Arduino code to test how long ESP8266 takes to connect to WiFi at power up.

ConnectionTestLoop.ino

#include <ESP8266WiFi.h>          //https://github.com/esp8266/Arduino
#include <WiFiManager.h>          //https://github.com/kentaylor/WiFiManager
const unsigned long ONE_SECOND = 1000 * 1000;

int start;
int now;
int codeTime;
IPAddress ip= IPAddress(192,168,1,27);
IPAddress gw= IPAddress(192,168,1,1);
IPAddress subnet= IPAddress(255,255,255,0);
IPAddress dns= IPAddress(192,168,1,1);
static struct station_config conf;
char mac[18] = { 0 };
void setup() {
  start = millis();
  WiFi.config(ip,gw,subnet, dns); 
  WiFi.begin("SSID","password");
  while (WiFi.status() != WL_CONNECTED) {
        delay(1);
    }
  now = millis();
  codeTime = now - start;
  wifi_station_get_config(&conf);
  //conf.bssid[0]=conf.bssid[0]+1;
  //WiFi.begin("SSID","password",6,conf.bssid,1);
  Serial.begin(115200);
}

void loop() {
  printf("SDK version:%s\n", system_get_sdk_version());
  Serial.print("Start millis = "); 
  Serial.println(start); 
  Serial.print("Now millis = "); 
  Serial.println(now);
  Serial.print("Program Time = "); 
  Serial.println(codeTime);
  sprintf(mac, "%02X:%02X:%02X:%02X:%02X:%02X", conf.bssid[0], conf.bssid[1], conf.bssid[2], conf.bssid[3], conf.bssid[4], conf.bssid[5]);
  Serial.println(mac);
  delay(10000); 
}