tests: fix snippet tests in sandbox env (#2199)

Author: stephenplusplus

packages/google-cloud-node/src/index.js

@@ -161,6 +161,13 @@ Speech.detectEncoding_ = function(filename) {
  * @private
  */
 Speech.findFile_ = function(file, callback) {
+  if (global.GCLOUD_SANDBOX_ENV) {
+    callback(null, {
+      content: new Buffer('')
+    });
+    return;
+  }
+
   if (common.util.isCustomType(file, 'storage/file')) {
     // File is an instance of module:storage/file.
     callback(null, {

packages/google-cloud-node/test/index.js

@@ -211,6 +211,21 @@ describe('Speech', function() {
   });
 
   describe('findFile_', function() {
+    it('should return buffer for snippet sandbox', function(done) {
+      global.GCLOUD_SANDBOX_ENV = true;
+
+      Speech.findFile_({}, function(err, foundFile) {
+        delete global.GCLOUD_SANDBOX_ENV;
+        assert.ifError(err);
+
+        assert.deepEqual(foundFile, {
+          content: new Buffer('')
+        });
+
+        done();
+      });
+    });
+
     it('should convert a File object', function(done) {
       var file = {
         bucket: {