Merge pull request #13654 from balajicyp/topic/wep_security_fix_testcase_update

Summary of changes
Remove WEP security Test Case with NULL as WEP security Key are sequence of Hex Values , the character "NULL" is (0x00) it is a valid value ( for ex: this is key index, followed by length and hex key array).

Impact of changes
Remove the test case for NULL( "" )key with NSAPI_SECURITY_WEP to test return value with NSAPI_ERROR_PARAMETER

The set_credentials(const char *ssid, const char *pass, nsapi_security_t security) API has no key length, the key length is derived by using strlen(pass), which works if the pass ( is a string) , but in case of NSAPI_SECURITY_WEP and NSAPI_SECURITY_WPA2_ENT, the key does not happen to be string but a hex char array.

WEP security Key are sequence of Hex Values , the character "NULL" is (0x00) it is a valid value ( for ex: this is key index, followed by length and hex key array).

The key index 0 , 1, 2, 3 are keys used for an WiFi Access point.

Author: 0xc0170

connectivity/netsocket/tests/TESTS/network/wifi/wifi_set_credential.cpp

@@ -43,9 +43,6 @@ void wifi_set_credential(void)
     error = iface->set_credentials("OK", NULL, NSAPI_SECURITY_WEP);
     TEST_ASSERT_EQUAL(NSAPI_ERROR_PARAMETER, error);
 
-    error = iface->set_credentials("OK", "", NSAPI_SECURITY_WEP);
-    TEST_ASSERT_EQUAL(NSAPI_ERROR_PARAMETER, error);
-
     error = iface->set_credentials("OK", NULL, NSAPI_SECURITY_WPA_WPA2);
     TEST_ASSERT_EQUAL(NSAPI_ERROR_PARAMETER, error);