From: Brian Warner <warner@allmydata.com>
Date: Wed, 5 Dec 2007 06:01:37 +0000 (-0700)
Subject: refactor web tests, and interfaces.IFileNode
X-Git-Url: https://git.rkrishnan.org/components/com_hotproperty/%22doc.html/...?a=commitdiff_plain;h=f190382d5e57fc4542063c853333e856780ff057;p=tahoe-lafs%2Ftahoe-lafs.git

refactor web tests, and interfaces.IFileNode
---

diff --git a/src/allmydata/interfaces.py b/src/allmydata/interfaces.py
index bea99976..42699d42 100644
--- a/src/allmydata/interfaces.py
+++ b/src/allmydata/interfaces.py
@@ -382,27 +382,6 @@ class IReadonlyNewDirectoryURI(Interface):
 
 
 class IFilesystemNode(Interface):
-    def get_uri():
-        """Return the URI that can be used by others to get access to this
-        file or directory.
-        """
-
-    def get_verifier():
-        """Return an IVerifierURI instance that represents the
-        'verifiy/refresh capability' for this node. The holder of this
-        capability will be able to renew the lease for this node, protecting
-        it from garbage-collection. They will also be able to ask a server if
-        it holds a share for the file or directory.
-        """
-
-    def check():
-        """Perform a file check. See IChecker.check for details."""
-
-    def is_mutable():
-        """Return True if this file or directory is mutable, False if it is read-only.
-        """
-
-class IMutableFilesystemNode(IFilesystemNode):
     def get_uri():
         """
         Return the URI that can be used by others to get access to this
@@ -423,6 +402,35 @@ class IMutableFilesystemNode(IFilesystemNode):
         get_readonly_uri() will return the same thing as get_uri().
         """
 
+    def get_verifier():
+        """Return an IVerifierURI instance that represents the
+        'verifiy/refresh capability' for this node. The holder of this
+        capability will be able to renew the lease for this node, protecting
+        it from garbage-collection. They will also be able to ask a server if
+        it holds a share for the file or directory.
+        """
+
+    def check():
+        """Perform a file check. See IChecker.check for details."""
+
+    def is_readonly():
+        """Return True if this reference provides mutable access to the given
+        file or directory (i.e. if you can modify it), or False if not. Note
+        that even if this reference is read-only, someone else may hold a
+        read-write reference to it."""
+
+    def is_mutable():
+        """Return True if this file or directory is mutable (by *somebody*,
+        not necessarily you), False if it is is immutable. Note that a file
+        might be mutable overall, but your reference to it might be
+        read-only. On the other hand, all references to an immutable file
+        will be read-only; there are no read-write references to an immutable
+        file.
+        """
+
+class IMutableFilesystemNode(IFilesystemNode):
+    pass
+
 class IFileNode(IFilesystemNode):
     def download(target):
         """Download the file's contents to a given IDownloadTarget"""
@@ -488,7 +496,9 @@ class IDirectoryNode(IMutableFilesystemNode):
 
     def list():
         """I return a Deferred that fires with a dictionary mapping child
-        name to an IFileNode or IDirectoryNode."""
+        name to (node, metadata_dict) tuples, in which 'node' is either an
+        IFileNode or IDirectoryNode, and 'metadata_dict' is a dictionary of
+        metadata."""
 
