Adding BluetoothTestBase::CheckNotifySessionValue() method

device/bluetooth/test/bluetooth_test_mac.mm

Index: device/bluetooth/test/bluetooth_test_mac.mm
diff --git a/device/bluetooth/test/bluetooth_test_mac.mm b/device/bluetooth/test/bluetooth_test_mac.mm
index eb4bf905e330bb81166f50a4af60aa57b42aeeff..2a0947fff0c03809d26a2142f703887070feb5d4 100644
--- a/device/bluetooth/test/bluetooth_test_mac.mm
+++ b/device/bluetooth/test/bluetooth_test_mac.mm
@@ -465,6 +465,18 @@ void BluetoothTestMac::SimulateGattCharacteristicRemoved(
   [peripheral_mock mockDidDiscoverEvents];
 }
 
+void BluetoothTestMac::CheckNotifySessionValue(
+    uint16_t expected_config_descriptor_value,
+    int attempts) {
+  EXPECT_EQ(attempts, gatt_notify_characteristic_attempts_);
+  if (expected_config_descriptor_value == 0) {
+    EXPECT_TRUE(last_notify_value);
+  } else if (expected_config_descriptor_value == 1 ||
+             expected_config_descriptor_value == 2) {
+    EXPECT_FALSE(last_notify_value);
+  }
+}
+
 void BluetoothTestMac::OnFakeBluetoothDeviceConnectGattCalled() {
   gatt_connection_attempts_++;
 }