Better DNS error handling (#1249)

* Better DNS error handling

* Update httpie/core.py

Co-authored-by: Batuhan Taskaya <isidentical@gmail.com>

Co-authored-by: Jakub Roztocil <jakub@roztocil.co>

tests/test_errors.py

@@ -1,3 +1,5 @@
+import pytest
+import socket
 from unittest import mock
 from pytest import raises
 from requests import Request
@@ -31,6 +33,21 @@ def test_error_traceback(program):
         http('--traceback', 'www.google.com')
 
 
+@mock.patch('httpie.core.program')
+@pytest.mark.parametrize("error_code, expected_message", [
+    (socket.EAI_AGAIN, "check your connection"),
+    (socket.EAI_NONAME, "check the URL"),
+])
+def test_error_custom_dns(program, error_code, expected_message):
+    exc = ConnectionError('Connection aborted')
+    exc.__context__ = socket.gaierror(error_code, "<test>")
+    program.side_effect = exc
+
+    r = http('www.google.com', tolerate_error_exit_status=True)
+    assert r.exit_status == ExitStatus.ERROR
+    assert expected_message in r.stderr
+
+
 def test_max_headers_limit(httpbin_both):
     with raises(ConnectionError) as e:
         http('--max-headers=1', httpbin_both + '/get')