Add partial-cpus test

test/emu/ovni/CMakeLists.txt

@@ -11,6 +11,7 @@ test_emu(sort-first-and-full-ring.c SORT
   SHOULD_FAIL REGEX "cannot find a event previous to clock")
 test_emu(burst-stats.c REGEX "burst stats: median/avg/max =  33/ 33/ 33 ns")
 test_emu(mp-simple.c MP)
+test_emu(partial-cpus.c MP)
 test_emu(merge-cpus-loom.c MP)
 test_emu(version-good.c)
 test_emu(version-bad.c SHOULD_FAIL REGEX "incompatible .* version")

test/emu/ovni/partial-cpus.c

@@ -0,0 +1,34 @@
+/* Copyright (c) 2024 Barcelona Supercomputing Center (BSC)
+ * SPDX-License-Identifier: GPL-3.0-or-later */
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <unistd.h>
+#include "common.h"
+#include "compat.h"
+#include "instr.h"
+#include "ovni.h"
+
+/* Ensures that we can emit a partial list of CPUs. */
+int
+main(void)
+{
+	int rank = atoi(getenv("OVNI_RANK"));
+	int nranks = atoi(getenv("OVNI_NRANKS"));
+
+	if (nranks < 2)
+		die("needs at least 2 ranks");
+
+	ovni_proc_init(1, "loom0", getpid());
+	ovni_thread_init(get_tid());
+
+	int i = rank;
+
+	/* Only emit one CPU per thread */
+	ovni_add_cpu(i, i);
+
+	instr_thread_execute(i, -1, 0);
+	instr_end();
+
+	return 0;
+}