     def has_child(name):
         """I return a Deferred that fires with a boolean, True if there
diff --git a/src/allmydata/test/common.py b/src/allmydata/test/common.py
new file mode 100644
index 00000000..5addc567
--- /dev/null
+++ b/src/allmydata/test/common.py
@@ -0,0 +1,113 @@
+
+import os
+from zope.interface import implements
+from twisted.internet import defer
+from twisted.python import failure
+from allmydata import uri, dirnode
+from allmydata.interfaces import IURI, IMutableFileNode, IFileNode
+from allmydata.encode import NotEnoughPeersError
+
+class FakeCHKFileNode:
+    """I provide IFileNode, but all of my data is stored in a class-level
+    dictionary."""
+    implements(IFileNode)
+    all_contents = {}
+
+    def __init__(self, u, client):
+        self.client = client
+        self.my_uri = u.to_string()
+
+    def get_uri(self):
+        return self.my_uri
+    def get_readonly_uri(self):
+        return self.my_uri
+    def get_verifier(self):
+        return IURI(self.my_uri).get_verifier()
+    def check(self):
+        return defer.succeed(None)
+    def is_mutable(self):
+        return False
+    def is_readonly(self):
+        return True
+
+    def download(self, target):
+        if self.my_uri not in self.all_contents:
+            f = failure.Failure(NotEnoughPeersError())
+            target.fail(f)
+            return defer.fail(f)
+        data = self.all_contents[self.my_uri]
+        target.open(len(data))
+        target.write(data)
+        target.close()
+        return defer.maybeDeferred(target.finish)
+    def download_to_data(self):
+        if self.my_uri not in self.all_contents:
+            return defer.fail(NotEnoughPeersError())
+        data = self.all_contents[self.my_uri]
+        return defer.succeed(data)
+    def get_size(self):
+        data = self.all_contents[self.my_uri]
+        return len(data)
+
+def make_chk_file_uri(size):
+    return uri.CHKFileURI(key=os.urandom(16),
+                          uri_extension_hash=os.urandom(32),
+                          needed_shares=3,
+                          total_shares=10,
+                          size=size)
+
+def create_chk_filenode(client, contents):
+    u = make_chk_file_uri(len(contents))
+    n = FakeCHKFileNode(u, client)
+    FakeCHKFileNode.all_contents[u.to_string()] = contents
+    return n
+
+
+class FakeMutableFileNode:
+    """I provide IMutableFileNode, but all of my data is stored in a
+    class-level dictionary."""
+
+    implements(IMutableFileNode)
+    all_contents = {}
+    def __init__(self, client):
+        self.client = client
+        self.my_uri = make_mutable_file_uri()
+        self.storage_index = self.my_uri.storage_index
+    def create(self, initial_contents, wait_for_numpeers=None):
+        self.all_contents[self.storage_index] = initial_contents
+        return defer.succeed(self)
+    def init_from_uri(self, myuri):
+        self.my_uri = IURI(myuri)
+        self.storage_index = self.my_uri.storage_index
+        return self
+    def get_uri(self):
+        return self.my_uri
+    def is_readonly(self):
+        return self.my_uri.is_readonly()
+    def is_mutable(self):
+        return self.my_uri.is_mutable()
+    def download_to_data(self):
+        return defer.succeed(self.all_contents[self.storage_index])
+    def get_writekey(self):
+        return "\x00"*16
+
+    def replace(self, new_contents, wait_for_numpeers=None):
+        assert not self.is_readonly()
+        self.all_contents[self.storage_index] = new_contents
+        return defer.succeed(None)
+
+
+def make_mutable_file_uri():
+    return uri.WriteableSSKFileURI(writekey=os.urandom(16),
+                                   fingerprint=os.urandom(32))
+def make_verifier_uri():
+    return uri.SSKVerifierURI(storage_index=os.urandom(16),
+                              fingerprint=os.urandom(32))
+
+class NonGridDirectoryNode(dirnode.NewDirectoryNode):
+    """This offers IDirectoryNode, but uses a FakeMutableFileNode for the
+    backing store, so it doesn't go to the grid. The child data is still
+    encrypted and serialized, so this isn't useful for tests that want to
+    look inside the dirnodes and check their contents.
+    """
+    filenode_class = FakeMutableFileNode
diff --git a/src/allmydata/test/test_dirnode.py b/src/allmydata/test/test_dirnode.py
index 328f692b..07bef1a0 100644
--- a/src/allmydata/test/test_dirnode.py
+++ b/src/allmydata/test/test_dirnode.py
@@ -1,62 +1,18 @@
 
-import os
 from zope.interface import implements
 from twisted.trial import unittest
-from twisted.internet import defer
 from allmydata import uri, dirnode, upload
 from allmydata.interfaces import IURI, IClient, IMutableFileNode, \
      INewDirectoryURI, IReadonlyNewDirectoryURI, IFileNode
 from allmydata.util import hashutil, testutil
+from allmydata.test.common import make_chk_file_uri, make_mutable_file_uri, \
+     NonGridDirectoryNode, create_chk_filenode
 
 # to test dirnode.py, we want to construct a tree of real DirectoryNodes that
 # contain pointers to fake files. We start with a fake MutableFileNode that
 # stores all of its data in a static table.
 
