BuildAPI: Add unit tests and mocks for Toolchain Service.

Also fix a few test cases in UploadVettedFDOArtifactsTest that called
UploadEbuildWithAFDOArtifacts by mistake.

BUG=chromium:1000856
TEST=run_tests

Change-Id: I8dc934301bd344ee9f725273161f0fc56c64f4ef
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/chromite/+/1929891
Reviewed-by: Alex Klein <saklein@chromium.org>
Commit-Queue: Michael Mortensen <mmortensen@google.com>
Tested-by: Michael Mortensen <mmortensen@google.com>
diff --git a/api/controller/toolchain.py b/api/controller/toolchain.py
index faf3646..e123403 100644
--- a/api/controller/toolchain.py
+++ b/api/controller/toolchain.py
@@ -28,7 +28,13 @@
   }[artifact_type]
 
 
-@faux.all_empty
+def _UpdateEbuildWithAFDOArtifactsResponse(_input_proto, output_proto, _config):
+  """Add successful status to the faux response."""
+  output_proto.status = True
+
+
+@faux.success(_UpdateEbuildWithAFDOArtifactsResponse)
+@faux.empty_error
 @validate.require('build_target.name')
 @validate.is_in('artifact_type', _NAMES_FOR_ARTIFACTS)
 @validate.validation_complete
@@ -40,13 +46,18 @@
     output_proto (VerifyAFDOArtifactsResponse): The output proto
     _config (api_config.ApiConfig): The API call config.
   """
-
   board = input_proto.build_target.name
   update_method = _GetMethodForUpdatingArtifacts(input_proto.artifact_type)
   output_proto.status = update_method(board)
 
 
-@faux.all_empty
+def _UploadVettedAFDOArtifactsResponse(_input_proto, output_proto, _config):
+  """Add successful status to the faux response."""
+  output_proto.status = True
+
+
+@faux.success(_UploadVettedAFDOArtifactsResponse)
+@faux.empty_error
 @validate.require('build_target.name')
 @validate.is_in('artifact_type', _NAMES_FOR_ARTIFACTS)
 @validate.validation_complete