Add the steering stage of the framework.

BUG=None
TEST=unit testings for the pipeline stage, pipeline workers, generation and
steering.

Change-Id: Id92bcf04ee24dfbc918f59ac8d87d30ee69e47b3
Reviewed-on: https://gerrit-int.chromium.org/41454
Reviewed-by: Simon Que <sque@google.com>
Reviewed-by: Luis Lozano <llozano@chromium.org>
Commit-Queue: Yuheng Long <yuhenglong@google.com>
Tested-by: Yuheng Long <yuhenglong@google.com>

1 files changed, 16 insertions, 9 deletions

diff --git a/bestflags/generation.py b/bestflags/generation.py
index f1a63631..7f0e94a1 100644
--- a/bestflags/generation.py
+++ b/bestflags/generation.py
@@ -85,19 +85,26 @@ class Generation(object):
 
     Args:
       task: A task that has its results ready.
+
+    Returns:
+      Whether the input task belongs to this generation.
     """
 
-    # If there is a match.
-    if task in self._exe_pool:
-      # Remove the place holder task in this generation and store the new input
-      # task and its result.
-      self._exe_pool.remove(task)
-      self._exe_pool.add(task)
+    # If there is a match, the input task belongs to this generation.
+    if task not in self._exe_pool:
+      return False
+
+    # Remove the place holder task in this generation and store the new input
+    # task and its result.
+    self._exe_pool.remove(task)
+    self._exe_pool.add(task)
+
+    # The current generation will have one less task to wait on.
+    self._pending -= 1
 
-      # The current generation will have one less task to wait on.
-      self._pending -= 1
+    assert self._pending >= 0
 
-      assert self._pending >= 0
+    return True
 
   def Improve(self):
     """True if this generation has improvement over its parent generation.