CtsNetTests: Fix WifiInfoTest

According to the public documentation of WifiInfo.getSSID(), the
returned value can be one of the following:
1. Hex digits if the SSID cannot be decoded as UTF-8.
2. String surrounded by double quotes if the SSID can be decoded as
UTF-8.
3. <unknown ssid>, if not connected.

Fix the test to check for all these 3 string values.

BUG: 31272462
TEST: The failing CTS test passes now.
Change-Id: I26e12d28994e3cdb4cd1bd9e999633b327ad5830
diff --git a/tests/cts/net/src/android/net/wifi/cts/WifiInfoTest.java b/tests/cts/net/src/android/net/wifi/cts/WifiInfoTest.java
index 8719b6b..696d215 100644
--- a/tests/cts/net/src/android/net/wifi/cts/WifiInfoTest.java
+++ b/tests/cts/net/src/android/net/wifi/cts/WifiInfoTest.java
@@ -26,6 +26,7 @@
 import android.net.wifi.WifiInfo;
 import android.net.wifi.WifiManager;
 import android.net.wifi.WifiManager.WifiLock;
+import android.net.wifi.WifiSsid;
 import android.test.AndroidTestCase;
 
 import java.util.concurrent.Callable;
@@ -123,7 +124,7 @@
         SupplicantState.isValidState(wifiInfo.getSupplicantState());
         WifiInfo.getDetailedStateOf(SupplicantState.DISCONNECTED);
         String ssid = wifiInfo.getSSID();
-        if (ssid.startsWith("0x") == false) {
+        if (!ssid.startsWith("0x") && !ssid.equals(WifiSsid.NONE)) {
             // Non-hex string should be quoted
             assertTrue(ssid.charAt(0) == '"');
             assertTrue(ssid.charAt(ssid.length() - 1) == '"');