Add backups.testProviderConfig

fields like format/retention won't be validated here since it's only
testing the access credentials

src/apps.js

@@ -1463,7 +1463,7 @@ function importApp(appId, data, auditSource, callback) {
         if (error) return callback(error);
 
         // TODO: make this smarter to do a read-only test and check if the file exists in the storage backend
-        const testBackupConfig = backupConfig ? backups.testConfig.bind(null, backupConfig) : (next) => next();
+        const testBackupConfig = backupConfig ? backups.testProviderConfig.bind(null, backupConfig) : (next) => next();
 
         testBackupConfig(function (error) {
             if (error) return callback(error);

src/backups.js

@@ -2,6 +2,7 @@
 
 exports = module.exports = {
     testConfig: testConfig,
+    testProviderConfig: testProviderConfig,
 
     getByStatePaged: getByStatePaged,
     getByAppIdPaged: getByAppIdPaged,
@@ -118,6 +119,17 @@ function testConfig(backupConfig, callback) {
     api(backupConfig.provider).testConfig(backupConfig, callback);
 }
 
+
+function testProviderConfig(backupConfig, callback) {
+    assert.strictEqual(typeof backupConfig, 'object');
+    assert.strictEqual(typeof callback, 'function');
+
+    var func = api(backupConfig.provider);
+    if (!func) return callback(new BoxError(BoxError.BAD_FIELD, 'unknown storage provider', { field: 'provider' }));
+
+    api(backupConfig.provider).testConfig(backupConfig, callback);
+}
+
 function getByStatePaged(state, page, perPage, callback) {
     assert.strictEqual(typeof state, 'string');
     assert(typeof page === 'number' && page > 0);

src/routes/apps.js

@@ -406,7 +406,6 @@ function importApp(req, res, next) {
         if (req.body.backupConfig) {
             if (typeof backupConfig.provider !== 'string') return next(new HttpError(400, 'provider is required'));
             if ('key' in backupConfig && typeof backupConfig.key !== 'string') return next(new HttpError(400, 'key must be a string'));
-            if (typeof backupConfig.format !== 'string') return next(new HttpError(400, 'format must be a string'));
             if ('acceptSelfSignedCerts' in backupConfig && typeof backupConfig.acceptSelfSignedCerts !== 'boolean') return next(new HttpError(400, 'format must be a boolean'));
 
             // testing backup config can take sometime