Add gtest cases for ISR

wiringPi/gtest/test_isr_conflict_between_processes.cpp

@@ -0,0 +1,68 @@
+#include <gtest/gtest.h>
+#include <pthread.h>
+#include <stdio.h>
+#include <time.h>
+#include <unistd.h>
+#include <wiringPi.h>
+
+#define TRIGGER_PIN  26  // BCM 12
+#define LISTENER_PIN 31  // BCM 1
+#define ANOTHER_LISTENER_PIN 28  // BCM 20
+
+static void *remote_isr(void *) {
+  std::system("./bin/run_isr");
+  return NULL;
+}
+
+/**
+ * Tests ISR setup conflict between two processes.
+ *
+ * Another program 'run_isr' starts first that occupies the pin 31 for an ISR.
+ * This program should fail to start ISR on the same pin.
+ */
+class ISRConflict : public ::testing::Test {
+ public:
+  static void SetUpTestSuite() {
+    wiringPiSetup();
+    digitalWrite(TRIGGER_PIN, LOW);
+
+    pthread_t tid;
+    pthread_create(&tid, NULL, remote_isr, NULL);
+    delay(1000);
+  }
+
+  static void TearDownTestSuite() {
+      delay(1000);
+  }
+
+  static uint32_t count;
+
+  static void TriggerCount() { ++count; }
+  static void TriggerCount2(WPIWfiStatus, void *userdata) {
+    ++*(uint32_t *)userdata;
+  }
+
+ protected:
+  virtual void SetUp() { count = 0; }
+
+  virtual void TearDown() {
+    digitalWrite(TRIGGER_PIN, LOW);
+    delay(10);
+  }
+};
+
+uint32_t ISRConflict::count = 0;
+
+TEST_F(ISRConflict, TestConflictBetweenProcesses) {
+  // The ISRs should fail to start because run_isr is listening on the
+  // same port
+  EXPECT_EQ(
+      wiringPiISR(LISTENER_PIN, INT_EDGE_FALLING, ISRConflict::TriggerCount),
+      -1);
+  EXPECT_EQ(wiringPiISR2(LISTENER_PIN, INT_EDGE_FALLING,
+                         ISRConflict::TriggerCount2, 0, &ISRConflict::count),
+            -1);
+
+  // to exit run_isr
+  digitalWrite(TRIGGER_PIN, HIGH);
+}