Add --reset-to-deps and improve comments

tests/gclient_scm_test.py

Index: tests/gclient_scm_test.py
diff --git a/tests/gclient_scm_test.py b/tests/gclient_scm_test.py
index fb2ea42e70f6303f6cac3d90054b699e25aab35a..20a4cbdb08263a0caedb33d8ffdfb7c84c589edd 100755
--- a/tests/gclient_scm_test.py
+++ b/tests/gclient_scm_test.py
@@ -527,10 +527,12 @@ from :3
       return
     options = self.Options()
     file_path = gclient_scm.os.path.join(self.base_path, 'a')
-    gclient_scm.os.remove(file_path)
     scm = gclient_scm.CreateSCM(url=self.url, root_dir=self.root_dir,
                                 relpath=self.relpath)
     file_list = []
+    scm.update(options, None, file_list)
+    gclient_scm.os.remove(file_path)
+    file_list = []
     scm.revert(options, self.args, file_list)
     self.assertEquals(file_list, [file_path])
     file_list = []
@@ -544,41 +546,47 @@ from :3
     scm = gclient_scm.CreateSCM(url=self.url, root_dir=self.root_dir,
                                 relpath=self.relpath)
     file_list = []
+    scm.update(options, None, file_list)
+    file_list = []
     scm.revert(options, self.args, file_list)
     self.assertEquals(file_list, [])
     self.assertEquals(scm.revinfo(options, self.args, None),
-                      '069c602044c5388d2d15c3f875b057c852003458')
+                      'a7142dc9f0009350b96a11f372b6ea658592aa95')
 
 
   def testRevertModified(self):
     if not self.enabled:
       return
     options = self.Options()
-    file_path = gclient_scm.os.path.join(self.base_path, 'a')
-    open(file_path, 'a').writelines('touched\n')
     scm = gclient_scm.CreateSCM(url=self.url, root_dir=self.root_dir,
                                 relpath=self.relpath)
     file_list = []
+    scm.update(options, None, file_list)
+    file_path = gclient_scm.os.path.join(self.base_path, 'a')
+    open(file_path, 'a').writelines('touched\n')
+    file_list = []
     scm.revert(options, self.args, file_list)
     self.assertEquals(file_list, [file_path])
     file_list = []
     scm.diff(options, self.args, file_list)
     self.assertEquals(file_list, [])
     self.assertEquals(scm.revinfo(options, self.args, None),
-                      '069c602044c5388d2d15c3f875b057c852003458')
+                      'a7142dc9f0009350b96a11f372b6ea658592aa95')
 
   def testRevertNew(self):
     if not self.enabled:
       return
     options = self.Options()
+    scm = gclient_scm.CreateSCM(url=self.url, root_dir=self.root_dir,
+                                relpath=self.relpath)
+    file_list = []
+    scm.update(options, None, file_list)
     file_path = gclient_scm.os.path.join(self.base_path, 'c')
     f = open(file_path, 'w')
     f.writelines('new\n')
     f.close()
     Popen(['git', 'add', 'c'], stdout=PIPE,
           stderr=STDOUT, cwd=self.base_path).communicate()
-    scm = gclient_scm.CreateSCM(url=self.url, root_dir=self.root_dir,
-                                relpath=self.relpath)
     file_list = []
     scm.revert(options, self.args, file_list)
     self.assertEquals(file_list, [file_path])
@@ -586,7 +594,7 @@ from :3
     scm.diff(options, self.args, file_list)
     self.assertEquals(file_list, [])
     self.assertEquals(scm.revinfo(options, self.args, None),
-                      '069c602044c5388d2d15c3f875b057c852003458')
+                      'a7142dc9f0009350b96a11f372b6ea658592aa95')
 
   def testStatusNew(self):
     if not self.enabled: