(filter): add integer for filter test

filter_test.go

@@ -24,6 +24,22 @@ func TestFilter(t *testing.T) {
 	}
 }
 
+func TestIntFilter(t *testing.T) {
+	intMap := gomap.New(1, 2, 3, 4, 5, 6, 7, 8, 9, 10)
+	values := []int{2, 4, 6, 8, 10}
+	mappable := intMap.Mappable()
+	filtered := mappable.Filter(func(i interface{}) bool {
+		if value, ok := i.(int); ok {
+			// Filter even numbers.
+			return value%2 == 0
+		}
+		return false
+	})
+	if !reflect.DeepEqual(mapToInt(filtered.Items()), values) {
+		t.Fail()
+	}
+}
+
 // Benchmark the filtering function.
 func BenchmarkFilter(b *testing.B) {
 	stringMap := gomap.New("test", "test1", "test2", "not_applicable", "test3")
@@ -47,8 +63,16 @@ func BenchmarkFilter(b *testing.B) {
 // Map an interface array to a string.
 func mapToString(i []interface{}) []string {
 	var strArr []string
-	for _, v :=  range i {
+	for _, v := range i {
 		strArr = append(strArr, v.(string))
 	}
 	return strArr
-}
+}
+
+func mapToInt(i []interface{}) []int {
+	var ia []int
+	for _, v := range i {
+		ia = append(ia, v.(int))
+	}
+	return ia
+}