diff --git a/httpie/models.py b/httpie/models.py
index af6163fd..d7c5414f 100644
--- a/httpie/models.py
+++ b/httpie/models.py
@@ -105,8 +105,13 @@ class HTTPRequest(HTTPMessage):
         if 'Host' not in self._orig.headers:
             headers['Host'] = url.netloc.split('@')[-1]
 
-        headers = ['%s: %s' % (name, value)
-                   for name, value in headers.items()]
+        headers = [
+            '%s: %s' % (
+                name,
+                value if isinstance(value, str) else value.decode('utf8')
+            )
+            for name, value in headers.items()
+        ]
 
         headers.insert(0, request_line)
         headers = '\r\n'.join(headers).strip()
diff --git a/requirements-dev.txt b/requirements-dev.txt
index bd00cc55..1b0b06ae 100644
--- a/requirements-dev.txt
+++ b/requirements-dev.txt
@@ -2,4 +2,5 @@ tox
 pytest
 pytest-xdist
 pytest-cov
+pytest-httpbin
 docutils
diff --git a/setup.py b/setup.py
index 7a23a277..a4cc2719 100644
--- a/setup.py
+++ b/setup.py
@@ -26,6 +26,7 @@ class PyTest(TestCommand):
 
 tests_require = [
     'pytest',
+    'pytest-httpbin',
 ]
 
 
diff --git a/tests/test_auth.py b/tests/test_auth.py
index 1977a064..53962615 100644
--- a/tests/test_auth.py
+++ b/tests/test_auth.py
@@ -2,42 +2,45 @@
 import requests
 import pytest
 
-from utils import http, httpbin, HTTP_OK
+from utils import http, add_auth, HTTP_OK
 import httpie.input
 
 
 class TestAuth:
-    def test_basic_auth(self):
+    def test_basic_auth(self, httpbin):
         r = http('--auth=user:password',
-                 'GET', httpbin('/basic-auth/user/password'))
+                 'GET', httpbin.url + '/basic-auth/user/password')
         assert HTTP_OK in r
         assert r.json == {'authenticated': True, 'user': 'user'}
 
     @pytest.mark.skipif(
         requests.__version__ == '0.13.6',
         reason='Redirects with prefetch=False are broken in Requests 0.13.6')
-    def test_digest_auth(self):
+    def test_digest_auth(self, httpbin):
         r = http('--auth-type=digest', '--auth=user:password',
-                 'GET', httpbin('/digest-auth/auth/user/password'))
+                 'GET', httpbin.url + '/digest-auth/auth/user/password')
         assert HTTP_OK in r
         assert r.json == {'authenticated': True, 'user': 'user'}
 
-    def test_password_prompt(self):
+    def test_password_prompt(self, httpbin):
         httpie.input.AuthCredentials._getpass = lambda self, prompt: 'password'
-        r = http('--auth', 'user', 'GET', httpbin('/basic-auth/user/password'))
+        r = http('--auth', 'user',
+                 'GET', httpbin.url + '/basic-auth/user/password')
         assert HTTP_OK in r
         assert r.json == {'authenticated': True, 'user': 'user'}
 
-    def test_credentials_in_url(self):
-        url = httpbin('/basic-auth/user/password', auth='user:password')
+    def test_credentials_in_url(self, httpbin):
+        url = add_auth(httpbin.url + '/basic-auth/user/password',
+                       auth='user:password')
         r = http('GET', url)
         assert HTTP_OK in r
         assert r.json == {'authenticated': True, 'user': 'user'}
 
-    def test_credentials_in_url_auth_flag_has_priority(self):
+    def test_credentials_in_url_auth_flag_has_priority(self, httpbin):
         """When credentials are passed in URL and via -a at the same time,
          then the ones from -a are used."""
-        url = httpbin('/basic-auth/user/password', auth='user:wrong')
+        url = add_auth(httpbin.url + '/basic-auth/user/password',
+                       auth='user:wrong')
         r = http('--auth=user:password', 'GET', url)
         assert HTTP_OK in r
         assert r.json == {'authenticated': True, 'user': 'user'}
diff --git a/tests/test_binary.py b/tests/test_binary.py
index 7a1bd062..7c112045 100644
--- a/tests/test_binary.py
+++ b/tests/test_binary.py
@@ -1,30 +1,30 @@
 """Tests for dealing with binary request and response data."""
 from httpie.compat import urlopen
 from httpie.output.streams import BINARY_SUPPRESSED_NOTICE
-from utils import TestEnvironment, http, httpbin
+from utils import TestEnvironment, http
 from fixtures import BIN_FILE_PATH, BIN_FILE_CONTENT, BIN_FILE_PATH_ARG
 
 
 class TestBinaryRequestData:
-    def test_binary_stdin(self):
+    def test_binary_stdin(self, httpbin):
         with open(BIN_FILE_PATH, 'rb') as stdin:
             env = TestEnvironment(
                 stdin=stdin,
                 stdin_isatty=False,
                 stdout_isatty=False
             )
-            r = http('--print=B', 'POST', httpbin('/post'), env=env)
+            r = http('--print=B', 'POST', httpbin.url + '/post', env=env)
             assert r == BIN_FILE_CONTENT
 
-    def test_binary_file_path(self):
+    def test_binary_file_path(self, httpbin):
         env = TestEnvironment(stdin_isatty=True, stdout_isatty=False)
-        r = http('--print=B', 'POST', httpbin('/post'),
+        r = http('--print=B', 'POST', httpbin.url + '/post',
                  '@' + BIN_FILE_PATH_ARG, env=env, )
         assert r == BIN_FILE_CONTENT
 
-    def test_binary_file_form(self):
+    def test_binary_file_form(self, httpbin):
         env = TestEnvironment(stdin_isatty=True, stdout_isatty=False)
-        r = http('--print=B', '--form', 'POST', httpbin('/post'),
+        r = http('--print=B', '--form', 'POST', httpbin.url + '/post',
                  'test@' + BIN_FILE_PATH_ARG, env=env)
         assert bytes(BIN_FILE_CONTENT) in bytes(r)
 
diff --git a/tests/test_cli.py b/tests/test_cli.py
index c19fcb29..103d9543 100644
--- a/tests/test_cli.py
+++ b/tests/test_cli.py
@@ -9,7 +9,7 @@ from httpie import input
 from httpie.input import KeyValue, KeyValueArgType
 from httpie import ExitStatus
 from httpie.cli import parser
-from utils import TestEnvironment, http, httpbin, HTTP_OK
+from utils import TestEnvironment, http, HTTP_OK
 from fixtures import (
     FILE_PATH_ARG, JSON_FILE_PATH_ARG,
     JSON_FILE_CONTENT, FILE_CONTENT, FILE_PATH
@@ -93,27 +93,28 @@ class TestItemParsing:
 
 
 class TestQuerystring:
-    def test_query_string_params_in_url(self):
-        r = http('--print=Hhb', 'GET', httpbin('/get?a=1&b=2'))
+    def test_query_string_params_in_url(self, httpbin):
+        r = http('--print=Hhb', 'GET', httpbin.url + '/get?a=1&b=2')
         path = '/get?a=1&b=2'
-        url = httpbin(path)
+        url = httpbin.url + path
         assert HTTP_OK in r
         assert 'GET %s HTTP/1.1' % path in r
         assert '"url": "%s"' % url in r
 
