initial checkin

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

errors/conv_test.go

@@ -0,0 +1,39 @@
+package errors
+
+import (
+	"fmt"
+	"testing"
+
+	F "github.com/ibm/fp-go/function"
+	O "github.com/ibm/fp-go/option"
+	"github.com/stretchr/testify/assert"
+)
+
+type MyError struct{}
+
+func (m *MyError) Error() string {
+	return "boom"
+}
+
+func TestAs(t *testing.T) {
+	root := &MyError{}
+	err := fmt.Errorf("This is my custom error, %w", root)
+
+	errO := F.Pipe1(
+		err,
+		As[*MyError](),
+	)
+
+	assert.Equal(t, O.Of(root), errO)
+}
+
+func TestNotAs(t *testing.T) {
+	err := fmt.Errorf("This is my custom error")
+
+	errO := F.Pipe1(
+		err,
+		As[*MyError](),
+	)
+
+	assert.Equal(t, O.None[*MyError](), errO)
+}