Add noms.copy.Peers()

As I was working on making deployment files get staged by Go/Python,
another pattern emerged. It seems like it will be not-uncommon to want
to stage all the files in the directory your script is in over to the
staging directory the system made for you. So, provide a helper to do
that.

tools/noms/copy.py

@@ -0,0 +1,28 @@
+#!/usr/bin/python
+
+import os.path, shutil
+
+def Peers(me, dstDir):
+	"""Peers copies the peers of me into dstDir.
+
+	Peers looks for files, directories and symlinks next to me
+	and copies them (with the same basenames) to dstDir, which is
+	presumed to exist.
+	"""
+	myDir = os.path.dirname(os.path.abspath(me))
+	names = os.listdir(myDir)
+	for basename in names:
+		src = os.path.join(myDir, basename)
+		dst = os.path.join(dstDir, basename)
+		if os.path.samefile(me, src):
+			continue
+
+		if os.path.islink(src):
+			linkto = os.readlink(src)
+			os.symlink(linkto, dst)
+		elif os.path.isfile(src):
+			shutil.copy2(src, dst)
+		elif os.path.isdir(src):
+			shutil.copytree(src, dst)
+		else:
+			raise Exception("Unknown file type at " + src)

tools/noms/copy_test.py

@@ -0,0 +1,38 @@
+#!/usr/bin/python
+
+import os, os.path, shutil, tempfile, unittest
+import copy
+
+class TestCopy(unittest.TestCase):
+	def setUp(self):
+		self.tempdir = os.path.realpath(tempfile.mkdtemp())
+
+
+	def tearDown(self):
+		shutil.rmtree(self.tempdir, ignore_errors=True)
+
+
+	def test_CopyPeers(self):
+		nested = tempfile.mkdtemp(dir=self.tempdir)
+		otherNested = tempfile.mkdtemp(dir=self.tempdir)
+
+		def mkfile():
+			ret = tempfile.NamedTemporaryFile(dir=nested, delete=False)
+			ret.close()
+			return ret.name
+
+		me = mkfile()
+		peerFile = os.path.basename(mkfile())
+		peerDir = os.path.basename(tempfile.mkdtemp(dir=nested))
+		peerLink = 'link'
+		peerLinkAbs = os.path.join(nested, 'link')
+		os.symlink(peerFile, peerLinkAbs)
+
+		copy.Peers(me, otherNested)
+		self.assertTrue(os.path.islink(os.path.join(otherNested, peerLink)))
+		self.assertTrue(os.path.isfile(os.path.join(otherNested, peerFile)))
+		self.assertTrue(os.path.isdir(os.path.join(otherNested, peerDir)))
+
+
+if __name__ == '__main__':
+    unittest.main()

tools/noms/staging_test.py

@@ -4,8 +4,6 @@ import os, os.path, shutil, tempfile, unittest
 import staging
 
 class TestStaging(unittest.TestCase):
-	CONTENTS = 'test file contents'
-
 	def setUp(self):
 		self.tempdir = os.path.realpath(tempfile.mkdtemp())
 		self.nested = tempfile.mkdtemp(dir=self.tempdir)