-    def test_query_string_params_items(self):
-        r = http('--print=Hhb', 'GET', httpbin('/get'), 'a==1', 'b==2')
-        path = '/get?a=1&b=2'
-        url = httpbin(path)
+    def test_query_string_params_items(self, httpbin):
+        r = http('--print=Hhb', 'GET', httpbin.url + '/get', 'a==1')
+        path = '/get?a=1'
+        url = httpbin.url + path
         assert HTTP_OK in r
         assert 'GET %s HTTP/1.1' % path in r
         assert '"url": "%s"' % url in r
 
-    def test_query_string_params_in_url_and_items_with_duplicates(self):
-        r = http('--print=Hhb', 'GET', httpbin('/get?a=1&a=1'),
-                 'a==1', 'a==1', 'b==2')
-        path = '/get?a=1&a=1&a=1&a=1&b=2'
-        url = httpbin(path)
+    def test_query_string_params_in_url_and_items_with_duplicates(self,
+                                                                  httpbin):
+        r = http('--print=Hhb', 'GET',
+                 httpbin.url + '/get?a=1&a=1', 'a==1', 'a==1')
+        path = '/get?a=1&a=1&a=1&a=1'
+        url = httpbin.url + path
         assert HTTP_OK in r
         assert 'GET %s HTTP/1.1' % path in r
         assert '"url": "%s"' % url in r
@@ -257,12 +258,13 @@ class TestArgumentParser:
 
 
 class TestNoOptions:
-    def test_valid_no_options(self):
-        r = http('--verbose', '--no-verbose', 'GET', httpbin('/get'))
+
+    def test_valid_no_options(self, httpbin):
+        r = http('--verbose', '--no-verbose', 'GET', httpbin.url + '/get')
         assert 'GET /get HTTP/1.1' not in r
 
-    def test_invalid_no_options(self):
-        r = http('--no-war', 'GET', httpbin('/get'),
+    def test_invalid_no_options(self, httpbin):
+        r = http('--no-war', 'GET', httpbin.url + '/get',
                  error_exit_ok=True)
         assert r.exit_status == 1
         assert 'unrecognized arguments: --no-war' in r.stderr
@@ -270,16 +272,18 @@ class TestNoOptions:
 
 
 class TestIgnoreStdin:
-    def test_ignore_stdin(self):
+
+    def test_ignore_stdin(self, httpbin):
         with open(FILE_PATH) as f:
             env = TestEnvironment(stdin=f, stdin_isatty=False)
-            r = http('--ignore-stdin', '--verbose', httpbin('/get'), env=env)
+            r = http('--ignore-stdin', '--verbose', httpbin.url + '/get',
+                     env=env)
         assert HTTP_OK in r
         assert 'GET /get HTTP' in r, "Don't default to POST."
         assert FILE_CONTENT not in r, "Don't send stdin data."
 
-    def test_ignore_stdin_cannot_prompt_password(self):
-        r = http('--ignore-stdin', '--auth=no-password', httpbin('/get'),
+    def test_ignore_stdin_cannot_prompt_password(self, httpbin):
+        r = http('--ignore-stdin', '--auth=no-password', httpbin.url + '/get',
                  error_exit_ok=True)
         assert r.exit_status == ExitStatus.ERROR
         assert 'because --ignore-stdin' in r.stderr
diff --git a/tests/test_defaults.py b/tests/test_defaults.py
index dffbaf6e..652a272b 100644
--- a/tests/test_defaults.py
+++ b/tests/test_defaults.py
@@ -2,34 +2,34 @@
 Tests for the provided defaults regarding HTTP method, and --json vs. --form.
 
 """
-from utils import TestEnvironment, http, httpbin, HTTP_OK
+from utils import TestEnvironment, http, HTTP_OK, no_content_type
 from fixtures import FILE_PATH
 
 
 class TestImplicitHTTPMethod:
-    def test_implicit_GET(self):
-        r = http(httpbin('/get'))
+    def test_implicit_GET(self, httpbin):
+        r = http(httpbin.url + '/get')
         assert HTTP_OK in r
 
-    def test_implicit_GET_with_headers(self):
-        r = http(httpbin('/headers'), 'Foo:bar')
+    def test_implicit_GET_with_headers(self, httpbin):
+        r = http(httpbin.url + '/headers', 'Foo:bar')
         assert HTTP_OK in r
         assert r.json['headers']['Foo'] == 'bar'
 
-    def test_implicit_POST_json(self):
-        r = http(httpbin('/post'), 'hello=world')
+    def test_implicit_POST_json(self, httpbin):
+        r = http(httpbin.url + '/post', 'hello=world')
         assert HTTP_OK in r
         assert r.json['json'] == {'hello': 'world'}
 
-    def test_implicit_POST_form(self):
-        r = http('--form', httpbin('/post'), 'foo=bar')
+    def test_implicit_POST_form(self, httpbin):
+        r = http('--form', httpbin.url + '/post', 'foo=bar')
         assert HTTP_OK in r
         assert r.json['form'] == {'foo': 'bar'}
 
-    def test_implicit_POST_stdin(self):
+    def test_implicit_POST_stdin(self, httpbin):
         with open(FILE_PATH) as f:
             env = TestEnvironment(stdin_isatty=False, stdin=f)
-            r = http('--form', httpbin('/post'), env=env)
+            r = http('--form', httpbin.url + '/post', env=env)
         assert HTTP_OK in r
 
 
@@ -41,66 +41,66 @@ class TestAutoContentTypeAndAcceptHeaders:
 
     """
 
-    def test_GET_no_data_no_auto_headers(self):
+    def test_GET_no_data_no_auto_headers(self, httpbin):
         # https://github.com/jakubroztocil/httpie/issues/62
-        r = http('GET', httpbin('/headers'))
+        r = http('GET', httpbin.url + '/headers')
         assert HTTP_OK in r
         assert r.json['headers']['Accept'] == '*/*'
-        assert 'Content-Type' not in r.json['headers']
+        assert no_content_type(r.json['headers'])
 
-    def test_POST_no_data_no_auto_headers(self):
+    def test_POST_no_data_no_auto_headers(self, httpbin):
         # JSON headers shouldn't be automatically set for POST with no data.
-        r = http('POST', httpbin('/post'))
+        r = http('POST', httpbin.url + '/post')
         assert HTTP_OK in r
         assert '"Accept": "*/*"' in r
         assert '"Content-Type": "application/json' not in r
 
-    def test_POST_with_data_auto_JSON_headers(self):
-        r = http('POST', httpbin('/post'), 'a=b')
+    def test_POST_with_data_auto_JSON_headers(self, httpbin):
+        r = http('POST', httpbin.url + '/post', 'a=b')
         assert HTTP_OK in r
         assert '"Accept": "application/json"' in r
         assert '"Content-Type": "application/json; charset=utf-8' in r
 
-    def test_GET_with_data_auto_JSON_headers(self):
+    def test_GET_with_data_auto_JSON_headers(self, httpbin):
         # JSON headers should automatically be set also for GET with data.
-        r = http('POST', httpbin('/post'), 'a=b')
+        r = http('POST', httpbin.url + '/post', 'a=b')
         assert HTTP_OK in r
         assert '"Accept": "application/json"' in r, r
         assert '"Content-Type": "application/json; charset=utf-8' in r
 