-def make_chk_file_uri(size):
-    return uri.CHKFileURI(key=os.urandom(16),
-                          uri_extension_hash=os.urandom(32),
-                          needed_shares=3,
-                          total_shares=10,
-                          size=size)
-
-def make_mutable_file_uri():
-    return uri.WriteableSSKFileURI(writekey=os.urandom(16),
-                                   fingerprint=os.urandom(32))
-def make_verifier_uri():
-    return uri.SSKVerifierURI(storage_index=os.urandom(16),
-                              fingerprint=os.urandom(32))
-
-class FakeMutableFileNode:
-    implements(IMutableFileNode)
-    all_contents = {}
-    def __init__(self, client):
-        self.client = client
-        self.my_uri = make_mutable_file_uri()
-        self.storage_index = self.my_uri.storage_index
-    def create(self, initial_contents, wait_for_numpeers=None):
-        self.all_contents[self.storage_index] = initial_contents
-        return defer.succeed(self)
-    def init_from_uri(self, myuri):
-        self.my_uri = IURI(myuri)
-        self.storage_index = self.my_uri.storage_index
-        return self
-    def get_uri(self):
-        return self.my_uri
-    def is_readonly(self):
-        return self.my_uri.is_readonly()
-    def is_mutable(self):
-        return self.my_uri.is_mutable()
-    def download_to_data(self):
-        return defer.succeed(self.all_contents[self.storage_index])
-    def get_writekey(self):
-        return "\x00"*16
-
-    def replace(self, new_contents, wait_for_numpeers=None):
-        self.all_contents[self.storage_index] = new_contents
-        return defer.succeed(None)
-
-class MyDirectoryNode(dirnode.NewDirectoryNode):
-    filenode_class = FakeMutableFileNode
+MyDirectoryNode = NonGridDirectoryNode
 
 class Marker:
     implements(IFileNode, IMutableFileNode) # sure, why not
@@ -81,16 +37,14 @@ class Marker:
 
 class FakeClient:
     implements(IClient)
-    chk_contents = {}
 
     def upload(self, uploadable, wait_for_numpeers):
         d = uploadable.get_size()
         d.addCallback(lambda size: uploadable.read(size))
         def _got_data(datav):
             data = "".join(datav)
-            u = make_chk_file_uri(len(data))
-            self.chk_contents[u] = data
-            return u
+            n = create_chk_filenode(self, data)
+            return n.get_uri()
         d.addCallback(_got_data)
         return d
 
diff --git a/src/allmydata/test/test_mutable.py b/src/allmydata/test/test_mutable.py
index 4f66afa0..a1b7bc9c 100644
--- a/src/allmydata/test/test_mutable.py
+++ b/src/allmydata/test/test_mutable.py
@@ -11,6 +11,9 @@ from allmydata.interfaces import IURI, INewDirectoryURI, \
 from allmydata.filenode import LiteralFileNode
 import sha
 
+#from allmydata.test.common import FakeMutableFileNode
+#FakeFilenode = FakeMutableFileNode
+
 class FakeFilenode(mutable.MutableFileNode):
     counter = itertools.count(1)
     all_contents = {}
diff --git a/src/allmydata/test/test_web.py b/src/allmydata/test/test_web.py
index 40e4a6b5..831d596d 100644
--- a/src/allmydata/test/test_web.py
+++ b/src/allmydata/test/test_web.py
@@ -1,17 +1,14 @@
 
 import re, os.path, urllib
-from zope.interface import implements
 from twisted.application import service
 from twisted.trial import unittest
 from twisted.internet import defer
 from twisted.web import client, error, http
 from twisted.python import failure, log
-from allmydata import dirnode, webish, interfaces, uri, provisioning, filenode
-from allmydata.encode import NotEnoughPeersError
+from allmydata import webish, interfaces, provisioning
 from allmydata.util import fileutil
-import itertools
-
-import test_mutable
+from allmydata.test.common import NonGridDirectoryNode, FakeCHKFileNode, FakeMutableFileNode, create_chk_filenode
+from allmydata.interfaces import IURI, INewDirectoryURI, IReadonlyNewDirectoryURI, IFileURI, IMutableFileURI
 
