Build API: Adding mock responses.

Complete mock responses for the api, sdk, and sysroot controllers.
Added empty mock responses for the rest of the endpoints, and bugs
have been created to complete them.

BUG=chromium:999178
TEST=run_tests

Change-Id: Ib9ead797a588a9f4ccf50a6a663ab7dbdf5d0ae8
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/chromite/+/1787937
Reviewed-by: Michael Mortensen <mmortensen@google.com>
Tested-by: Alex Klein <saklein@chromium.org>
Commit-Queue: Alex Klein <saklein@chromium.org>
diff --git a/api/controller/sdk_unittest.py b/api/controller/sdk_unittest.py
index 1b534f6..cd710d2 100644
--- a/api/controller/sdk_unittest.py
+++ b/api/controller/sdk_unittest.py
@@ -49,6 +49,16 @@
                           self.validate_only_config)
     patch.assert_not_called()
 
+  def testMockCall(self):
+    """Sanity check that a validate only call does not execute any logic."""
+    patch = self.PatchObject(sdk_service, 'Create')
+
+    rc = sdk_controller.Create(self._GetRequest(), self.response,
+                               self.mock_call_config)
+    patch.assert_not_called()
+    self.assertFalse(rc)
+    self.assertTrue(self.response.version.version)
+
   def testSuccess(self):
     """Test the successful call output handling."""
     self.PatchObject(sdk_service, 'Create', return_value=1)
@@ -60,7 +70,7 @@
     self.assertEqual(1, self.response.version.version)
 
   def testFalseArguments(self):
-    """Test the argument handling."""
+    """Test False argument handling."""
     # Create the patches.
     self.PatchObject(sdk_service, 'Create', return_value=1)
     args_patch = self.PatchObject(sdk_service, 'CreateArguments')
@@ -74,6 +84,7 @@
                                   use_image=True, paths=mock.ANY)
 
   def testTrueArguments(self):
+    """Test True arguments handling."""
     # Create the patches.
     self.PatchObject(sdk_service, 'Create', return_value=1)
     args_patch = self.PatchObject(sdk_service, 'CreateArguments')
@@ -86,6 +97,7 @@
                                   use_image=False, paths=mock.ANY)
 
   def testPathArguments(self):
+    """Test the path arguments handling."""
     # Create the patches.
     self.PatchObject(sdk_service, 'Create', return_value=1)
     paths_patch = self.PatchObject(sdk_service, 'ChrootPaths')
@@ -127,6 +139,16 @@
                           self.validate_only_config)
     patch.assert_not_called()
 
+  def testMockCall(self):
+    """Sanity check that a validate only call does not execute any logic."""
+    patch = self.PatchObject(sdk_service, 'Update')
+
+    rc = sdk_controller.Create(self._GetRequest(), self.response,
+                               self.mock_call_config)
+    patch.assert_not_called()
+    self.assertFalse(rc)
+    self.assertTrue(self.response.version.version)
+
   def testSuccess(self):
     """Successful call output handling test."""
     expected_version = 1