diff --git a/letsencrypt-nginx/letsencrypt_nginx/tests/util.py b/letsencrypt-nginx/letsencrypt_nginx/tests/util.py
index cb4e08ddf..e60feb3d3 100644
--- a/letsencrypt-nginx/letsencrypt_nginx/tests/util.py
+++ b/letsencrypt-nginx/letsencrypt_nginx/tests/util.py
@@ -49,21 +49,25 @@ def get_nginx_configurator(
 
     backups = os.path.join(work_dir, "backups")
 
-    config = configurator.NginxConfigurator(
-        config=mock.MagicMock(
-            nginx_server_root=config_path,
-            le_vhost_ext="-le-ssl.conf",
-            config_dir=config_dir,
-            work_dir=work_dir,
-            backup_dir=backups,
-            temp_checkpoint_dir=os.path.join(work_dir, "temp_checkpoints"),
-            in_progress_dir=os.path.join(backups, "IN_PROGRESS"),
-            server="https://acme-server.org:443/new",
-            tls_sni_01_port=5001,
-        ),
-        name="nginx",
-        version=version)
-    config.prepare()
+    with mock.patch("letsencrypt_nginx.configurator.le_util."
+            "exe_exists") as mock_exe_exists:
+        mock_exe_exists.return_value = True
+
+        config = configurator.NginxConfigurator(
+            config=mock.MagicMock(
+                nginx_server_root=config_path,
+                le_vhost_ext="-le-ssl.conf",
+                config_dir=config_dir,
+                work_dir=work_dir,
+                backup_dir=backups,
+                temp_checkpoint_dir=os.path.join(work_dir, "temp_checkpoints"),
+                in_progress_dir=os.path.join(backups, "IN_PROGRESS"),
+                server="https://acme-server.org:443/new",
+                tls_sni_01_port=5001,
+            ),
+            name="nginx",
+            version=version)
+        config.prepare()
 
     # Provide general config utility.
     nsconfig = configuration.NamespaceConfig(config.config)