Attempt to fix broken build

PyGitUp/gitup.py

@@ -97,7 +97,7 @@ def get_git_dir():
     if os.path.isdir(git_dir):
         return abspath
     else:
-        return execute('git rev-parse --show-toplevel')
+        return execute(['git', 'rev-parse', '--show-toplevel'])
 
 
 class GitUp(object):

PyGitUp/utils.py

@@ -22,15 +22,18 @@ def uniq(seq):
 
 def execute(cmd):
     """ Execute a command and return it's output. """
-    try:
-        lines = subprocess.check_output(cmd).splitlines()
-    except subprocess.CalledProcessError:
+    process = subprocess.Popen(cmd, stdout=subprocess.PIPE)
+    output, _ = process.communicate()
+    retcode = process.poll()
+
+    if retcode:
         return None
+
+    lines = output.splitlines()
+    if lines:
+        return lines[0].strip()
     else:
-        if lines:
-            return lines[0].strip()
-        else:
-            return None
+        return None
 
 
 def decode(s):

tests/test_git_not_in_path.py

@@ -23,10 +23,12 @@ def test_not_a_git_repo():
     environ = os.environ.copy()
     os.environ['PATH'] = ''
 
-    with assert_raises(GitError) as e:
-        from PyGitUp.gitup import GitUp
-        GitUp(testing=True)
+    try:
+        with assert_raises(GitError) as e:
+            from PyGitUp.gitup import GitUp
+            GitUp(testing=True)
 
-    assert e.exception.message == "The git executable could not be found"
+        assert e.exception.message == "The git executable could not be found"
 
-    os.environ.update(environ)
+    finally:
+        os.environ.update(environ)