Fix regression in WiFi.onEvent, add testcase (thanks @everslick)

libraries/ESP8266WiFi/src/ESP8266WiFiGeneric.cpp

@@ -92,6 +92,7 @@ void ESP8266WiFiGenericClass::onEvent(WiFiEventCb f, WiFiEvent_t event)
         (*f)(static_cast<WiFiEvent>(e->event));
     });
     handler->mCanExpire = false;
+    sCbEventList.push_back(handler);
 }
 
 WiFiEventHandler ESP8266WiFiGenericClass::onStationModeConnected(std::function<void(const WiFiEventStationModeConnected&)> f)

tests/device/test_WiFi_events/test_WiFi_events.ino

@@ -0,0 +1,130 @@
+#include <map>
+#include <Arduino.h>
+#include <ESP8266WiFi.h>
+#include <ESP8266HTTPClient.h>
+#include <BSTest.h>
+#include <test_config.h>
+#include <pgmspace.h>
+
+BS_ENV_DECLARE();
+
+void setup()
+{
+    Serial.begin(115200);
+    Serial.setDebugOutput(false);
+    WiFi.persistent(false);
+    WiFi.mode(WIFI_OFF);
+    BS_RUN(Serial);
+}
+
+static std::map<WiFiEvent_t, int> sEventsReceived;
+
+static void onWiFiEvent(WiFiEvent_t event)
+{
+    sEventsReceived[event]++;
+}
+
+TEST_CASE("WiFi.onEvent is called for specific events", "[wifi][events]")
+{
+    sEventsReceived[WIFI_EVENT_STAMODE_CONNECTED] = 0;
+    sEventsReceived[WIFI_EVENT_STAMODE_DISCONNECTED] = 0;
+    sEventsReceived[WIFI_EVENT_STAMODE_GOT_IP] = 0;
+
+    WiFi.onEvent(onWiFiEvent, WIFI_EVENT_STAMODE_CONNECTED);
+    WiFi.onEvent(onWiFiEvent, WIFI_EVENT_STAMODE_DISCONNECTED);
+    WiFi.onEvent(onWiFiEvent, WIFI_EVENT_STAMODE_GOT_IP);
+    WiFi.onEvent(onWiFiEvent, WIFI_EVENT_ANY);
+
+    WiFi.mode(WIFI_STA);
+    WiFi.begin(STA_SSID, STA_PASS);
+    unsigned long start = millis();
+    while (WiFi.status() != WL_CONNECTED) {
+        delay(500);
+        REQUIRE(millis() - start < 5000);
+    }
+    WiFi.disconnect();
+    delay(100);
+    WiFi.mode(WIFI_OFF);
+    REQUIRE(sEventsReceived[WIFI_EVENT_STAMODE_CONNECTED] == 2);
+    REQUIRE(sEventsReceived[WIFI_EVENT_STAMODE_DISCONNECTED] >= 2 && sEventsReceived[WIFI_EVENT_STAMODE_DISCONNECTED] % 2 == 0);
+    REQUIRE(sEventsReceived[WIFI_EVENT_STAMODE_GOT_IP] == 2);
+}
+
+TEST_CASE("STA mode events are called both when using DHCP and static config", "[wifi][events]")
+{
+    String events;
+    
+    auto handler1 = WiFi.onStationModeConnected([&](const WiFiEventStationModeConnected& evt){
+        events += "connected,";
+    });  
+    auto handler2 = WiFi.onStationModeDisconnected([&](const WiFiEventStationModeDisconnected& evt){
+        if (events.length()) {
+            events += "disconnected,";
+        }
+    });
+    auto handler3 = WiFi.onStationModeGotIP([&](const WiFiEventStationModeGotIP& evt){
+        events += "got_ip,";
+    });
+
+    // run the test with DHCP
+    WiFi.mode(WIFI_STA);
+    WiFi.begin(STA_SSID, STA_PASS);
+    unsigned long start = millis();
+    while (WiFi.status() != WL_CONNECTED) {
+        delay(500);
+        REQUIRE(millis() - start < 5000);
+    }
+    // save IP config
+    IPAddress localIP = WiFi.localIP();
+    IPAddress subnetMask = WiFi.subnetMask();
+    IPAddress gatewayIP = WiFi.gatewayIP();
+    WiFi.disconnect();
+    delay(100);
+
+    REQUIRE(events == "connected,got_ip,disconnected,");
+    events = String();
+
+    // now run the same with static IP config saved above
+
+    WiFi.mode(WIFI_STA);
+    WiFi.config(localIP, gatewayIP, subnetMask);
+    WiFi.begin(STA_SSID, STA_PASS);
+    start = millis();
+    while (WiFi.status() != WL_CONNECTED) {
+        delay(500);
+        REQUIRE(millis() - start < 5000);
+    }
+    WiFi.disconnect();
+    delay(100);
+    WiFi.mode(WIFI_OFF);
+    REQUIRE(events == "connected,got_ip,disconnected,");
+}
+
+TEST_CASE("Events are not called if handler is deleted", "[wifi][events]")
+{
+    String events;
+    
+    WiFi.onStationModeConnected([&](const WiFiEventStationModeConnected& evt){
+        events += "connected,";
+    });  
+    WiFi.onStationModeDisconnected([&](const WiFiEventStationModeDisconnected& evt){
+        events += "disconnected,";
+    });
+    WiFi.onStationModeGotIP([&](const WiFiEventStationModeGotIP& evt){
+        events += "got_ip,";
+    });
+
+    WiFi.mode(WIFI_STA);
+    WiFi.begin(STA_SSID, STA_PASS);
+    unsigned long start = millis();
+    while (WiFi.status() != WL_CONNECTED) {
+        delay(500);
+        REQUIRE(millis() - start < 5000);
+    }
+    WiFi.disconnect();
+    delay(100);
+
+    REQUIRE(events == "");
+}
+
+void loop() {}