 # create a fake uploader/downloader, and a couple of fake dirnodes, then
 # create a webserver that works against them
@@ -32,73 +29,36 @@ class MyClient(service.MultiService):
         return []
 
     def create_node_from_uri(self, uri):
-        return self.my_nodes[uri]
+        u = IURI(uri)
+        if (INewDirectoryURI.providedBy(u)
+            or IReadonlyNewDirectoryURI.providedBy(u)):
+            return NonGridDirectoryNode(self).init_from_uri(u)
+        if IFileURI.providedBy(u):
+            return FakeCHKFileNode(u, self)
+        assert IMutableFileURI.providedBy(u), u
+        return FakeMutableFileNode(self).init_from_uri(u)
 
     def create_empty_dirnode(self, wait_for_numpeers=None):
-        n = FakeDirectoryNode(self)
-        r = defer.succeed(n.fake_create(wait_for_numpeers=1))
-        self.my_nodes[n.get_uri()] = n
-        nro = FakeDirectoryNode(self)
-        nro.init_from_uri(n.get_readonly_uri())
-        nro._node.all_rw_friends[nro._node.get_uri()] = n._node.get_uri()
-        self.my_nodes[nro.get_uri()] = nro
-        return r
+        n = NonGridDirectoryNode(self)
+        d = n.create(wait_for_numpeers)
+        d.addCallback(lambda res: n)
+        return d
 
-    def upload(self, uploadable, wait_for_numpeers=None):
-        uploader = self.getServiceNamed("uploader")
-        return uploader.upload(uploadable, wait_for_numpeers=wait_for_numpeers)
-
-
-class MyDownloader(service.Service):
-    implements(interfaces.IDownloader)
-    name = "downloader"
-    def __init__(self, files):
-        self.files = files
-
-    def download(self, uri, target):
-        if uri not in self.files:
-            e = NotEnoughPeersError()
-            f = failure.Failure(e)
-            target.fail(f)
-            return defer.fail(f)
-        data = self.files[uri]
-        target.open(len(data))
-        target.write(data)
-        target.close()
-        return defer.maybeDeferred(target.finish)
-
-uri_counter = itertools.count()
-
-def make_newuri(data):
-    n = uri_counter.next()
-    assert len(str(n)) < 5
-    newuri = uri.CHKFileURI(key="K%05d" % n + "k"*10,
-                            uri_extension_hash="EH" + "h"*30,
-                            needed_shares=25,
-                            total_shares=100,
-                            size=len(data))
-    return newuri.to_string()
-
-class MyUploader(service.Service):
-    implements(interfaces.IUploader)
-    name = "uploader"
-    def __init__(self, files, nodes):
-        self.files = files
-        self.nodes = nodes
+    def create_mutable_file(self, contents="", wait_for_numpeers=None):
+        n = FakeMutableFileNode(self)
+        return n.create(contents)
 
     def upload(self, uploadable, wait_for_numpeers=None):
         d = uploadable.get_size()
         d.addCallback(lambda size: uploadable.read(size))
-        d.addCallback(lambda data: "".join(data))
-        def _got_data(data):
-            newuri = make_newuri(data)
-            self.files[newuri] = data
-            self.nodes[newuri] = MyFileNode(newuri, self.parent)
-            uploadable.close()
-            return newuri
+        def _got_data(datav):
+            data = "".join(datav)
+            n = create_chk_filenode(self, data)
+            return n.get_uri()
         d.addCallback(_got_data)
         return d
 
+
 def syncwrap(meth):
     """
     syncwrap invokes a method, assumes that it fired its deferred
@@ -112,8 +72,8 @@ def syncwrap(meth):
         return l[0]
     return _syncwrapped_meth
 
-class FakeDirectoryNode(dirnode.NewDirectoryNode):
-    filenode_class = test_mutable.FakeFilenode
+class FakeDirectoryNode: #(dirnode.NewDirectoryNode):
+    #filenode_class = test_mutable.FakeFilenode
 
