errors: Use `errors.As()` for type assertion

Currently for type assertion of errors, we use the `err.(<Interface>)`
form. This works, but is not compatible with wrapped errors. So let's
use `errors.As()` instead.

1 files changed, 4 insertions, 2 deletions

diff --git a/cmd/gitaly/main_test.go b/cmd/gitaly/main_test.go
index b649c10aa..339d7cbd6 100644
--- a/cmd/gitaly/main_test.go
+++ b/cmd/gitaly/main_test.go
@@ -2,6 +2,7 @@ package main
 
 import (
 	"bytes"
+	"errors"
 	"os/exec"
 	"testing"
 
@@ -63,8 +64,9 @@ func TestGitalyCLI(t *testing.T) {
 			err := cmd.Run()
 
 			exitCode := 0
-			if err != nil {
-				exitCode = err.(*exec.ExitError).ExitCode()
+			var exitErr *exec.ExitError
+			if errors.As(err, &exitErr) {
+				exitCode = exitErr.ExitCode()
 			}
 
 			assert.Equal(t, tc.exitCode, exitCode)