diff --git a/.gitignore b/.gitignore
index 9c5d32a0..c5856256 100644
--- a/.gitignore
+++ b/.gitignore
@@ -2,6 +2,7 @@ dist
 httpie.egg-info
 build
 *.pyc
+*.egg
 .tox
 README.html
 .coverage
diff --git a/httpie/utils.py b/httpie/utils.py
index 37ac745d..703a101c 100644
--- a/httpie/utils.py
+++ b/httpie/utils.py
@@ -10,20 +10,20 @@ def humanize_bytes(n, precision=2):
     Assumes `from __future__ import division`.
 
     >>> humanize_bytes(1)
-    '1 byte'
-    >>> humanize_bytes(1024)
+    '1 B'
+    >>> humanize_bytes(1024, precision=1)
     '1.0 kB'
-    >>> humanize_bytes(1024 * 123)
+    >>> humanize_bytes(1024 * 123, precision=1)
     '123.0 kB'
-    >>> humanize_bytes(1024 * 12342)
+    >>> humanize_bytes(1024 * 12342, precision=1)
     '12.1 MB'
-    >>> humanize_bytes(1024 * 12342, 2)
+    >>> humanize_bytes(1024 * 12342, precision=2)
     '12.05 MB'
-    >>> humanize_bytes(1024 * 1234, 2)
+    >>> humanize_bytes(1024 * 1234, precision=2)
     '1.21 MB'
-    >>> humanize_bytes(1024 * 1234 * 1111, 2)
+    >>> humanize_bytes(1024 * 1234 * 1111, precision=2)
     '1.31 GB'
-    >>> humanize_bytes(1024 * 1234 * 1111, 1)
+    >>> humanize_bytes(1024 * 1234 * 1111, precision=1)
     '1.3 GB'
 
     """
diff --git a/requirements-dev.txt b/requirements-dev.txt
index c3b33209..f5698407 100644
--- a/requirements-dev.txt
+++ b/requirements-dev.txt
@@ -1,3 +1,4 @@
 tox
+pytest
 git+git://github.com/kennethreitz/httpbin.git@7c96875e87a448f08fb1981e85eb79e77d592d98
 docutils
diff --git a/setup.py b/setup.py
index c94cc5d8..0c479d1c 100644
--- a/setup.py
+++ b/setup.py
@@ -1,16 +1,32 @@
-import os
 import sys
 import codecs
 from setuptools import setup
+from setuptools.command.test import test as TestCommand
+
 import httpie
 
 
-if sys.argv[-1] == 'test':
-    status = os.system('python tests/tests.py')
-    sys.exit(1 if status > 127 else status)
+class PyTest(TestCommand):
+    def finalize_options(self):
+        TestCommand.finalize_options(self)
+        self.test_suite = True
+        self.test_args = [
+            '--doctest-modules',
+            './httpie', './tests'
+        ]
+        self.test_suite = True
+
+    def run_tests(self):
+        import pytest
+        sys.exit(pytest.main(self.test_args))
 
 
-requirements = [
+tests_require = [
+    'pytest',
+]
+
+
+install_requires = [
     'requests>=2.0.0',
     'Pygments>=1.5'
 ]
@@ -18,11 +34,11 @@ try:
     #noinspection PyUnresolvedReferences
     import argparse
 except ImportError:
-    requirements.append('argparse>=1.2.1')
+    install_requires.append('argparse>=1.2.1')
 
 if 'win32' in str(sys.platform).lower():
     # Terminal colors for Windows
-    requirements.append('colorama>=0.2.4')
+    install_requires.append('colorama>=0.2.4')
 
 
 def long_description():
@@ -46,7 +62,11 @@ setup(
             'http = httpie.__main__:main',
         ],
     },
-    install_requires=requirements,
+    install_requires=install_requires,
+    cmdclass={'test': PyTest},
+    tests_require=tests_require,
+    extras_require={'tests': tests_require},
+
     classifiers=[
         'Development Status :: 5 - Production/Stable',
         'Programming Language :: Python',
diff --git a/tests/__init__.py b/tests/__init__.py
index c9984e92..9782b755 100644
--- a/tests/__init__.py
+++ b/tests/__init__.py
@@ -5,15 +5,13 @@ import json
 import shutil
 import tempfile
 
-# HACK: Prepend ../ to PYTHONPATH so that we can import httpie form there.
-TESTS_ROOT = os.path.abspath(os.path.dirname(__file__))
-sys.path.insert(0, os.path.realpath(os.path.join(TESTS_ROOT, '..')))
 from httpie import ExitStatus
 from httpie.models import Environment
 from httpie.core import main
 from httpie.compat import bytes, str
 