-    def test_POST_explicit_JSON_auto_JSON_accept(self):
-        r = http('--json', 'POST', httpbin('/post'))
+    def test_POST_explicit_JSON_auto_JSON_accept(self, httpbin):
+        r = http('--json', 'POST', httpbin.url + '/post')
         assert HTTP_OK in r
         assert r.json['headers']['Accept'] == 'application/json'
         # Make sure Content-Type gets set even with no data.
         # https://github.com/jakubroztocil/httpie/issues/137
         assert 'application/json' in r.json['headers']['Content-Type']
 
-    def test_GET_explicit_JSON_explicit_headers(self):
-        r = http('--json', 'GET', httpbin('/headers'),
+    def test_GET_explicit_JSON_explicit_headers(self, httpbin):
+        r = http('--json', 'GET', httpbin.url + '/headers',
                  'Accept:application/xml',
                  'Content-Type:application/xml')
         assert HTTP_OK in r
         assert '"Accept": "application/xml"' in r
         assert '"Content-Type": "application/xml"' in r
 
-    def test_POST_form_auto_Content_Type(self):
-        r = http('--form', 'POST', httpbin('/post'))
+    def test_POST_form_auto_Content_Type(self, httpbin):
+        r = http('--form', 'POST', httpbin.url + '/post')
         assert HTTP_OK in r
         assert '"Content-Type": "application/x-www-form-urlencoded' in r
 
-    def test_POST_form_Content_Type_override(self):
-        r = http('--form', 'POST', httpbin('/post'),
+    def test_POST_form_Content_Type_override(self, httpbin):
+        r = http('--form', 'POST', httpbin.url + '/post',
                  'Content-Type:application/xml')
         assert HTTP_OK in r
         assert '"Content-Type": "application/xml"' in r
 
-    def test_print_only_body_when_stdout_redirected_by_default(self):
+    def test_print_only_body_when_stdout_redirected_by_default(self, httpbin):
         env = TestEnvironment(stdin_isatty=True, stdout_isatty=False)
-        r = http('GET', httpbin('/get'), env=env)
+        r = http('GET', httpbin.url + '/get', env=env)
         assert 'HTTP/' not in r
 
-    def test_print_overridable_when_stdout_redirected(self):
+    def test_print_overridable_when_stdout_redirected(self, httpbin):
         env = TestEnvironment(stdin_isatty=True, stdout_isatty=False)
-        r = http('--print=h', 'GET', httpbin('/get'), env=env)
+        r = http('--print=h', 'GET', httpbin.url + '/get', env=env)
         assert HTTP_OK in r
diff --git a/tests/test_downloads.py b/tests/test_downloads.py
index ce722606..3a8c8f24 100644
--- a/tests/test_downloads.py
+++ b/tests/test_downloads.py
@@ -9,7 +9,7 @@ from httpie.downloads import (
     parse_content_range, filename_from_content_disposition, filename_from_url,
     get_unique_filename, ContentRangeError, Download,
 )
-from utils import httpbin, http, TestEnvironment
+from utils import http, TestEnvironment
 
 
 class Response(object):
@@ -94,8 +94,8 @@ class TestDownloadUtils:
 class TestDownloads:
     # TODO: more tests
 
-    def test_actual_download(self):
-        url = httpbin('/robots.txt')
+    def test_actual_download(self, httpbin):
+        url = httpbin.url + '/robots.txt'
         body = urlopen(url).read().decode()
         env = TestEnvironment(stdin_isatty=True, stdout_isatty=False)
         r = http('--download', url, env=env)
@@ -104,11 +104,11 @@ class TestDownloads:
         assert 'Done' in r.stderr
         assert body == r
 
-    def test_download_with_Content_Length(self):
+    def test_download_with_Content_Length(self, httpbin):
         devnull = open(os.devnull, 'w')
         download = Download(output_file=devnull, progress_file=devnull)
         download.start(Response(
-            url=httpbin('/'),
+            url=httpbin.url + '/',
             headers={'Content-Length': 10}
         ))
         time.sleep(1.1)
@@ -118,20 +118,20 @@ class TestDownloads:
         download.finish()
         assert not download.interrupted
 
-    def test_download_no_Content_Length(self):
+    def test_download_no_Content_Length(self, httpbin):
         devnull = open(os.devnull, 'w')
         download = Download(output_file=devnull, progress_file=devnull)
-        download.start(Response(url=httpbin('/')))
+        download.start(Response(url=httpbin.url + '/'))
         time.sleep(1.1)
         download.chunk_downloaded(b'12345')
         download.finish()
         assert not download.interrupted
 
-    def test_download_interrupted(self):
+    def test_download_interrupted(self, httpbin):
         devnull = open(os.devnull, 'w')
         download = Download(output_file=devnull, progress_file=devnull)
         download.start(Response(
-            url=httpbin('/'),
+            url=httpbin.url + '/',
             headers={'Content-Length': 5}
         ))
         download.chunk_downloaded(b'1234')
diff --git a/tests/test_exit_status.py b/tests/test_exit_status.py
index 8e946317..7ac643f9 100644
--- a/tests/test_exit_status.py
+++ b/tests/test_exit_status.py
@@ -2,18 +2,18 @@ import requests
 import pytest
 
 from httpie import ExitStatus
-from utils import TestEnvironment, http, httpbin, HTTP_OK
+from utils import TestEnvironment, http, HTTP_OK
 
 
 class TestExitStatus:
-    def test_ok_response_exits_0(self):
-        r = http('GET', httpbin('/status/200'))
+    def test_ok_response_exits_0(self, httpbin):
+        r = http('GET', httpbin.url + '/status/200')
         assert HTTP_OK in r
         assert r.exit_status == ExitStatus.OK
 
-    def test_error_response_exits_0_without_check_status(self):
-        r = http('GET', httpbin('/status/500'))
-        assert 'HTTP/1.1 500' in r
+    def test_error_response_exits_0_without_check_status(self, httpbin):
+        r = http('GET', httpbin.url + '/status/500')
+        assert '500 INTERNAL SERVER ERRO' in r
         assert r.exit_status == ExitStatus.OK
         assert not r.stderr
 
@@ -21,40 +21,43 @@ class TestExitStatus:
         tuple(map(int, requests.__version__.split('.'))) < (2, 3, 0),
         reason='timeout broken in requests prior v2.3.0 (#185)'
     )
-    def test_timeout_exit_status(self):
+    def test_timeout_exit_status(self, httpbin):
 
-        r = http('--timeout=0.5', 'GET', httpbin('/delay/1'),
+        r = http('--timeout=0.5', 'GET', httpbin.url + '/delay/1',
                  error_exit_ok=True)
         assert r.exit_status == ExitStatus.ERROR_TIMEOUT
 
-    def test_3xx_check_status_exits_3_and_stderr_when_stdout_redirected(self):
+    def test_3xx_check_status_exits_3_and_stderr_when_stdout_redirected(
+            self, httpbin):
         env = TestEnvironment(stdout_isatty=False)
-        r = http('--check-status', '--headers', 'GET', httpbin('/status/301'),
+        r = http('--check-status', '--headers',
+                 'GET', httpbin.url + '/status/301',
                  env=env, error_exit_ok=True)
-        assert 'HTTP/1.1 301' in r
+        assert '301 MOVED PERMANENTLY' in r
         assert r.exit_status == ExitStatus.ERROR_HTTP_3XX
         assert '301 moved permanently' in r.stderr.lower()
 
