Add a test for executeAndWait

---
Signed-off-by: Michael Ferguson <[email protected]>

compiler/dyno/test/util/CMakeLists.txt

@@ -15,7 +15,8 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
-comp_unit_test(testQuoteStrings)
-comp_unit_test(testQueryTimingAndTrace)
 comp_unit_test(testIteratorAdapters)
 comp_unit_test(testLLVMsupport)
+comp_unit_test(testQueryTimingAndTrace)
+comp_unit_test(testQuoteStrings)
+comp_unit_test(testSubprocess)

compiler/dyno/test/util/testSubprocess.cpp

@@ -0,0 +1,77 @@
+/*
+ * Copyright 2021-2022 Hewlett Packard Enterprise Development LP
+ * Other additional copyright holders may be indicated within.
+ *
+ * The entirety of this work is licensed under the Apache License,
+ * Version 2.0 (the "License"); you may not use this file except
+ * in compliance with the License.
+ *
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#include "chpl/util/subprocess.h"
+
+#include <cassert>
+
+// always check assertions in this test
+#ifdef NDEBUG
+#undef NDEBUG
+#endif
+
+using namespace chpl;
+
+// check that trying to run a nonexistant command returns an error
+static void checkNonexistent() {
+  int rc;
+  std::vector<std::string> cmd;
+
+  cmd.clear();
+  cmd.push_back("./nonexistent-command");
+  rc = executeAndWait(cmd, "nonexistent-command description", true);
+  assert(rc != 0);
+
+  cmd.clear();
+  cmd.push_back("./nonexistent-command");
+  cmd.push_back("arg");
+  rc = executeAndWait(cmd, "nonexistent-command description", true);
+  assert(rc != 0);
+
+  cmd.clear();
+  cmd.push_back("/this/path/does/not/exist");
+  rc = executeAndWait(cmd, "path does not exist description", true);
+  assert(rc != 0);
+
+  cmd.clear();
+  cmd.push_back("/this/path/does/not/exist");
+  cmd.push_back("arg");
+  rc = executeAndWait(cmd, "path does not exist description", true);
+  assert(rc != 0);
+}
+
+// check that we can run /usr/bin/env and get 0 return code from it
+static void checkEnv() {
+  int rc;
+  std::vector<std::string> cmd;
+
+  cmd.clear();
+  cmd.push_back("/usr/bin/env");
+  rc = executeAndWait(cmd, "testing that env can be run", true);
+  assert(rc == 0);
+
+}
+
+int main(int argc, char** argv) {
+
+  checkNonexistent();
+  checkEnv();
+
+  return 0;
+}