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package higherorder
import (
"reflect"
"strings"
"testing"
)
func Test_Foldl(t *testing.T) {
x := Foldl(func(a, b int) int {
return a + b
}, 0, []int{1, 2, 3})
const expect = 6
if x != expect {
t.Errorf("Expected %d, got %d", expect, x)
}
}
func Test_Foldr(t *testing.T) {
x := Foldl(func(a, b int) int {
return a - b
}, 6, []int{1, 2, 3})
const expect = 0
if x != expect {
t.Errorf("Expected %d, got %d", expect, x)
}
}
func Test_Map(t *testing.T) {
{
// Map over ints, returning the square of each int.
// (Take ints, return ints.)
x := Map(func(a int) int {
return a * a
}, []int{2, 3, 4})
expected := []int{4, 9, 16}
for i, v := range x {
if v != expected[i] {
t.Errorf("Index %d: expected %d, got %d", i, expected[i], v)
}
}
}
{
// Map over strings, returning the length of each string.
// (Take ints, return strings.)
x := Map(func(a string) int {
return len([]rune(a))
}, []string{"one", "two", "three"})
expected := []int{3, 3, 5}
for i, v := range x {
if v != expected[i] {
t.Errorf("Index %d: expected %d, got %d", i, expected[i], v)
}
}
}
}
func Test_Filter(t *testing.T) {
t.Run("with string slices", func(t *testing.T) {
got := Filter(func(a string) bool {
return strings.HasPrefix(a, "t")
}, []string{"one", "two", "three"})
want := []string{"two", "three"}
if !reflect.DeepEqual(got, want) {
t.Errorf("Expected %v, got %v", want, got)
}
})
t.Run("with int slices", func(t *testing.T) {
got := Filter(func(a int) bool {
return a%2 == 0
}, []int{1, 2, 3, 4, 5})
want := []int{2, 4}
if !reflect.DeepEqual(got, want) {
t.Errorf("Expected %v, got %v", want, got)
}
})
}
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