     @pytest.mark.skipif(
         requests.__version__ == '0.13.6',
         reason='Redirects with prefetch=False are broken in Requests 0.13.6')
-    def test_3xx_check_status_redirects_allowed_exits_0(self):
-        r = http('--check-status', '--follow', 'GET', httpbin('/status/301'),
+    def test_3xx_check_status_redirects_allowed_exits_0(self, httpbin):
+        r = http('--check-status', '--follow',
+                 'GET', httpbin.url + '/status/301',
                  error_exit_ok=True)
         # The redirect will be followed so 200 is expected.
-        assert 'HTTP/1.1 200 OK' in r
+        assert HTTP_OK in r
         assert r.exit_status == ExitStatus.OK
 
-    def test_4xx_check_status_exits_4(self):
-        r = http('--check-status', 'GET', httpbin('/status/401'),
+    def test_4xx_check_status_exits_4(self, httpbin):
+        r = http('--check-status', 'GET', httpbin.url + '/status/401',
                  error_exit_ok=True)
-        assert 'HTTP/1.1 401' in r
+        assert '401 UNAUTHORIZED' in r
         assert r.exit_status == ExitStatus.ERROR_HTTP_4XX
         # Also stderr should be empty since stdout isn't redirected.
         assert not r.stderr
 
-    def test_5xx_check_status_exits_5(self):
-        r = http('--check-status', 'GET', httpbin('/status/500'),
+    def test_5xx_check_status_exits_5(self, httpbin):
+        r = http('--check-status', 'GET', httpbin.url + '/status/500',
                  error_exit_ok=True)
-        assert 'HTTP/1.1 500' in r
+        assert '500 INTERNAL SERVER ERROR' in r
         assert r.exit_status == ExitStatus.ERROR_HTTP_5XX
diff --git a/tests/test_httpie.py b/tests/test_httpie.py
index 74be3a59..2ee647ea 100644
--- a/tests/test_httpie.py
+++ b/tests/test_httpie.py
@@ -1,5 +1,5 @@
 """High-level tests."""
-from utils import TestEnvironment, http, httpbin, HTTP_OK
+from utils import TestEnvironment, http, HTTP_OK
 from fixtures import FILE_PATH, FILE_CONTENT
 import httpie
 
@@ -23,43 +23,43 @@ class TestHTTPie:
         # FIXME: py3 has version in stdout, py2 in stderr
         assert httpie.__version__ == r.stderr.strip() + r.strip()
 
-    def test_GET(self):
-        r = http('GET', httpbin('/get'))
+    def test_GET(self, httpbin):
+        r = http('GET', httpbin.url + '/get')
         assert HTTP_OK in r
 
-    def test_DELETE(self):
-        r = http('DELETE', httpbin('/delete'))
+    def test_DELETE(self, httpbin):
+        r = http('DELETE', httpbin.url + '/delete')
         assert HTTP_OK in r
 
-    def test_PUT(self):
-        r = http('PUT', httpbin('/put'), 'foo=bar')
+    def test_PUT(self, httpbin):
+        r = http('PUT', httpbin.url + '/put', 'foo=bar')
         assert HTTP_OK in r
-        assert r'\"foo\": \"bar\"' in r
+        assert r.json['json']['foo'] == 'bar'
 
-    def test_POST_JSON_data(self):
-        r = http('POST', httpbin('/post'), 'foo=bar')
+    def test_POST_JSON_data(self, httpbin):
+        r = http('POST', httpbin.url + '/post', 'foo=bar')
         assert HTTP_OK in r
-        assert r'\"foo\": \"bar\"' in r
+        assert r.json['json']['foo'] == 'bar'
 
-    def test_POST_form(self):
-        r = http('--form', 'POST', httpbin('/post'), 'foo=bar')
+    def test_POST_form(self, httpbin):
+        r = http('--form', 'POST', httpbin.url + '/post', 'foo=bar')
         assert HTTP_OK in r
         assert '"foo": "bar"' in r
 
-    def test_POST_form_multiple_values(self):
-        r = http('--form', 'POST', httpbin('/post'), 'foo=bar', 'foo=baz')
+    def test_POST_form_multiple_values(self, httpbin):
+        r = http('--form', 'POST', httpbin.url + '/post', 'foo=bar', 'foo=baz')
         assert HTTP_OK in r
         assert r.json['form'] == {'foo': ['bar', 'baz']}
 
-    def test_POST_stdin(self):
+    def test_POST_stdin(self, httpbin):
         with open(FILE_PATH) as f:
             env = TestEnvironment(stdin=f, stdin_isatty=False)
-            r = http('--form', 'POST', httpbin('/post'), env=env)
+            r = http('--form', 'POST', httpbin.url + '/post', env=env)
         assert HTTP_OK in r
         assert FILE_CONTENT in r
 
-    def test_headers(self):
-        r = http('GET', httpbin('/headers'), 'Foo:bar')
+    def test_headers(self, httpbin):
+        r = http('GET', httpbin.url + '/headers', 'Foo:bar')
         assert HTTP_OK in r
         assert '"User-Agent": "HTTPie' in r, r
         assert '"Foo": "bar"' in r
diff --git a/tests/test_output.py b/tests/test_output.py
index a5ac1048..ad2dec04 100644
--- a/tests/test_output.py
+++ b/tests/test_output.py
@@ -2,27 +2,28 @@ import pytest
 
 from httpie import ExitStatus
 from httpie.output.formatters.colors import get_lexer
-from utils import TestEnvironment, http, httpbin, HTTP_OK, COLOR, CRLF
+from utils import TestEnvironment, http, HTTP_OK, COLOR, CRLF
 
 
 class TestVerboseFlag:
-    def test_verbose(self):
-        r = http('--verbose', 'GET', httpbin('/get'), 'test-header:__test__')
+    def test_verbose(self, httpbin):
+        r = http('--verbose',
+                 'GET', httpbin.url + '/get', 'test-header:__test__')
         assert HTTP_OK in r
         assert r.count('__test__') == 2
 
-    def test_verbose_form(self):
+    def test_verbose_form(self, httpbin):
         # https://github.com/jakubroztocil/httpie/issues/53
-        r = http('--verbose', '--form', 'POST', httpbin('/post'),
+        r = http('--verbose', '--form', 'POST', httpbin.url + '/post',
                  'A=B', 'C=D')
         assert HTTP_OK in r
         assert 'A=B&C=D' in r
 
-    def test_verbose_json(self):
-        r = http('--verbose', 'POST', httpbin('/post'), 'foo=bar', 'baz=bar')
+    def test_verbose_json(self, httpbin):
+        r = http('--verbose',
+                 'POST', httpbin.url + '/post', 'foo=bar', 'baz=bar')
         assert HTTP_OK in r
-        assert '"baz": "bar"' in r  # request
-        assert r'\"baz\": \"bar\"' in r  # response
+        assert '"baz": "bar"' in r
 
 
 class TestColors:
@@ -47,45 +48,47 @@ class TestColors:
 class TestPrettyOptions:
     """Test the --pretty flag handling."""
 
