diff --git a/.gitignore b/.gitignore
index 8bb23235..7e27b2c9 100644
--- a/.gitignore
+++ b/.gitignore
@@ -3,3 +3,4 @@ dist
 git_review.egg-info
 MANIFEST
 .tox
+requirements.txt
diff --git a/requirements.txt b/requirements.txt
deleted file mode 100644
index f3fd43fd..00000000
--- a/requirements.txt
+++ /dev/null
@@ -1,2 +0,0 @@
-argparse==1.2.1
-wsgiref==0.1.2
diff --git a/setup.py b/setup.py
index c0bdad15..258c3635 100755
--- a/setup.py
+++ b/setup.py
@@ -24,6 +24,7 @@ __name__ = "not-main"
 exec(open("git-review", "r"))
 __name__ = savename
 
+
 class git_review_install(install):
     # Force single-version-externally-managed
     # This puts the manpage in the right location (instead of buried
@@ -33,28 +34,40 @@ class git_review_install(install):
 
 git_review_cmdclass = {'install': git_review_install}
 
+
 def parse_requirements(file_name):
     requirements = []
-    for line in open(file_name, 'r').read().split('\n'):
-        if re.match(r'(\s*#)|(\s*$)', line):
-            continue
-        if re.match(r'\s*-e\s+', line):
-            requirements.append(re.sub(r'\s*-e\s+.*#egg=(.*)$', r'\1', line))
-        elif re.match(r'\s*-f\s+', line):
-            pass
-        else:
-            requirements.append(line)
+    if os.path.exists(file_name):
+        for line in open(file_name, 'r').read().split('\n'):
+            if re.match(r'(\s*#)|(\s*$)', line):
+                continue
+            if re.match(r'\s*-e\s+', line):
+                requirements.append(re.sub(r'\s*-e\s+.*#egg=(.*)$', r'\1',
+                                    line))
+            elif re.match(r'\s*-f\s+', line):
+                pass
+            else:
+                requirements.append(line)
 
     return requirements
 
+
 def parse_dependency_links(file_name):
     dependency_links = []
-    for line in open(file_name, 'r').read().split('\n'):
-        if re.match(r'\s*-[ef]\s+', line):
-            dependency_links.append(re.sub(r'\s*-[ef]\s+', '', line))
-
+    if os.path.exists(file_name):
+        for line in open(file_name, 'r').read().split('\n'):
+            if re.match(r'\s*-[ef]\s+', line):
+                dependency_links.append(re.sub(r'\s*-[ef]\s+', '', line))
     return dependency_links
 
+venv = os.environ.get('VIRTUAL_ENV', None)
+if venv is not None:
+    with open("requirements.txt", "w") as req_file:
+        output = subprocess.Popen(["pip", "-E", venv, "freeze", "-l"],
+                                  stdout=subprocess.PIPE)
+        requirements = output.communicate()[0].strip()
+        req_file.write(requirements)
+
 setup(
     name='git-review',
     version=version,
diff --git a/tox.ini b/tox.ini
index af9e1009..e7275f22 100644
--- a/tox.ini
+++ b/tox.ini
@@ -2,7 +2,10 @@
 envlist = py26,py27
 
 [testenv]
-#deps = -r{toxinidir}/tools/pip-requires
+setenv = VIRTUAL_ENV={envdir}
 deps = pep8
-commands = pep8 git-review
+       argparse
+commands = pep8  --show-source setup.py git-review
 
+[testenv:sdist]
+commands = python setup.py sdist {posargs}