This stand alone sketch checks the WiFi functionality of an Arduino board with the WiFi shield or an Intel Galileo board.

WiFiChecker.ino

/*
// This code is to test WiFi function on Arduino Boards
// It was complied from various examples which can be found:
//
// http://arduino.cc/en/Tutorial/ConnectNoEncryption
// http://arduino.cc/en/Tutorial/ConnectWithWPA
// http://arduino.cc/en/Tutorial/WiFiWebClientRepeating
// http://arduino.cc/en/Reference/WiFiClientConnect
//
// Carlyn Maw 2014
// www.carlynorama.com
// This code is released to the public domain
*/

#include <WiFi.h>

char ssid[] = "CHANGE_TO_YOUR_NETWORK_NAME";     //  your network SSID (name) 
char pass[] = "CHANGE_TO_YOUR_NETWORK_PASSWORD";  // your network password
int status = WL_IDLE_STATUS;     // the Wifi radio's status


// ------------------------------------------------------------- setup()
void setup() {
  //Delay start so serial communication and sketch updating
  //dont intrfere with each other on the Intel Galileo board
  delay(5000);

  //Intialize serial
  Serial.begin(9600); 

  //Both of the below functions connect to the wifi card
  //and verify that a connection to the local network
  //has been made.
  wifiNotEncrypted();
  //wifiEncrypted();

  connectToTestPage();


}
// --------------------------------------------------------- END setup()

// -------------------------------------------------------------- loop()
void loop() {
  // put your main code here, to run repeatedly: 

}
// ---------------------------------------------------------- END loop()



// -------------------------------------------------- wifiNotEncrypted()
void wifiNotEncrypted() {

  // check for the presence of the shield:
  if (WiFi.status() == WL_NO_SHIELD) {
    Serial.println("WiFi shield not present"); 
    // don't continue:
    while(true);
  } 

  String fv = WiFi.firmwareVersion();
  if( fv != "1.1.0" )
    Serial.println("Please upgrade the firmware");

  // attempt to connect to Wifi network:
  while ( status != WL_CONNECTED) { 
    Serial.print("Attempting to connect to open SSID: ");
    Serial.println(ssid);
    status = WiFi.begin(ssid);

    // wait 10 seconds for connection:
    delay(10000);
  }

  // you're connected now, so print out the data:
  Serial.print("You're connected to the network\n");
  printCurrentNet();
  printWifiData();
}
// ---------------------------------------------- END wifiNotEncrypted()

//------------------------------------------------------ wifiEncrypted()
void wifiEncrypted() {
  // check for the presence of the shield:
  if (WiFi.status() == WL_NO_SHIELD) {
    Serial.println("WiFi shield not present"); 
    // don't continue:
    while(true);
  } 

  String fv = WiFi.firmwareVersion();
  if( fv != "1.1.0" )
    Serial.println("Please upgrade the firmware");

  // attempt to connect to Wifi network:
  while ( status != WL_CONNECTED) { 
    Serial.print("Attempting to connect to WPA SSID: ");
    Serial.println(ssid);
    // Connect to WPA/WPA2 network:    
    status = WiFi.begin(ssid, pass);

    // wait 10 seconds for connection:
    delay(10000);
  }

  // you're connected now, so print out the data:
  Serial.print("You're connected to the network\n");
  printCurrentNet();
  printWifiData();
}
//-------------------------------------------------- END wifiEncrypted()

//------------------------------------------------------ printWifiData()
void printWifiData() {
  // print your WiFi shield's IP address:
  IPAddress ip = WiFi.localIP();
  Serial.print("IP Address: ");
  Serial.println(ip);

  // print your MAC address:
  byte mac[6];  
  WiFi.macAddress(mac);
  Serial.print("MAC address: ");
  Serial.print(mac[5],HEX);
  Serial.print(":");
  Serial.print(mac[4],HEX);
  Serial.print(":");
  Serial.print(mac[3],HEX);
  Serial.print(":");
  Serial.print(mac[2],HEX);
  Serial.print(":");
  Serial.print(mac[1],HEX);
  Serial.print(":");
  Serial.println(mac[0],HEX);

}
//-------------------------------------------------- END printWifiData()

//---------------------------------------------------- printCurrentNet()
void printCurrentNet() {
  // print the SSID of the network you're attached to:
  Serial.print("SSID: ");
  Serial.println(WiFi.SSID());

  // print the MAC address of the router you're attached to:
  byte bssid[6];
  WiFi.BSSID(bssid);    
  Serial.print("BSSID: ");
  Serial.print(bssid[5],HEX);
  Serial.print(":");
  Serial.print(bssid[4],HEX);
  Serial.print(":");
  Serial.print(bssid[3],HEX);
  Serial.print(":");
  Serial.print(bssid[2],HEX);
  Serial.print(":");
  Serial.print(bssid[1],HEX);
  Serial.print(":");
  Serial.println(bssid[0],HEX);

  // print the received signal strength:
  long rssi = WiFi.RSSI();
  Serial.print("signal strength (RSSI):");
  Serial.println(rssi);

  // print the encryption type:
  byte encryption = WiFi.encryptionType();
  Serial.print("Encryption Type:");
  Serial.println(encryption,HEX);
  Serial.println();
}
//------------------------------------------------ END printCurrentNet()

//-------------------------------------------------- connectToTestPage()
void connectToTestPage() {
  char server[] = "www.arduino.cc"; 
  WiFiClient client;

  // if there's a successful connection:
  if (client.connect(server, 80)) {
    Serial.println("connecting...");
    // send the HTTP PUT request:
    client.println("GET /latest.txt HTTP/1.1");
    client.println("Host: www.arduino.cc");
    client.println("User-Agent: ArduinoWiFi/1.1");
    client.println("Connection: close");
    client.println();

    while (client.available()) {
      char c = client.read();
      Serial.write(c);
    } 
  }
  else {
    // if you couldn't make a connection:
    Serial.println("connection failed");
  }

  if (!client.connected()) {
    Serial.println();
    Serial.println("disconnecting from server.");
    client.stop();
  }
}
//---------------------------------------------- END connectToTestPage()

//---------------------------------------------------- connectToGoogle()
void connectToGoogle() {
  char server[] = "www.google.com"; 
  WiFiClient client;
  Serial.println("\nStarting connection to server...");
  // if you get a connection, report back via serial:
  if (client.connect(server, 80)) {
    Serial.println("connected to server");
    // Make a HTTP request:
    client.println("GET /search?q=arduino HTTP/1.1");
    client.println("Host: www.google.com");
    client.println("Connection: close");
    client.println();

    while (client.available()) {
      char c = client.read();
      Serial.write(c);
    } 
  }
  else {
    // if you couldn't make a connection:
    Serial.println("connection failed");
  }

  // if the server's disconnected, stop the client:
  if (!client.connected()) {
    Serial.println();
    Serial.println("disconnecting from server.");
    client.stop();
  }
}
//------------------------------------------------ END connectToGoogle()