backups: add setup/teardown

1. add setup, teardown hooks
2. move the managed mount setup and teardown to filesystem backend
3. remove this vague storage.js

we should convert storageApi into a real object, so we don't have to
keep passing apiConfig around

src/storage/s3.js

@@ -1,6 +1,14 @@
 'use strict';
 
 exports = module.exports = {
+    setup,
+    teardown,
+    cleanup,
+
+    testConfig,
+    removePrivateFields,
+    injectPrivateFields,
+
     getAvailableSize,
 
     upload,
@@ -13,12 +21,6 @@ exports = module.exports = {
     remove,
     removeDir,
 
-    cleanup,
-
-    testConfig,
-    removePrivateFields,
-    injectPrivateFields,
-
     // Used to mock AWS
     _chunk: chunk
 };
@@ -613,6 +615,14 @@ async function testConfig(apiConfig) {
     if (delError) throw new BoxError(BoxError.EXTERNAL_ERROR, `Error del object cloudron-testfile. ${formatError(delError)}`);
 }
 
+async function setup(apiConfig) {
+    assert.strictEqual(typeof apiConfig, 'object');
+}
+
+async function teardown(apiConfig) {
+    assert.strictEqual(typeof apiConfig, 'object');
+}
+
 function removePrivateFields(apiConfig) {
     apiConfig.secretAccessKey = constants.SECRET_PLACEHOLDER;
     return apiConfig;