Add test for SIGCHLD coalescing.

tests/issue-122-coalesced-sigchld.d

@@ -0,0 +1,76 @@
+#!/usr/bin/env dub
+/+ dub.sdl:
+	name "test"
+	dependency "eventcore" path=".."
++/
+
+module test;
+
+import core.time : Duration, msecs;
+import eventcore.core;
+import std.process : thisProcessID;
+import std.stdio;
+
+version (Windows) {
+	void main()
+	{
+		writefln("Skipping SIGCHLD coalesce test on Windows.");
+	}
+} else:
+
+import core.sys.posix.sys.wait : waitpid, WNOHANG;
+
+int numProc;
+
+void main(string[] args)
+{
+	// child mode
+	if (args.length == 2)
+	{
+		import core.thread : Thread;
+		writeln("Child: ", args[1], " from ", thisProcessID);
+		Thread.sleep((Clock.currStdTime - args[1].to!long).hnsecs);
+		return;
+	}
+
+	auto tm = eventDriver.timers.create();
+	eventDriver.timers.set(tm, 5.seconds, 0.msecs);
+	eventDriver.timers.wait(tm, (tm) @trusted {
+		assert(false, "Test hung.");
+	});
+
+	// attempt to let all child processes finish in exactly 1 second to force
+	// signal coalescing
+	auto targettime = Clock.currTime(UTC()) + 1.seconds;
+
+	auto procs = new ProcessID[](20);
+	foreach (i, ref p; procs) {
+		p = eventDriver.processes.spawn(
+			["./test", targettime.stdTime.to!string],
+			ProcessStdinFile(ProcessRedirect.inherit),
+			ProcessStdoutFile(ProcessRedirect.inherit),
+			ProcessStderrFile(ProcessRedirect.inherit),
+			null, ProcessConfig.none, null
+		);
+		assert(p != Process.init);
+
+		writeln("Started child: ", p.pid);
+		numProc++;
+	}
+
+	foreach (p; procs) {
+		auto wres = eventDriver.processes.wait(p.pid, (ProcessID pid, int res) nothrow
+		{
+			numProc--;
+			try writefln("Child %s exited with %s", pid, res);
+			catch(Exception){}
+		});
+
+		if (wres == 0) numProc--;
+	}
+
+	do eventDriver.core.processEvents(Duration.max);
+	while (numProc);
+
+	foreach (p; procs) assert(waitpid(cast(int)p, null, WNOHANG) == -1);
+}