Build API: Add UnitTest endpoint.

BUG=chromium:905030, b:130745732
TEST=manual, run_tests
CQ-DEPEND=CL:1577651

Change-Id: I420bb6a202cea2301e94aef440edf0330eaf617b
Reviewed-on: https://chromium-review.googlesource.com/1576063
Commit-Ready: Alex Klein <saklein@chromium.org>
Tested-by: Alex Klein <saklein@chromium.org>
Reviewed-by: Evan Hernandez <evanhernandez@chromium.org>
diff --git a/api/controller/test.py b/api/controller/test.py
index 04b1aaf..d38e10d 100644
--- a/api/controller/test.py
+++ b/api/controller/test.py
@@ -10,7 +10,15 @@
 
 from __future__ import print_function
 
+import os
+
+from chromite.api.controller import controller_util
+from chromite.cbuildbot import commands
+from chromite.lib import constants
 from chromite.lib import cros_build_lib
+from chromite.lib import failures_lib
+from chromite.lib import osutils
+from chromite.lib import portage_util
 from chromite.lib import sysroot_lib
 from chromite.service import test
 
@@ -33,3 +41,76 @@
     cros_build_lib.Die('The provided sysroot does not exist.')
 
   return 0 if test.DebugInfoTest(sysroot_path) else 1
+
+
+def BuildTargetUnitTest(input_proto, output_proto):
+  """Run a build target's ebuild unit tests."""
+  # Required args.
+  board = input_proto.build_target.name
+  result_path = input_proto.result_path
+
+  if not board:
+    cros_build_lib.Die('build_target.name is required.')
+  if not result_path:
+    cros_build_lib.Die('result_path is required.')
+
+  # Chroot handling.
+  chroot = input_proto.chroot.path
+  cache_dir = input_proto.chroot.cache_dir
+
+  chroot_args = []
+  if chroot:
+    chroot_args.extend(['--chroot', chroot])
+  else:
+    chroot = constants.DEFAULT_CHROOT_PATH
+
+  if cache_dir:
+    chroot_args.extend(['--cache_dir', cache_dir])
+
+  # TODO(crbug.com/954609) Service implementation.
+  extra_env = {'USE': 'chrome_internal'}
+  base_dir = os.path.join(chroot, 'tmp')
+  # The called code also sets the status file in some cases, but the hacky
+  # call makes it not always work, so set up our own just in case.
+  with osutils.TempDir(base_dir=base_dir) as tempdir:
+    full_sf_path = os.path.join(tempdir, 'status_file')
+    chroot_sf_path = full_sf_path.replace(chroot, '')
+    extra_env[constants.PARALLEL_EMERGE_STATUS_FILE_ENVVAR] = chroot_sf_path
+
+    try:
+      commands.RunUnitTests(constants.SOURCE_ROOT, board, extra_env=extra_env,
+                            chroot_args=chroot_args)
+    except failures_lib.PackageBuildFailure as e:
+      # Add the failed packages.
+      for pkg in e.failed_packages:
+        cpv = portage_util.SplitCPV(pkg, strict=False)
+        package_info = output_proto.failed_packages.add()
+        controller_util.CPVToPackageInfo(cpv, package_info)
+
+      return 1
+    except failures_lib.BuildScriptFailure:
+      # Check our status file for failed packages in case the calling code's
+      # file didn't get set.
+      for cpv in portage_util.ParseParallelEmergeStatusFile(full_sf_path):
+        package_info = output_proto.failed_packages.add()
+        controller_util.CPVToPackageInfo(cpv, package_info)
+
+      return 1
+
+    tarball = _BuildUnittestTarball(chroot, board, result_path)
+    if tarball:
+      output_proto.tarball_path = tarball
+
+
+def _BuildUnittestTarball(chroot, board, result_path):
+  """Build the unittest tarball."""
+  tarball = 'unit_tests.tar'
+  tarball_path = os.path.join(result_path, tarball)
+
+  cwd = os.path.join(chroot, 'build', board, constants.UNITTEST_PKG_PATH)
+
+  result = cros_build_lib.CreateTarball(tarball_path, cwd, chroot=chroot,
+                                        compression=cros_build_lib.COMP_NONE,
+                                        error_code_ok=True)
+
+  return tarball_path if result.returncode == 0 else None