 
+TESTS_ROOT = os.path.abspath(os.path.dirname(__file__))
 HTTPBIN_URL = os.environ.get('HTTPBIN_URL',
                              'http://httpbin.org').rstrip('/')
 
diff --git a/tests/test_downloads.py b/tests/test_downloads.py
index a82b1d6e..7661cdc1 100644
--- a/tests/test_downloads.py
+++ b/tests/test_downloads.py
@@ -2,6 +2,7 @@ import os
 import time
 from unittest import TestCase
 
+import pytest
 from requests.structures import CaseInsensitiveDict
 
 from httpie.compat import urlopen
@@ -32,22 +33,22 @@ class DownloadUtilsTest(TestCase):
         assert parse('bytes 100-199/*', 100) == 200
 
         # missing
-        self.assertRaises(ContentRangeError, parse, None, 100)
+        pytest.raises(ContentRangeError, parse, None, 100)
 
         # syntax error
-        self.assertRaises(ContentRangeError, parse, 'beers 100-199/*', 100)
+        pytest.raises(ContentRangeError, parse, 'beers 100-199/*', 100)
 
         # unexpected range
-        self.assertRaises(ContentRangeError, parse, 'bytes 100-199/*', 99)
+        pytest.raises(ContentRangeError, parse, 'bytes 100-199/*', 99)
 
         # invalid instance-length
-        self.assertRaises(ContentRangeError, parse, 'bytes 100-199/199', 100)
+        pytest.raises(ContentRangeError, parse, 'bytes 100-199/199', 100)
 
         # invalid byte-range-resp-spec
-        self.assertRaises(ContentRangeError, parse, 'bytes 100-99/199', 100)
+        pytest.raises(ContentRangeError, parse, 'bytes 100-99/199', 100)
 
         # invalid byte-range-resp-spec
-        self.assertRaises(ContentRangeError, parse, 'bytes 100-100/*', 100)
+        pytest.raises(ContentRangeError, parse, 'bytes 100-100/*', 100)
 
     def test_Content_Disposition_parsing(self):
         parse = filename_from_content_disposition
diff --git a/tests/test_output.py b/tests/test_output.py
index 7b091950..b5ebd6e8 100644
--- a/tests/test_output.py
+++ b/tests/test_output.py
@@ -17,9 +17,10 @@ class VerboseFlagTest(TestCase):
     def test_verbose_form(self):
         # https://github.com/jkbr/httpie/issues/53
         r = http('--verbose', '--form', 'POST', httpbin('/post'),
-                 'foo=bar', 'baz=bar')
+                 'A=B', 'C=D')
         assert HTTP_OK in r
-        assert 'foo=bar&baz=bar' in r
+        # Python 2.6 has no ordered dict, so we test for both orders here.
+        assert 'A=B&C=D' in r or 'C=D&A=B', r
 
     def test_verbose_json(self):
         r = http('--verbose', 'POST', httpbin('/post'), 'foo=bar', 'baz=bar')
diff --git a/tests/test_uploads.py b/tests/test_uploads.py
index b81c60dd..0a1df331 100644
--- a/tests/test_uploads.py
+++ b/tests/test_uploads.py
@@ -1,6 +1,8 @@
 import os
 from unittest import TestCase
 
+import pytest
+
 from httpie.input import ParseError
 from tests import TestEnvironment, http, httpbin, HTTP_OK
 from tests.fixtures import FILE_PATH_ARG, FILE_PATH, FILE_CONTENT
@@ -8,7 +10,7 @@ from tests.fixtures import FILE_PATH_ARG, FILE_PATH, FILE_CONTENT
 
 class MultipartFormDataFileUploadTest(TestCase):
     def test_non_existent_file_raises_parse_error(self):
-        with self.assertRaises(ParseError):
+        with pytest.raises(ParseError):
             http('--form', 'POST', httpbin('/post'), 'foo@/__does_not_exist__')
 
     def test_upload_ok(self):
diff --git a/tox.ini b/tox.ini
index 65461037..7ce95a13 100644
--- a/tox.ini
+++ b/tox.ini
@@ -4,7 +4,7 @@
 # and then run "tox" from this directory.
 
 [tox]
-envlist = py26, py27, py33, pypy
+envlist = py26, py27, py34, pypy
 
 [testenv]
 commands = {envpython} setup.py test