Ensure all IO errors are handled in the StaticCertManager test

internal/server/cert_test.go

@@ -3,6 +3,7 @@ package server
 import (
 	"crypto/tls"
 	"os"
+	"path"
 	"testing"
 
 	"github.com/stretchr/testify/require"
@@ -42,7 +43,8 @@ func TestCertificateLoadingRaceCondition(t *testing.T) {
 
 	manager := NewStaticCertManager(certPath, keyPath)
 	go func() {
-		manager.GetCertificate(&tls.ClientHelloInfo{})
+		_, err2 := manager.GetCertificate(&tls.ClientHelloInfo{})
+		require.NoError(t, err2)
 	}()
 	cert, err := manager.GetCertificate(&tls.ClientHelloInfo{})
 	require.NoError(t, err)
@@ -58,8 +60,8 @@ func TestCachesLoadedCertificate(t *testing.T) {
 	require.NoError(t, err)
 	require.NotNil(t, cert1)
 
-	os.Remove(certPath)
-	os.Remove(keyPath)
+	require.Nil(t, os.Remove(certPath))
+	require.Nil(t, os.Remove(keyPath))
 
 	cert2, err := manager.GetCertificate(&tls.ClientHelloInfo{})
 	require.Equal(t, cert1, cert2)
@@ -85,21 +87,19 @@ func TestErrorWhenKeyFormatIsInvalid(t *testing.T) {
 func prepareTestCertificateFiles(t *testing.T) (string, string, error) {
 	t.Helper()
 
-	certFile, err := os.CreateTemp("", "example-cert-*.pem")
+	dir := t.TempDir()
+	certFile := path.Join(dir, "example-cert.pem")
+	keyFile := path.Join(dir, "example-key.pem")
+
+	err := os.WriteFile(certFile, []byte(certPem), 0644)
 	if err != nil {
 		return "", "", err
 	}
-	defer certFile.Close()
-	certFile.Write([]byte(certPem))
-	t.Cleanup(func() { os.Remove(certFile.Name()) })
 
-	keyFile, err := os.CreateTemp("", "example-key-*.pem")
+	err = os.WriteFile(keyFile, []byte(keyPem), 0644)
 	if err != nil {
 		return "", "", err
 	}
-	defer keyFile.Close()
-	keyFile.Write([]byte(keyPem))
-	t.Cleanup(func() { os.Remove(keyFile.Name()) })
 
-	return certFile.Name(), keyFile.Name(), nil
+	return certFile, keyFile, nil
 }