BuildAPI: Unit test cleanup / additions

BUG=none
TEST=manual,run_tests

Change-Id: I6c2056531bd1ea0f9209264edbf9295671f31697
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/chromite/+/1987853
Tested-by: Michael Mortensen <mmortensen@google.com>
Reviewed-by: Alex Klein <saklein@chromium.org>
Commit-Queue: Michael Mortensen <mmortensen@google.com>
diff --git a/api/controller/toolchain_unittest.py b/api/controller/toolchain_unittest.py
index b2801c5..675b646 100644
--- a/api/controller/toolchain_unittest.py
+++ b/api/controller/toolchain_unittest.py
@@ -217,3 +217,11 @@
     request = self._GetRequest([BuilderConfig.Artifacts.IMAGE_ARCHIVES])
     toolchain.BundleArtifacts(request, self.response, self.api_config)
     self.assertEqual([], list(self.response.artifacts_info))
+
+  def testValidateOnly(self):
+    """Sanity check that a validate only call does not execute any logic."""
+    patch = self.PatchObject(toolchain_util, 'BundleArtifacts')
+    request = self._GetRequest([BuilderConfig.Artifacts.IMAGE_ARCHIVES])
+    toolchain.BundleArtifacts(request, self.response,
+                              self.validate_only_config)
+    patch.assert_not_called()