From e3092aadc71d481695597b59c8c6609cb035ef7a Mon Sep 17 00:00:00 2001
From: Thomas Nagy <tnagy@waf.io>
Date: Thu, 1 Sep 2016 22:08:03 +0200
Subject: [PATCH] Parallel tests can now have an execution order

---
 demos/c/wscript          |  6 ++++++
 waflib/Tools/c_config.py | 25 +++++++++++++++++++++++++
 2 files changed, 31 insertions(+)

diff --git a/demos/c/wscript b/demos/c/wscript
index 43878786..b09e54ed 100644
--- a/demos/c/wscript
+++ b/demos/c/wscript
@@ -42,10 +42,16 @@ def configure(conf):
 		#ctx.check_large_file(mandatory=False)
 
 	conf.multicheck(
+		# list of conf.check() arguments
 		{'header_name':'stdio.h', 'msg':'... stdio', 'uselib_store': 'STDIO'},
 		{'header_name':'xyztabcd.h', 'msg':'... optional xyztabcd.h', 'mandatory': False},
 		{'header_name':'stdlib.h', 'msg':'... stdlib', 'okmsg': 'aye', 'errmsg': 'nope'},
 		{'func': test_build, 'msg':'... testing an arbitrary build function', 'okmsg':'ok'},
+
+		# parallelism control with after_tests/before_tests
+		{'header_name':'malloc.h', 'msg':'... malloc', 'uselib_store': 'MALLOC', 'id': 'malloc_t'},
+		{'header_name':'unistd.h', 'msg':'... unistd', 'uselib_store': 'UNISTD', 'before_tests': ['malloc_t']},
+
 		msg       = 'Checking for headers in parallel',
 		#mandatory = False, # set to False to make all tests non-mandatory
 		#run_all_tests = False # set to False to stop at the first error
diff --git a/waflib/Tools/c_config.py b/waflib/Tools/c_config.py
index 88d4774e..fa298622 100644
--- a/waflib/Tools/c_config.py
+++ b/waflib/Tools/c_config.py
@@ -1250,10 +1250,17 @@ class cfgtask(Task.TaskBase):
 
 	Make sure to use locks if concurrent access to the same conf.env data is necessary.
 	"""
+	def __init__(self, *k, **kw):
+		Task.TaskBase.__init__(self, *k, **kw)
+		self.run_after = set()
+
 	def display(self):
 		return ''
 
 	def runnable_status(self):
+		for x in self.run_after:
+			if not x.hasrun:
+				return Task.ASK_LATER
 		return Task.RUN_ME
 
 	def uid(self):
@@ -1343,6 +1350,8 @@ def multicheck(self, *k, **kw):
 	bld = par()
 	bld.keep = kw.get('run_all_tests', True)
 	tasks = []
+
+	id_to_task = {}
 	for dct in k:
 		x = Task.classes['cfgtask'](bld=bld)
 		tasks.append(x)
@@ -1354,6 +1363,22 @@ def multicheck(self, *k, **kw):
 		# bind a logger that will keep the info in memory
 		x.logger = Logs.make_mem_logger(str(id(x)), self.logger)
 
+		if 'id' in dct:
+			id_to_task[dct['id']] = x
+
+	# second pass to set dependencies with after_test/before_test
+	for x in tasks:
+		for key in Utils.to_list(x.args.get('before_tests', [])):
+			tsk = id_to_task[key]
+			if not tsk:
+				raise ValueError('No test named %r' % key)
+			tsk.run_after.add(x)
+		for key in Utils.to_list(x.args.get('after_tests', [])):
+			tsk = id_to_task[key]
+			if not tsk:
+				raise ValueError('No test named %r' % key)
+			x.run_after.add(tsk)
+
 	def it():
 		yield tasks
 		while 1: