Add gtest cases for ISR

wiringPi/gtest/test_isr_falling.cpp

@@ -0,0 +1,57 @@
+#include <gtest/gtest.h>
+#include <time.h>
+#include <wiringPi.h>
+
+#define TRIGGER_PIN  26  // BCM 12
+#define LISTENER_PIN 31  // BCM 1
+
+/**
+ * Tests ISR for falling edges.
+ */
+class ISRFalling : public ::testing::Test {
+ public:
+  static void SetUpTestSuite() {
+    wiringPiSetup();
+    pinMode(TRIGGER_PIN, OUTPUT);
+    digitalWrite(TRIGGER_PIN, HIGH);
+    wiringPiISR(LISTENER_PIN, INT_EDGE_FALLING, ISRFalling::TriggerCount);
+    delay(100);
+  }
+
+  static void TearDownTestSuite() { digitalWrite(TRIGGER_PIN, LOW); }
+
+  static uint32_t count;
+  static void TriggerCount() { ++count; }
+
+ protected:
+  virtual void SetUp() { count = 0; }
+
+  virtual void TearDown() {
+    digitalWrite(TRIGGER_PIN, HIGH);
+    delay(10);
+  }
+};
+
+uint32_t ISRFalling::count = 0;
+
+TEST_F(ISRFalling, Fundamental) {
+  EXPECT_EQ(count, 0u);
+  digitalWrite(TRIGGER_PIN, LOW);
+  delay(10);
+  EXPECT_EQ(count, 1u);
+  digitalWrite(TRIGGER_PIN, HIGH);
+  delay(10);
+  EXPECT_EQ(count, 1u);
+}
+
+TEST_F(ISRFalling, ThreeTriggers) {
+  digitalWrite(TRIGGER_PIN, LOW);
+  delay(10);
+  count = 0;
+  for (int i = 0; i < 6; ++i) {
+    delay(10);
+    digitalWrite(TRIGGER_PIN, (i + 1) % 2);
+  }
+  delay(10);
+  EXPECT_EQ(count, 3u);
+}