feat: add unwrap method to execution error and errors.

Signed-off-by: ghosind <ghosind@gmail.com>

Author: ghosind

error.go

@@ -59,6 +59,11 @@ func (e *executionError) Error() string {
 	return fmt.Sprintf("function %d error: %s", e.index, e.err.Error())
 }
 
+// Unwrap returns the inner error.
+func (e *executionError) Unwrap() error {
+	return e.err
+}
+
 // ExecutionErrors is an array of ExecutionError.
 type ExecutionErrors []ExecutionError
 
@@ -76,6 +81,15 @@ func (ee ExecutionErrors) Error() string {
 	return strings.TrimSpace(buf.String())
 }
 
+// Unwrap returns the execution errors.
+func (ee ExecutionErrors) Unwrap() []error {
+	errs := make([]error, 0, len(ee))
+	for _, e := range ee {
+		errs = append(errs, e)
+	}
+	return errs
+}
+
 // convertErrorListToExecutionErrors converts an array of the errors to the ExecutionErrors, it
 // will set the index as the execution error's index. If the error in the list is nil, it will skip
 // it and not add the error to the ExecutionErrors.

error_go120_test.go

@@ -0,0 +1,22 @@
+package async
+
+import (
+	"errors"
+	"testing"
+
+	"github.com/ghosind/go-assert"
+)
+
+func TestUnwrapExecutionsError(t *testing.T) {
+	a := assert.New(t)
+
+	innerErr := errors.New("expected error")
+	err := &executionError{
+		err:   innerErr,
+		index: 0,
+	}
+
+	errs := ExecutionErrors{err}
+	a.TrueNow(errors.Is(errs, err))
+	a.TrueNow(errors.Is(errs, innerErr))
+}

error_test.go

@@ -62,3 +62,16 @@ func TestConvertErrorListToExecutionErrors(t *testing.T) {
 		`function 0 error: expected error 1
 function 1 error: expected error 2`)
 }
+
+func TestUnwrapExecutionError(t *testing.T) {
+	a := assert.New(t)
+
+	innerErr := errors.New("expected error")
+	err := &executionError{
+		err:   innerErr,
+		index: 0,
+	}
+
+	a.TrueNow(errors.Is(err, innerErr))
+	a.NotTrueNow(errors.Is(err, errors.New("unexpected error")))
+}