binary search tool: Make 1st resumed iteration non-incremental

If resuming a bisection, we want to make sure all current good items are
switched to good and all current bad items are switched to bad. This is
so the bisection tool will resume in a known, stable state. Incremental
builds are essentially diffs from previous builds, and the base
environment may have changed since the last execution.

TEST=Add test code, run unit tests

Change-Id: I9ac855efbcfb48bc86f245f33ee29d0c38aa7af9
Reviewed-on: https://chrome-internal-review.googlesource.com/274175
Commit-Ready: Cassidy Burden <cburden@google.com>
Tested-by: Cassidy Burden <cburden@google.com>
Reviewed-by: Caroline Tice <cmtice@google.com>

2 files changed, 15 insertions, 0 deletions

diff --git a/binary_search_tool/binary_search_state.py b/binary_search_tool/binary_search_state.py
index f0415667..f78e768c 100755
--- a/binary_search_tool/binary_search_state.py
+++ b/binary_search_tool/binary_search_state.py
@@ -370,7 +370,18 @@ class BinarySearchState(object):
       bss.ce = command_executer.GetCommandExecuter()
       bss.binary_search.logger = bss.l
       bss.start_time = time.time()
+
+      # Set resumed to be True so we can enter DoBinarySearch without the method
+      # resetting our current search_cycles to 0.
       bss.resumed = True
+
+      # Set currently_good_items and currently_bad_items to empty so that the
+      # first iteration after resuming will always be non-incremental. This is
+      # just in case the environment changes, the user makes manual changes, or
+      # a previous switch_script corrupted the environment.
+      bss.currently_good_items = set([])
+      bss.currently_bad_items = set([])
+
       binary_search_perforce.verbose = bss.verbose
       return bss
     except StandardError:
diff --git a/binary_search_tool/test/binary_search_tool_tester.py b/binary_search_tool/test/binary_search_tool_tester.py
index 12013d32..ddf302b0 100755
--- a/binary_search_tool/test/binary_search_tool_tester.py
+++ b/binary_search_tool/test/binary_search_tool_tester.py
@@ -227,12 +227,16 @@ class BisectingUtilsTest(unittest.TestCase):
 
     bss = binary_search_state.MockBinarySearchState()
     bss.all_items = test_items
+    bss.currently_good_items = set([1, 2, 3])
+    bss.currently_bad_items = set([4, 5])
     bss.SaveState()
 
     bss = None
 
     bss2 = binary_search_state.MockBinarySearchState.LoadState()
     self.assertEquals(bss2.all_items, test_items)
+    self.assertEquals(bss2.currently_good_items, set([]))
+    self.assertEquals(bss2.currently_bad_items, set([]))
 
   def test_tmp_cleanup(self):
     bss = binary_search_state.MockBinarySearchState(