diff --git a/src/wormhole/scripts/send_common.py b/src/wormhole/scripts/send_common.py
index 260e201..20f2b63 100644
--- a/src/wormhole/scripts/send_common.py
+++ b/src/wormhole/scripts/send_common.py
@@ -37,8 +37,6 @@ def build_phase1_data(args):
     if not os.path.exists(what):
         raise TransferError("Cannot send: no file/directory named '%s'" %
                             args.what)
-
-    what = os.path.join(args.cwd, args.what)
     basename = os.path.basename(what)
 
     if os.path.isfile(what):
@@ -88,4 +86,4 @@ def build_phase1_data(args):
               % (filesize, basename), file=args.stdout)
         return phase1, fd_to_send
 
-    raise TypeError("'%s' is neither file nor directory" % what)
+    raise TypeError("'%s' is neither file nor directory" % args.what)
diff --git a/src/wormhole/test/test_scripts.py b/src/wormhole/test/test_scripts.py
index 3834c8f..1e9767c 100644
--- a/src/wormhole/test/test_scripts.py
+++ b/src/wormhole/test/test_scripts.py
@@ -1,4 +1,4 @@
-import os, sys, re, io
+import os, sys, re, io, zipfile
 from twisted.trial import unittest
 from twisted.python import procutils, log
 from twisted.internet.utils import getProcessOutputAndValue
@@ -7,6 +7,129 @@ from twisted.internet.threads import deferToThread
 from .. import __version__
 from .common import ServerBase
 from ..scripts import runner, cmd_send_blocking, cmd_receive
+from ..scripts.send_common import build_phase1_data
+from ..errors import TransferError
+
+class Phase1Data(unittest.TestCase):
+    def test_text(self):
+        message = "blah blah blah ponies"
+
+        send_args = [ "send", "--text", message ]
+        args = runner.parser.parse_args(send_args)
+        args.cwd = os.getcwd()
+        args.stdout = io.StringIO()
+        args.stderr = io.StringIO()
+
+        d, fd_to_send = build_phase1_data(args)
+
+        self.assertIn("message", d)
+        self.assertNotIn("file", d)
+        self.assertNotIn("directory", d)
+        self.assertEqual(d["message"], message)
+        self.assertEqual(fd_to_send, None)
+
+    def test_file(self):
+        filename = "my file"
+        message = b"yay ponies\n"
+        send_dir = self.mktemp()
+        os.mkdir(send_dir)
+        abs_filename = os.path.join(send_dir, filename)
+        with open(abs_filename, "wb") as f:
+            f.write(message)
+
+        send_args = [ "send", filename ]
+        args = runner.parser.parse_args(send_args)
+        args.cwd = send_dir
+        args.stdout = io.StringIO()
+        args.stderr = io.StringIO()
+
+        d, fd_to_send = build_phase1_data(args)
+
+        self.assertNotIn("message", d)
+        self.assertIn("file", d)
+        self.assertNotIn("directory", d)
+        self.assertEqual(d["file"]["filesize"], len(message))
+        self.assertEqual(d["file"]["filename"], filename)
+        self.assertEqual(fd_to_send.tell(), 0)
+        self.assertEqual(fd_to_send.read(), message)
+
+    def test_missing_file(self):
+        filename = "missing"
+        send_dir = self.mktemp()
+        os.mkdir(send_dir)
+
+        send_args = [ "send", filename ]
+        args = runner.parser.parse_args(send_args)
+        args.cwd = send_dir
+        args.stdout = io.StringIO()
+        args.stderr = io.StringIO()
+
+        e = self.assertRaises(TransferError, build_phase1_data, args)
+        self.assertEqual(str(e),
+                         "Cannot send: no file/directory named '%s'" % filename)
+
+    def test_directory(self):
+        parent_dir = self.mktemp()
+        os.mkdir(parent_dir)
+        send_dir = "dirname"
+        os.mkdir(os.path.join(parent_dir, send_dir))
+        ponies = [str(i) for i in range(5)]
+        for p in ponies:
+            with open(os.path.join(parent_dir, send_dir, p), "wb") as f:
+                f.write(("%s ponies\n" % p).encode("ascii"))
+
+        send_args = [ "send", send_dir ]
+        args = runner.parser.parse_args(send_args)
+        args.cwd = parent_dir
+        args.stdout = io.StringIO()
+        args.stderr = io.StringIO()
+
+        d, fd_to_send = build_phase1_data(args)
+
+        self.assertNotIn("message", d)
+        self.assertNotIn("file", d)
+        self.assertIn("directory", d)
+        self.assertEqual(d["directory"]["dirname"], send_dir)
+        self.assertEqual(d["directory"]["mode"], "zipfile/deflated")
+        self.assertEqual(d["directory"]["numfiles"], 5)
+        self.assertIn("numbytes", d["directory"])
+        self.assertIsInstance(d["directory"]["numbytes"], type(123))
+
+        self.assertEqual(fd_to_send.tell(), 0)
+        zdata = fd_to_send.read()
+        self.assertEqual(len(zdata), d["directory"]["zipsize"])
+        fd_to_send.seek(0, 0)
+        with zipfile.ZipFile(fd_to_send, "r", zipfile.ZIP_DEFLATED) as zf:
+            zipnames = zf.namelist()
+            self.assertEqual(list(sorted(ponies)), list(sorted(zipnames)))
+            for name in zipnames:
+                contents = zf.open(name, "r").read()
+                self.assertEqual(("%s ponies\n" % name).encode("ascii"),
+                                 contents)
+
+    def test_unknown(self):
+        filename = "unknown"
+        send_dir = self.mktemp()
+        os.mkdir(send_dir)
+        abs_filename = os.path.abspath(os.path.join(send_dir, filename))
+
+        try:
+            os.mkfifo(abs_filename)
+        except OSError:
+            raise unittest.SkipTest("is mkfifo supported on this platform?")
+        self.assertFalse(os.path.isfile(abs_filename))
+        self.assertFalse(os.path.isdir(abs_filename))
+
+        send_args = [ "send", filename ]
+        args = runner.parser.parse_args(send_args)
+        args.cwd = send_dir
+        args.stdout = io.StringIO()
+        args.stderr = io.StringIO()
+
+        e = self.assertRaises(TypeError, build_phase1_data, args)
+        self.assertEqual(str(e),
+                         "'%s' is neither file nor directory" % filename)
+
 
 class ScriptsBase:
     def find_executable(self):