-    def test_pretty_enabled_by_default(self):
+    def test_pretty_enabled_by_default(self, httpbin):
         env = TestEnvironment(colors=256)
-        r = http('GET', httpbin('/get'), env=env)
+        r = http('GET', httpbin.url + '/get', env=env)
         assert COLOR in r
 
-    def test_pretty_enabled_by_default_unless_stdout_redirected(self):
-        r = http('GET', httpbin('/get'))
+    def test_pretty_enabled_by_default_unless_stdout_redirected(self, httpbin):
+        r = http('GET', httpbin.url + '/get')
         assert COLOR not in r
 
-    def test_force_pretty(self):
+    def test_force_pretty(self, httpbin):
         env = TestEnvironment(stdout_isatty=False, colors=256)
-        r = http('--pretty=all', 'GET', httpbin('/get'), env=env, )
+        r = http('--pretty=all', 'GET', httpbin.url + '/get', env=env, )
         assert COLOR in r
 
-    def test_force_ugly(self):
-        r = http('--pretty=none', 'GET', httpbin('/get'))
+    def test_force_ugly(self, httpbin):
+        r = http('--pretty=none', 'GET', httpbin.url + '/get')
         assert COLOR not in r
 
-    def test_subtype_based_pygments_lexer_match(self):
+    def test_subtype_based_pygments_lexer_match(self, httpbin):
         """Test that media subtype is used if type/subtype doesn't
         match any lexer.
 
         """
         env = TestEnvironment(colors=256)
-        r = http('--print=B', '--pretty=all', httpbin('/post'),
+        r = http('--print=B', '--pretty=all', httpbin.url + '/post',
                  'Content-Type:text/foo+json', 'a=b', env=env)
         assert COLOR in r
 
-    def test_colors_option(self):
+    def test_colors_option(self, httpbin):
         env = TestEnvironment(colors=256)
-        r = http('--print=B', '--pretty=colors', 'GET', httpbin('/get'), 'a=b',
+        r = http('--print=B', '--pretty=colors',
+                 'GET', httpbin.url + '/get', 'a=b',
                  env=env)
         # Tests that the JSON data isn't formatted.
         assert not r.strip().count('\n')
         assert COLOR in r
 
-    def test_format_option(self):
+    def test_format_option(self, httpbin):
         env = TestEnvironment(colors=256)
-        r = http('--print=B', '--pretty=format', 'GET', httpbin('/get'), 'a=b',
+        r = http('--print=B', '--pretty=format',
+                 'GET', httpbin.url + '/get', 'a=b',
                  env=env)
         # Tests that the JSON data is formatted.
         assert r.strip().count('\n') == 2
@@ -110,24 +113,24 @@ class TestLineEndings:
         assert CRLF not in body
         return body
 
-    def test_CRLF_headers_only(self):
-        r = http('--headers', 'GET', httpbin('/get'))
+    def test_CRLF_headers_only(self, httpbin):
+        r = http('--headers', 'GET', httpbin.url + '/get')
         body = self._validate_crlf(r)
         assert not body, 'Garbage after headers: %r' % r
 
-    def test_CRLF_ugly_response(self):
-        r = http('--pretty=none', 'GET', httpbin('/get'))
+    def test_CRLF_ugly_response(self, httpbin):
+        r = http('--pretty=none', 'GET', httpbin.url + '/get')
         self._validate_crlf(r)
 
-    def test_CRLF_formatted_response(self):
-        r = http('--pretty=format', 'GET', httpbin('/get'))
+    def test_CRLF_formatted_response(self, httpbin):
+        r = http('--pretty=format', 'GET', httpbin.url + '/get')
         assert r.exit_status == ExitStatus.OK
         self._validate_crlf(r)
 
-    def test_CRLF_ugly_request(self):
-        r = http('--pretty=none', '--print=HB', 'GET', httpbin('/get'))
+    def test_CRLF_ugly_request(self, httpbin):
+        r = http('--pretty=none', '--print=HB', 'GET', httpbin.url + '/get')
         self._validate_crlf(r)
 
-    def test_CRLF_formatted_request(self):
-        r = http('--pretty=format', '--print=HB', 'GET', httpbin('/get'))
+    def test_CRLF_formatted_request(self, httpbin):
+        r = http('--pretty=format', '--print=HB', 'GET', httpbin.url + '/get')
         self._validate_crlf(r)
diff --git a/tests/test_regressions.py b/tests/test_regressions.py
index 8c21d1d3..b80fba38 100644
--- a/tests/test_regressions.py
+++ b/tests/test_regressions.py
@@ -4,14 +4,14 @@ import socket
 from utils import http, HTTP_OK
 
 
-def test_Host_header_overwrite():
+def test_Host_header_overwrite(httpbin):
     """
     https://github.com/jakubroztocil/httpie/issues/235
 
     """
     host = 'httpbin.org'
-    url = 'http://{httpbin_ip}/get'.format(
-        httpbin_ip=socket.gethostbyname(host))
-    r = http('--print=hH', url, 'host:{}'.format(host))
+    url = httpbin.url + '/get'
+    r = http('--print=hH', url, 'host:{0}'.format(host))
     assert HTTP_OK in r
     assert r.lower().count('host:') == 1
+    assert 'host: {0}'.format(host) in r
diff --git a/tests/test_sessions.py b/tests/test_sessions.py
index c26e66ed..6d598584 100644
--- a/tests/test_sessions.py
+++ b/tests/test_sessions.py
@@ -3,12 +3,14 @@ import os
 import shutil
 
 from httpie.plugins.builtin import HTTPBasicAuth
-from utils import TestEnvironment, mk_config_dir, http, httpbin, HTTP_OK
+from utils import TestEnvironment, mk_config_dir, http, HTTP_OK, \
+    no_content_type
 from fixtures import UNICODE
 
 
 class SessionTestBase(object):
-    def setup_method(self, method):
+
+    def start_session(self, httpbin):
         """Create and reuse a unique config dir for each test."""
         self.config_dir = mk_config_dir()
 
@@ -33,67 +35,70 @@ class TestSessionFlow(SessionTestBase):
 
     """
 
-    def setup_method(self, method):
+    def start_session(self, httpbin):
         """
         Start a full-blown session with a custom request header,
         authorization, and response cookies.
 
         """
-        super(TestSessionFlow, self).setup_method(method)
+        super(TestSessionFlow, self).start_session(httpbin)
         r1 = http('--follow', '--session=test', '--auth=username:password',
-                  'GET', httpbin('/cookies/set?hello=world'), 'Hello:World',
+                  'GET', httpbin.url + '/cookies/set?hello=world',
+                  'Hello:World',
                   env=self.env())
         assert HTTP_OK in r1
 
-    def test_session_created_and_reused(self):
+    def test_session_created_and_reused(self, httpbin):
+        self.start_session(httpbin)
         # Verify that the session created in setup_method() has been used.
-        r2 = http('--session=test', 'GET', httpbin('/get'), env=self.env())
+        r2 = http('--session=test',
+                  'GET', httpbin.url + '/get', env=self.env())
         assert HTTP_OK in r2
         assert r2.json['headers']['Hello'] == 'World'
         assert r2.json['headers']['Cookie'] == 'hello=world'
         assert 'Basic ' in r2.json['headers']['Authorization']
 
-    def test_session_update(self):
+    def test_session_update(self, httpbin):
+        self.start_session(httpbin)
         # Get a response to a request from the original session.
-        r2 = http('--session=test', 'GET', httpbin('/get'), env=self.env())
+        r2 = http('--session=test', 'GET', httpbin.url + '/get', env=self.env())
         assert HTTP_OK in r2
 
