Add option to test.py to use desugared library from GitHub HEAD

Bug: 179896028
Change-Id: I7968308ae93398bc508ac1f9735d8a061287fd78
diff --git a/tools/test.py b/tools/test.py
index dffc4565..546a25f 100755
--- a/tools/test.py
+++ b/tools/test.py
@@ -16,6 +16,7 @@
 import time
 import uuid
 
+import archive_desugar_jdk_libs
 import gradle
 import notify
 import utils
@@ -161,6 +162,8 @@
       help='Enable Java debug agent and suspend compilation (default disabled)',
       default=False,
       action='store_true')
+  result.add_option('--desugared-library', '--desugared_library',
+      help='Build and use desugared library from GitHub.')
   return result.parse_args()
 
 def archive_failures():
@@ -178,6 +181,23 @@
   if utils.is_bot():
     gradle.RunGradle(['--no-daemon', 'clean'])
 
+  desugar_jdk_libs = None
+  if options.desugared_library:
+    if options.desugared_library != 'HEAD':
+      print("Only value supported for --desugared-library is 'HEAD'")
+      exit(1)
+    desugar_jdk_libs_dir = 'build/desugar_jdk_libs'
+    shutil.rmtree(desugar_jdk_libs_dir, ignore_errors=True)
+    os.makedirs(desugar_jdk_libs_dir)
+    print('Building desugared library.')
+    with utils.TempDir() as checkout_dir:
+      archive_desugar_jdk_libs.CloneDesugaredLibrary('google', checkout_dir)
+      (library_jar, maven_zip) = archive_desugar_jdk_libs.BuildDesugaredLibrary(checkout_dir)
+      desugar_jdk_libs = os.path.join(desugar_jdk_libs_dir, os.path.basename(library_jar))
+      shutil.copyfile(library_jar, desugar_jdk_libs)
+      print('Desugared library for test in ' + desugar_jdk_libs)
+
+
   gradle_args = ['--stacktrace']
   if utils.is_bot():
     # Bots don't like dangling processes.
@@ -261,6 +281,9 @@
     gradle_args.append('--no-daemon')
   if options.debug_agent:
     gradle_args.append('--no-daemon')
+  if desugar_jdk_libs:
+    gradle_args.append('-Pdesugar_jdk_libs=' + desugar_jdk_libs)
+
 
   # Build an R8 with dependencies for bootstrapping tests before adding test sources.
   gradle_args.append('r8WithDeps')