getdeps: improve how run_cmake.py invokes ctest

Summary:
Update the generated `run_cmake.py` script to tell ctest to print the test
output on failure.  Also pass in a `-j` flag to run tests in parallel by
default.

These flags are already passed in by default when running `getdeps.py test`;
this simply updates this developer utility script to do the same.

Reviewed By: wez

Differential Revision: D21307806

fbshipit-source-id: 42045b0f9362494042c79bc946a1004ff8ad98b6

build/fbcode_builder/getdeps/builder.py

@@ -244,6 +244,17 @@ CMAKE_ENV = {env_str}
 CMAKE_DEFINE_ARGS = {define_args_str}
 
 
+def get_jobs_argument(num_jobs_arg: int) -> str:
+    if num_jobs_arg > 0:
+        return "-j" + str(num_jobs_arg)
+
+    import multiprocessing
+    num_jobs = multiprocessing.cpu_count()
+    if sys.platform == "win32":
+        num_jobs //= 2
+    return "-j" + str(num_jobs)
+
+
 def main():
     ap = argparse.ArgumentParser()
     ap.add_argument(
@@ -266,6 +277,14 @@ def main():
       dest="mode",
       help="An alias for --mode=build",
     )
+    ap.add_argument(
+      "-j",
+      "--num-jobs",
+      action="store",
+      type=int,
+      default=0,
+      help="Run the build or tests with the specified number of parallel jobs",
+    )
     ap.add_argument(
       "--install",
       action="store_const",
@@ -300,9 +319,14 @@ def main():
                 target,
                 "--config",
                 "Release",
+                get_jobs_argument(args.num_jobs),
         ] + args.cmake_args
     elif args.mode == "test":
-        full_cmd = CMD_PREFIX + [{dev_run_script}CTEST] + args.cmake_args
+        full_cmd = CMD_PREFIX + [
+            {dev_run_script}CTEST,
+            "--output-on-failure",
+            get_jobs_argument(args.num_jobs),
+        ] + args.cmake_args
     else:
         ap.error("unknown invocation mode: %s" % (args.mode,))