fix: add ioeither

Signed-off-by: Dr. Carsten Leue <carsten.leue@de.ibm.com>

io/io_test.go

@@ -0,0 +1,58 @@
+package io
+
+import (
+	"math/rand"
+	"testing"
+
+	F "github.com/ibm/fp-go/function"
+	"github.com/ibm/fp-go/internal/utils"
+	"github.com/stretchr/testify/assert"
+)
+
+func TestMap(t *testing.T) {
+	assert.Equal(t, 2, F.Pipe1(Of(1), Map(utils.Double))())
+}
+
+func TestChain(t *testing.T) {
+	f := func(n int) IO[int] {
+		return Of(n * 2)
+	}
+	assert.Equal(t, 2, F.Pipe1(Of(1), Chain(f))())
+}
+
+func TestAp(t *testing.T) {
+	assert.Equal(t, 2, F.Pipe1(Of(utils.Double), Ap[int, int](Of(1)))())
+}
+
+func TestFlatten(t *testing.T) {
+	assert.Equal(t, 1, F.Pipe1(Of(Of(1)), Flatten[int])())
+}
+
+func TestMemoize(t *testing.T) {
+	data := Memoize(MakeIO(rand.Int))
+
+	value1 := data()
+	value2 := data()
+
+	assert.Equal(t, value1, value2)
+}
+
+func TestApFirst(t *testing.T) {
+
+	x := F.Pipe1(
+		Of("a"),
+		ApFirst[string](Of("b")),
+	)
+
+	assert.Equal(t, "a", x())
+}
+
+func TestApSecond(t *testing.T) {
+
+	x := F.Pipe1(
+		Of("a"),
+		ApSecond[string](Of("b")),
+	)
+
+	assert.Equal(t, "b", x())
+}