Added more tests. Tweaks.

Receiving an http request/response will now return errors like HttpHeaderTooBig, instead of the type being set to that.

Added fr::Socket::status_to_string for converting status values into English strings.

tests/SocketTest.cpp

@@ -0,0 +1,32 @@
+//
+// Created by fred.nicolson on 25/09/17.
+//
+
+#include <gtest/gtest.h>
+#include <frnetlib/Socket.h>
+
+TEST(SocketTest, status_to_string_valid)
+{
+    ASSERT_EQ(fr::Socket::status_to_string(fr::Socket::Status::Unknown), "Unknown");
+    ASSERT_EQ(fr::Socket::status_to_string(fr::Socket::Status::HttpBodyTooBig), "HTTP body too big");
+}
+
+TEST(SocketTest, status_to_string_invalid)
+{
+    try
+    {
+        auto str = fr::Socket::status_to_string(static_cast<fr::Socket::Status>(-1));
+    }
+    catch(const std::logic_error &)
+    {
+        try
+        {
+            auto str = fr::Socket::status_to_string(static_cast<fr::Socket::Status>(99999));
+        }
+        catch(const std::logic_error &)
+        {
+            return;
+        }
+    }
+    ASSERT_TRUE(false);
+}