Add gtest cases for ISR

wiringPi/gtest/run_isr.cpp

@@ -0,0 +1,31 @@
+/*
+ * Helper program of test_conflict_between_processes.
+ *
+ * The program configures ISR on pin 31 (BCM 1) and polls for a termination request.
+ */
+#include <stdint.h>
+#include <stdio.h>
+#include <wiringPi.h>
+
+#define LISTENER_PIN 31  // BCM 1
+
+static uint8_t ok_to_stop = 0;
+static void noop() {
+  fprintf(stderr, "interrupted\n");
+  ok_to_stop = 1;
+}
+
+int main(int, char *[]) {
+  fprintf(stderr, "start\n");
+  wiringPiSetup();
+  if (wiringPiISR(LISTENER_PIN, INT_EDGE_RISING, noop)) {
+    fprintf(stderr, "failed to start listener\n");
+    return -1;
+  }
+  fprintf(stderr, "start listening\n");
+
+  while (!ok_to_stop) {
+    delay(1000);
+  }
+  fprintf(stderr, "bye\n");
+}