func(i int, s string, fn cb) {
+		fmt.Printf("print: arr[%d] is %s \n", i, s)
+		v := fn(i)
+		if v != nil {
+			vv := v[0].Int()
+			if vv != 1 {
+				t.FailNow()
+			}
+		}
+	}
+	fmt.Println("print: arr is", arr)
+	for i := 0; i < len(arr); i++ {
+		print(i, arr[i], f)
+	}
+}
+
+func TestBefore(t *testing.T) {
+	arr := []string{"a", "b", "c", "d", "e"}
+	f := Before(3, func(i int) int {
+		return i
+	})
+
+	var res []int64
+	type cb func(args ...interface{}) []reflect.Value
+	appendStr := func(i int, s string, fn cb) {
+		fmt.Printf("appendStr: arr[%d] is %s \n", i, s)
+		v := fn(i)
+		res = append(res, v[0].Int())
+	}
+
+	for i := 0; i < len(arr); i++ {
+		appendStr(i, arr[i], f)
+	}
+
+	expect := []int64{0, 1, 2, 2, 2}
+	if !reflect.DeepEqual(expect, res) {
+		t.FailNow()
+	}
+}
+
+func TestCurry(t *testing.T) {
+	add := func(a, b int) int {
+		return a + b
+	}
+	var addCurry Fn = func(values ...interface{}) interface{} {
+		return add(values[0].(int), values[1].(int))
+	}
+
+	add1 := addCurry.Curry(1)
+	v := add1(2)
+	if v != 3 {
+		t.FailNow()
+	}
+}
+
+func TestDelay(t *testing.T) {
+	var print = func(s string) {
+		fmt.Println(s)
+	}
+	Delay(2*time.Second, print, "test delay")
+}
+
+func TestSchedule(t *testing.T) {
+	var res []string
+	appendStr := func(s string) {
+		fmt.Println(s)
+		res = append(res, s)
+	}
+
+	stop := Schedule(1*time.Second, appendStr, "*")
+	time.Sleep(5 * time.Second)
+	close(stop)
+
+	expect := []string{"*", "*", "*", "*", "*"}
+	if !reflect.DeepEqual(expect, res) {
+		t.FailNow()
+	}
+	fmt.Println("done")
+}