testhelper: Open-code check for process's error codes

While the "command" package provides a nice helper to check for
process's error codes, use of the "command" package in the testhelper
keeps us from using leak checkers in the "command" package itself.

Open-code this function in the testhelper package to reduce dependencies
to the "command" package.

1 files changed, 6 insertions, 2 deletions

diff --git a/internal/testhelper/leakage.go b/internal/testhelper/leakage.go
index 6afb1f94d..d20843580 100644
--- a/internal/testhelper/leakage.go
+++ b/internal/testhelper/leakage.go
@@ -61,8 +61,12 @@ func mustFindNoRunningChildProcess() error {
 		return fmt.Errorf("found running child processes %s:\n%s", pidsComma, psOut)
 	}
 
-	if status, ok := command.ExitStatus(err); ok && status == 1 {
-		// Exit status 1 means no processes were found
+	exitError, ok := err.(*exec.ExitError)
+	if !ok {
+		return fmt.Errorf("expected ExitError, got %T", err)
+	}
+
+	if exitError.ExitCode() == 1 {
 		return nil
 	}