         # Make a request modifying the session data.
         r3 = http('--follow', '--session=test', '--auth=username:password2',
-                  'GET', httpbin('/cookies/set?hello=world2'), 'Hello:World2',
+                  'GET', httpbin.url + '/cookies/set?hello=world2', 'Hello:World2',
                   env=self.env())
         assert HTTP_OK in r3
 
         # Get a response to a request from the updated session.
-        r4 = http('--session=test', 'GET', httpbin('/get'), env=self.env())
+        r4 = http('--session=test', 'GET', httpbin.url + '/get', env=self.env())
         assert HTTP_OK in r4
         assert r4.json['headers']['Hello'] == 'World2'
         assert r4.json['headers']['Cookie'] == 'hello=world2'
         assert (r2.json['headers']['Authorization'] !=
                 r4.json['headers']['Authorization'])
 
-    def test_session_read_only(self):
+    def test_session_read_only(self, httpbin):
+        self.start_session(httpbin)
         # Get a response from the original session.
-        r2 = http('--session=test', 'GET', httpbin('/get'), env=self.env())
+        r2 = http('--session=test', 'GET', httpbin.url + '/get', env=self.env())
         assert HTTP_OK in r2
 
         # Make a request modifying the session data but
         # with --session-read-only.
         r3 = http('--follow', '--session-read-only=test',
                   '--auth=username:password2', 'GET',
-                  httpbin('/cookies/set?hello=world2'), 'Hello:World2',
+                  httpbin.url + '/cookies/set?hello=world2', 'Hello:World2',
                   env=self.env())
         assert HTTP_OK in r3
 
         # Get a response from the updated session.
-        r4 = http('--session=test', 'GET', httpbin('/get'), env=self.env())
+        r4 = http('--session=test', 'GET', httpbin.url + '/get', env=self.env())
         assert HTTP_OK in r4
 
         # Origin can differ on Travis.
         del r2.json['origin'], r4.json['origin']
         # Different for each request.
-        del r2.json['headers']['X-Request-Id']
-        del r4.json['headers']['X-Request-Id']
 
         # Should be the same as before r3.
         assert r2.json == r4.json
@@ -102,51 +107,58 @@ class TestSessionFlow(SessionTestBase):
 class TestSession(SessionTestBase):
     """Stand-alone session tests."""
 
-    def test_session_ignored_header_prefixes(self):
-        r1 = http('--session=test', 'GET', httpbin('/get'),
+    def test_session_ignored_header_prefixes(self, httpbin):
+        self.start_session(httpbin)
+        r1 = http('--session=test', 'GET', httpbin.url + '/get',
                   'Content-Type: text/plain',
                   'If-Unmodified-Since: Sat, 29 Oct 1994 19:43:31 GMT',
                   env=self.env())
         assert HTTP_OK in r1
 
-        r2 = http('--session=test', 'GET', httpbin('/get'), env=self.env())
+        r2 = http('--session=test', 'GET', httpbin.url + '/get', env=self.env())
         assert HTTP_OK in r2
-        assert 'Content-Type' not in r2.json['headers']
+        assert no_content_type(r2.json['headers'])
         assert 'If-Unmodified-Since' not in r2.json['headers']
 
-    def test_session_by_path(self):
+    def test_session_by_path(self, httpbin):
+        self.start_session(httpbin)
         session_path = os.path.join(self.config_dir, 'session-by-path.json')
-        r1 = http('--session=' + session_path, 'GET', httpbin('/get'),
+        r1 = http('--session=' + session_path, 'GET', httpbin.url + '/get',
                   'Foo:Bar', env=self.env())
         assert HTTP_OK in r1
 
-        r2 = http('--session=' + session_path, 'GET', httpbin('/get'),
+        r2 = http('--session=' + session_path, 'GET', httpbin.url + '/get',
                   env=self.env())
         assert HTTP_OK in r2
         assert r2.json['headers']['Foo'] == 'Bar'
 
-    def test_session_unicode(self):
-        r1 = http('--session=test', '--auth', u'test:' + UNICODE,
-                  'GET', httpbin('/get'),
-                  u'Test:%s' % UNICODE,
+    def test_session_unicode(self, httpbin):
+        self.start_session(httpbin)
+
+        r1 = http('--session=test', u'--auth=test:' + UNICODE,
+                  'GET', httpbin.url + '/get', u'Test:%s' % UNICODE,
                   env=self.env())
         assert HTTP_OK in r1
 
         r2 = http('--session=test', '--verbose', 'GET',
-                  httpbin('/get'), env=self.env())
+                  httpbin.url + '/get', env=self.env())
         assert HTTP_OK in r2
+
+        # FIXME: Authorization *sometimes* is not present on Python3
         assert (r2.json['headers']['Authorization']
                 == HTTPBasicAuth.make_header(u'test', UNICODE))
         # httpbin doesn't interpret utf8 headers
         assert UNICODE in r2
 
-    def test_session_default_header_value_overwritten(self):
+    def test_session_default_header_value_overwritten(self, httpbin):
+        self.start_session(httpbin)
         # https://github.com/jakubroztocil/httpie/issues/180
-        r1 = http('--session=test', httpbin('/headers'), 'User-Agent:custom',
+        r1 = http('--session=test',
+                  httpbin.url + '/headers', 'User-Agent:custom',
                   env=self.env())
         assert HTTP_OK in r1
         assert r1.json['headers']['User-Agent'] == 'custom'
 
-        r2 = http('--session=test', httpbin('/headers'), env=self.env())
+        r2 = http('--session=test', httpbin.url + '/headers', env=self.env())
         assert HTTP_OK in r2
         assert r2.json['headers']['User-Agent'] == 'custom'
diff --git a/tests/test_stream.py b/tests/test_stream.py
index d21e98ef..9e967519 100644
--- a/tests/test_stream.py
+++ b/tests/test_stream.py
@@ -2,7 +2,7 @@ import pytest
 
 from httpie.compat import is_windows
 from httpie.output.streams import BINARY_SUPPRESSED_NOTICE
-from utils import http, httpbin, TestEnvironment
+from utils import http, TestEnvironment
 from fixtures import BIN_FILE_CONTENT, BIN_FILE_PATH
 
 
@@ -11,26 +11,26 @@ class TestStream:
 
     @pytest.mark.skipif(is_windows,
                         reason='Pretty redirect not supported under Windows')
-    def test_pretty_redirected_stream(self):
+    def test_pretty_redirected_stream(self, httpbin):
         """Test that --stream works with prettified redirected output."""
         with open(BIN_FILE_PATH, 'rb') as f:
             env = TestEnvironment(colors=256, stdin=f,
                                   stdin_isatty=False,
                                   stdout_isatty=False)
             r = http('--verbose', '--pretty=all', '--stream', 'GET',
-                     httpbin('/get'), env=env)
+                     httpbin.url + '/get', env=env)
         assert BINARY_SUPPRESSED_NOTICE.decode() in r
 
-    def test_encoded_stream(self):
+    def test_encoded_stream(self, httpbin):
         """Test that --stream works with non-prettified
         redirected terminal output."""
         with open(BIN_FILE_PATH, 'rb') as f:
             env = TestEnvironment(stdin=f, stdin_isatty=False)
             r = http('--pretty=none', '--stream', '--verbose', 'GET',
-                     httpbin('/get'), env=env)
+                     httpbin.url + '/get', env=env)
         assert BINARY_SUPPRESSED_NOTICE.decode() in r
 
-    def test_redirected_stream(self):
+    def test_redirected_stream(self, httpbin):
         """Test that --stream works with non-prettified
         redirected terminal output."""
         with open(BIN_FILE_PATH, 'rb') as f:
@@ -38,5 +38,5 @@ class TestStream:
                                   stdin_isatty=False,
                                   stdin=f)
             r = http('--pretty=none', '--stream', '--verbose', 'GET',
-                     httpbin('/get'), env=env)
+                     httpbin.url + '/get', env=env)
         assert BIN_FILE_CONTENT in r
diff --git a/tests/test_unicode.py b/tests/test_unicode.py
index 0932c9d4..abcd9ebd 100644
--- a/tests/test_unicode.py
+++ b/tests/test_unicode.py
@@ -3,85 +3,85 @@
 Various unicode handling related tests.
 
