initial checkin

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

option/option_test.go

@@ -0,0 +1,116 @@
+package option
+
+import (
+	"fmt"
+	"testing"
+
+	F "github.com/ibm/fp-go/function"
+	"github.com/ibm/fp-go/internal/utils"
+	"github.com/stretchr/testify/assert"
+)
+
+func TestReduce(t *testing.T) {
+
+	assert.Equal(t, 2, F.Pipe1(None[int](), Reduce(utils.Sum, 2)))
+	assert.Equal(t, 5, F.Pipe1(Some(3), Reduce(utils.Sum, 2)))
+}
+
+func TestIsNone(t *testing.T) {
+	assert.True(t, IsNone(None[int]()))
+	assert.False(t, IsNone(Of(1)))
+}
+
+func TestIsSome(t *testing.T) {
+	assert.True(t, IsSome(Of(1)))
+	assert.False(t, IsSome(None[int]()))
+}
+
+func TestMapOption(t *testing.T) {
+
+	assert.Equal(t, F.Pipe1(Some(2), Map(utils.Double)), Some(4))
+
+	assert.Equal(t, F.Pipe1(None[int](), Map(utils.Double)), None[int]())
+}
+
+func TestTryCachOption(t *testing.T) {
+
+	res := TryCatch(utils.Error)
+
+	assert.Equal(t, None[int](), res)
+}
+
+func TestAp(t *testing.T) {
+	assert.Equal(t, Some(4), F.Pipe1(
+		Some(utils.Double),
+		Ap[int, int](Some(2)),
+	))
+
+	assert.Equal(t, None[int](), F.Pipe1(
+		Some(utils.Double),
+		Ap[int, int](None[int]()),
+	))
+
+	assert.Equal(t, None[int](), F.Pipe1(
+		None[func(int) int](),
+		Ap[int, int](Some(2)),
+	))
+
+	assert.Equal(t, None[int](), F.Pipe1(
+		None[func(int) int](),
+		Ap[int, int](None[int]()),
+	))
+}
+
+func TestChain(t *testing.T) {
+	f := func(n int) Option[int] { return Some(n * 2) }
+	g := func(_ int) Option[int] { return None[int]() }
+
+	assert.Equal(t, Some(2), F.Pipe1(
+		Some(1),
+		Chain(f),
+	))
+
+	assert.Equal(t, None[int](), F.Pipe1(
+		None[int](),
+		Chain(f),
+	))
+
+	assert.Equal(t, None[int](), F.Pipe1(
+		Some(1),
+		Chain(g),
+	))
+
+	assert.Equal(t, None[int](), F.Pipe1(
+		None[int](),
+		Chain(g),
+	))
+}
+
+func TestFlatten(t *testing.T) {
+	assert.Equal(t, Of(1), F.Pipe1(Of(Of(1)), Flatten[int]))
+}
+
+func TestFold(t *testing.T) {
+	f := F.Constant("none")
+	g := func(s string) string { return fmt.Sprintf("some%d", len(s)) }
+
+	fold := Fold(f, g)
+
+	assert.Equal(t, "none", fold(None[string]()))
+	assert.Equal(t, "some3", fold(Some("abc")))
+}
+
+func TestFromPredicate(t *testing.T) {
+	p := func(n int) bool { return n > 2 }
+	f := FromPredicate(p)
+
+	assert.Equal(t, None[int](), f(1))
+	assert.Equal(t, Some(3), f(3))
+}
+
+func TestAlt(t *testing.T) {
+	assert.Equal(t, Some(1), F.Pipe1(Some(1), Alt(F.Constant(Some(2)))))
+	assert.Equal(t, Some(2), F.Pipe1(Some(2), Alt(F.Constant(None[int]()))))
+	assert.Equal(t, Some(1), F.Pipe1(None[int](), Alt(F.Constant(Some(1)))))
+	assert.Equal(t, None[int](), F.Pipe1(None[int](), Alt(F.Constant(None[int]()))))
+}