Adding failure logs to TCP echo test.

This adds some extra logs to the test for debugging purposes. Also
allows the test to fail immediately if it fails to obtain an IP address.

Author: bridadan

features/FEATURE_LWIP/TESTS/mbedmicro-net/tcp_echo/main.cpp

@@ -30,9 +30,13 @@ void prep_buffer(char *tx_buffer, size_t tx_size) {
 
 int main() {
     GREENTEA_SETUP(60, "tcp_echo");
-
     EthernetInterface eth;
-    eth.connect();
+    int err = eth.connect();
+
+    if (err) {
+        printf("MBED: failed to connect with an error of %d\r\n", err);
+        GREENTEA_TESTSUITE_RESULT(false);
+    }
 
     printf("MBED: TCPClient IP address is '%s'\n", eth.get_ip_address());
     printf("MBED: TCPClient waiting for server IP and port...\n");
@@ -64,12 +68,12 @@ int main() {
 
         prep_buffer(tx_buffer, sizeof(tx_buffer));
         sock.send(tx_buffer, sizeof(tx_buffer));
-
+        printf("MBED: Finished sending\r\n");
         // Server will respond with HTTP GET's success code
         const int ret = sock.recv(rx_buffer, sizeof(rx_buffer));
-        
+        printf("MBED: Finished receiving\r\n");
+
         result = !memcmp(tx_buffer, rx_buffer, sizeof(tx_buffer));
-        
         TEST_ASSERT_EQUAL(ret, sizeof(rx_buffer));
         TEST_ASSERT_EQUAL(true, result);
     }