 """
-from utils import http, httpbin, HTTP_OK
+from utils import http, HTTP_OK
 from fixtures import UNICODE
 
 
 class TestUnicode:
 
-    def test_unicode_headers(self):
+    def test_unicode_headers(self, httpbin):
         # httpbin doesn't interpret utf8 headers
-        r = http(httpbin('/headers'), u'Test:%s' % UNICODE)
+        r = http(httpbin.url + '/headers', u'Test:%s' % UNICODE)
         assert HTTP_OK in r
 
-    def test_unicode_headers_verbose(self):
+    def test_unicode_headers_verbose(self, httpbin):
         # httpbin doesn't interpret utf8 headers
-        r = http('--verbose', httpbin('/headers'), u'Test:%s' % UNICODE)
+        r = http('--verbose', httpbin.url + '/headers', u'Test:%s' % UNICODE)
         assert HTTP_OK in r
         assert UNICODE in r
 
-    def test_unicode_form_item(self):
-        r = http('--form', 'POST', httpbin('/post'), u'test=%s' % UNICODE)
+    def test_unicode_form_item(self, httpbin):
+        r = http('--form', 'POST', httpbin.url + '/post', u'test=%s' % UNICODE)
         assert HTTP_OK in r
         assert r.json['form'] == {'test': UNICODE}
 
-    def test_unicode_form_item_verbose(self):
+    def test_unicode_form_item_verbose(self, httpbin):
         r = http('--verbose', '--form',
-                 'POST', httpbin('/post'), u'test=%s' % UNICODE)
+                 'POST', httpbin.url + '/post', u'test=%s' % UNICODE)
         assert HTTP_OK in r
         assert UNICODE in r
 
-    def test_unicode_json_item(self):
-        r = http('--json', 'POST', httpbin('/post'), u'test=%s' % UNICODE)
+    def test_unicode_json_item(self, httpbin):
+        r = http('--json', 'POST', httpbin.url + '/post', u'test=%s' % UNICODE)
         assert HTTP_OK in r
         assert r.json['json'] == {'test': UNICODE}
 
-    def test_unicode_json_item_verbose(self):
+    def test_unicode_json_item_verbose(self, httpbin):
         r = http('--verbose', '--json',
-                 'POST', httpbin('/post'), u'test=%s' % UNICODE)
+                 'POST', httpbin.url + '/post', u'test=%s' % UNICODE)
         assert HTTP_OK in r
         assert UNICODE in r
 
-    def test_unicode_raw_json_item(self):
-        r = http('--json', 'POST', httpbin('/post'),
+    def test_unicode_raw_json_item(self, httpbin):
+        r = http('--json', 'POST', httpbin.url + '/post',
                  u'test:={ "%s" : [ "%s" ] }' % (UNICODE, UNICODE))
         assert HTTP_OK in r
         assert r.json['json'] == {'test': {UNICODE: [UNICODE]}}
 
-    def test_unicode_raw_json_item_verbose(self):
-        r = http('--json', 'POST', httpbin('/post'),
+    def test_unicode_raw_json_item_verbose(self, httpbin):
+        r = http('--json', 'POST', httpbin.url + '/post',
                  u'test:={ "%s" : [ "%s" ] }' % (UNICODE, UNICODE))
         assert HTTP_OK in r
         assert r.json['json'] == {'test': {UNICODE: [UNICODE]}}
 
-    def test_unicode_url_query_arg_item(self):
-        r = http(httpbin('/get'), u'test==%s' % UNICODE)
+    def test_unicode_url_query_arg_item(self, httpbin):
+        r = http(httpbin.url + '/get', u'test==%s' % UNICODE)
         assert HTTP_OK in r
         assert r.json['args'] == {'test': UNICODE}, r
 
-    def test_unicode_url_query_arg_item_verbose(self):
-        r = http('--verbose', httpbin('/get'), u'test==%s' % UNICODE)
+    def test_unicode_url_query_arg_item_verbose(self, httpbin):
+        r = http('--verbose', httpbin.url + '/get', u'test==%s' % UNICODE)
         assert HTTP_OK in r
         assert UNICODE in r
 
-    def test_unicode_url(self):
-        r = http(httpbin(u'/get?test=' + UNICODE))
+    def test_unicode_url(self, httpbin):
+        r = http(httpbin.url + u'/get?test=' + UNICODE)
         assert HTTP_OK in r
         assert r.json['args'] == {'test': UNICODE}
 
     # def test_unicode_url_verbose(self):
-    #     r = http(httpbin('--verbose', u'/get?test=' + UNICODE))
+    #     r = http(httpbin.url + '--verbose', u'/get?test=' + UNICODE)
     #     assert HTTP_OK in r
 
-    def test_unicode_basic_auth(self):
+    def test_unicode_basic_auth(self, httpbin):
         # it doesn't really authenticate us because httpbin
         # doesn't interpret the utf8-encoded auth
         http('--verbose', '--auth', u'test:%s' % UNICODE,
-             httpbin(u'/basic-auth/test/' + UNICODE))
+             httpbin.url + u'/basic-auth/test/' + UNICODE)
 
-    def test_unicode_digest_auth(self):
+    def test_unicode_digest_auth(self, httpbin):
         # it doesn't really authenticate us because httpbin
         # doesn't interpret the utf8-encoded auth
         http('--auth-type=digest',
              '--auth', u'test:%s' % UNICODE,
-             httpbin(u'/digest-auth/auth/test/' + UNICODE))
+             httpbin.url + u'/digest-auth/auth/test/' + UNICODE)
diff --git a/tests/test_uploads.py b/tests/test_uploads.py
index 073b98c9..f725c62d 100644
--- a/tests/test_uploads.py
+++ b/tests/test_uploads.py
@@ -3,23 +3,25 @@ import os
 import pytest
 
 from httpie.input import ParseError
-from utils import TestEnvironment, http, httpbin, HTTP_OK
+from utils import TestEnvironment, http, HTTP_OK
 from fixtures import FILE_PATH_ARG, FILE_PATH, FILE_CONTENT
 
 
 class TestMultipartFormDataFileUpload:
-    def test_non_existent_file_raises_parse_error(self):
-        with pytest.raises(ParseError):
-            http('--form', 'POST', httpbin('/post'), 'foo@/__does_not_exist__')
 
-    def test_upload_ok(self):
-        r = http('--form', '--verbose', 'POST', httpbin('/post'),
+    def test_non_existent_file_raises_parse_error(self, httpbin):
+        with pytest.raises(ParseError):
+            http('--form',
+                 'POST', httpbin.url + '/post', 'foo@/__does_not_exist__')
+
+    def test_upload_ok(self, httpbin):
+        r = http('--form', '--verbose', 'POST', httpbin.url + '/post',
                  'test-file@%s' % FILE_PATH_ARG, 'foo=bar')
         assert HTTP_OK in r
         assert 'Content-Disposition: form-data; name="foo"' in r
         assert 'Content-Disposition: form-data; name="test-file";' \
                ' filename="%s"' % os.path.basename(FILE_PATH) in r
-        assert r.count(FILE_CONTENT) == 2
+        assert FILE_CONTENT in r
         assert '"foo": "bar"' in r
 
 
@@ -29,27 +31,32 @@ class TestRequestBodyFromFilePath:
 
     """
 
-    def test_request_body_from_file_by_path(self):
-        r = http('--verbose', 'POST', httpbin('/post'), '@' + FILE_PATH_ARG)
+    def test_request_body_from_file_by_path(self, httpbin):
+        r = http('--verbose',
+                 'POST', httpbin.url + '/post', '@' + FILE_PATH_ARG)
         assert HTTP_OK in r
         assert FILE_CONTENT in r, r
         assert '"Content-Type": "text/plain"' in r
 
-    def test_request_body_from_file_by_path_with_explicit_content_type(self):
-        r = http('POST', httpbin('/post'), '@' + FILE_PATH_ARG,
-                 'Content-Type:x-foo/bar')
+    def test_request_body_from_file_by_path_with_explicit_content_type(
+            self, httpbin):
+        r = http('--verbose',
+                 'POST', httpbin.url + '/post', '@' + FILE_PATH_ARG,
+                 'Content-Type:text/plain; charset=utf8')
         assert HTTP_OK in r
         assert FILE_CONTENT in r
-        assert '"Content-Type": "x-foo/bar"' in r
+        assert 'Content-Type: text/plain; charset=utf8' in r
 
-    def test_request_body_from_file_by_path_no_field_name_allowed(self):
+    def test_request_body_from_file_by_path_no_field_name_allowed(
+            self, httpbin):
         env = TestEnvironment(stdin_isatty=True)
-        r = http('POST', httpbin('/post'), 'field-name@' + FILE_PATH_ARG,
+        r = http('POST', httpbin.url + '/post', 'field-name@' + FILE_PATH_ARG,
                  env=env, error_exit_ok=True)
         assert 'perhaps you meant --form?' in r.stderr
 
-    def test_request_body_from_file_by_path_no_data_items_allowed(self):
+    def test_request_body_from_file_by_path_no_data_items_allowed(
+            self, httpbin):
         env = TestEnvironment(stdin_isatty=False)
-        r = http('POST', httpbin('/post'), '@' + FILE_PATH_ARG, 'foo=bar',
+        r = http('POST', httpbin.url + '/post', '@' + FILE_PATH_ARG, 'foo=bar',
                  env=env, error_exit_ok=True)
         assert 'cannot be mixed' in r.stderr
diff --git a/tests/test_windows.py b/tests/test_windows.py
index ad15fe52..91669f5c 100644
--- a/tests/test_windows.py
+++ b/tests/test_windows.py
@@ -4,7 +4,7 @@ import tempfile
 import pytest
 from httpie.context import Environment
 
-from utils import TestEnvironment, http, httpbin
+from utils import TestEnvironment, http
 from httpie.compat import is_windows
 
 
@@ -13,17 +13,17 @@ class TestWindowsOnly:
 
     @pytest.mark.skipif(True,
                         reason='this test for some reason kills the process')
-    def test_windows_colorized_output(self):
+    def test_windows_colorized_output(self, httpbin):
         # Spits out the colorized output.
-        http(httpbin('/get'), env=Environment())
+        http(httpbin.url + '/get', env=Environment())
 
 
 class TestFakeWindows:
-    def test_output_file_pretty_not_allowed_on_windows(self):
+    def test_output_file_pretty_not_allowed_on_windows(self, httpbin):
         env = TestEnvironment(is_windows=True)
         output_file = os.path.join(
             tempfile.gettempdir(), '__httpie_test_output__')
         r = http('--output', output_file,
-                 '--pretty=all', 'GET', httpbin('/get'),
+                 '--pretty=all', 'GET', httpbin.url + '/get',
                  env=env, error_exit_ok=True)
         assert 'Only terminal output can be colorized on Windows' in r.stderr
diff --git a/tests/utils.py b/tests/utils.py
index 1a9e5eb6..aad27395 100644
--- a/tests/utils.py
+++ b/tests/utils.py
@@ -20,7 +20,7 @@ TESTS_ROOT = os.path.abspath(os.path.dirname(__file__))
 
 CRLF = '\r\n'
 COLOR = '\x1b['
-HTTP_OK = 'HTTP/1.1 200'
+HTTP_OK = '200 OK'
 HTTP_OK_COLOR = (
     'HTTP\x1b[39m\x1b[38;5;245m/\x1b[39m\x1b'
     '[38;5;37m1.1\x1b[39m\x1b[38;5;245m \x1b[39m\x1b[38;5;37m200'
@@ -28,22 +28,19 @@ HTTP_OK_COLOR = (
 )
 
 
-def httpbin(path, auth=None,
-            base=os.environ.get('HTTPBIN_URL', 'http://httpbin.org')):
-    """
-    Return a fully-qualified httpbin URL for `path`.
+def no_content_type(headers):
+    return (
+        'Content-Type' not in headers
+        # We need to do also this because of this issue:
+        # <https://github.com/kevin1024/pytest-httpbin/issues/5>
+        # TODO: remove this function once the issue is if fixed
+        or headers['Content-Type'] == 'text/plain'
+    )
 
-    >>> httpbin('/get')
-    'http://httpbin.org/get'
 
-    >>> httpbin('/get', auth='user:password')
-    'http://user:password@httpbin.org/get'
-
-    """
-    if auth:
-        proto, rest = base.split('://', 1)
-        base = proto + '://' + auth + '@' + rest
-    return base.rstrip('/') + path
+def add_auth(url, auth):
+    proto, rest = url.split('://', 1)
+    return proto + '://' + auth + '@' + rest
 
 
 class TestEnvironment(Environment):
@@ -104,7 +101,7 @@ def http(*args, **kwargs):
 
     $ http --auth=user:password GET httpbin.org/basic-auth/user/password
 
-        >>> r = http('-a', 'user:pw', httpbin('/basic-auth/user/pw'))
+        >>> r = http('-a', 'user:pw', 'httpbin.org/basic-auth/user/pw')
         >>> type(r) == StrCLIResponse
         True
         >>> r.exit_status
diff --git a/tox.ini b/tox.ini
index 3e37c178..d140537a 100644
--- a/tox.ini
+++ b/tox.ini
@@ -13,6 +13,7 @@ envlist = py26, py27, py34, pypy
 deps =
     pytest
     pytest-xdist
+    pytest-httpbin
 
 commands =
     py.test -n 8 --doctest-modules --basetemp={envtmpdir} {posargs:./tests ./httpie}