     @syncwrap
     def fake_create(self, wait_for_numpeers=None):
@@ -135,9 +95,6 @@ class FakeDirectoryNode(dirnode.NewDirectoryNode):
     def fake_set_uri(self, name, uri):
         return self.set_uri(name, uri)
 
-class MyFileNode(filenode.FileNode):
-    pass
-
 class WebMixin(object):
     def setUp(self):
         self.s = MyClient()
@@ -148,15 +105,6 @@ class WebMixin(object):
         port = s.listener._port.getHost().port
         self.webish_url = "http://localhost:%d" % port
 
-        self.nodes = {} # maps URI to node
-        self.s.my_nodes = self.nodes
-        self.files = {} # maps file URI to contents
-
-        dl = MyDownloader(self.files)
-        dl.setServiceParent(self.s)
-        ul = MyUploader(self.files, self.nodes)
-        ul.setServiceParent(self.s)
-
         l = [ self.s.create_empty_dirnode() for x in range(6) ]
         d = defer.DeferredList(l)
         def _then(res):
@@ -169,23 +117,26 @@ class WebMixin(object):
             self._foo_node = foo
             self._foo_uri = foo.get_uri()
             self._foo_readonly_uri = foo.get_readonly_uri()
-            self.public_root.set_uri("foo", foo.get_uri()) # ignore the deferred because we know the fake one does this synchronously
+            # NOTE: we ignore the deferred on all set_uri() calls, because we
+            # know the fake nodes do these synchronously
+            self.public_root.set_uri("foo", foo.get_uri())
 
-            self._bar_txt_uri = self.makefile(0)
-            self.BAR_CONTENTS = self.files[self._bar_txt_uri]
+            self.BAR_CONTENTS, n, self._bar_txt_uri = self.makefile(0)
             foo.set_uri("bar.txt", self._bar_txt_uri)
             foo.set_uri("empty", res[3][1].get_uri())
             sub_uri = res[4][1].get_uri()
-            sub = foo.fake_set_uri("sub", sub_uri)
+            foo.set_uri("sub", sub_uri)
+            sub = self.s.create_node_from_uri(sub_uri)
 
-            blocking_uri = self.make_smallfile(1)
+            _ign, n, blocking_uri = self.makefile(1)
             foo.set_uri("blockingfile", blocking_uri)
 
-            baz_file = self.makefile(2)
+            _ign, n, baz_file = self.makefile(2)
             sub.set_uri("baz.txt", baz_file)
 
-            self._bad_file_uri = self.makefile(3)
-            del self.files[self._bad_file_uri]
+            _ign, n, self._bad_file_uri = self.makefile(3)
+            # this uri should not be downloadable
+            del FakeCHKFileNode.all_contents[self._bad_file_uri]
 
             rodir = res[5][1]
             self.public_root.set_uri("reedownlee", rodir.get_readonly_uri())
@@ -205,31 +156,9 @@ class WebMixin(object):
         return d
 
     def makefile(self, number):
-        n = str(number)
-
-        assert len(n) == 1
-        newuri = uri.CHKFileURI(key="K" + n*15,
-                                uri_extension_hash="EH" + n*30,
-                                needed_shares=25,
-                                total_shares=100,
-                                size=123+number).to_string()
-        assert newuri not in self.files
-        node = MyFileNode(newuri, self.s)
-        contents = "contents of file %s\n" % n
-        self.files[newuri] = contents
-        self.nodes[newuri] = node
-        return newuri
-
-    def make_smallfile(self, number):
-        n = str(number)
-        assert len(n) == 1
-        contents = "small data %s\n" % n
-        newuri = uri.LiteralFileURI(contents).to_string()
-        assert newuri not in self.files
-        node = MyFileNode(newuri, self.s)
-        self.files[newuri] = contents
-        self.nodes[newuri] = node
-        return newuri
+        contents = "contents of file %s\n" % number
+        n = create_chk_filenode(self.s, contents)
+        return contents, n, n.get_uri()
 
     def tearDown(self):
         return self.s.stopService()
@@ -251,7 +180,7 @@ class WebMixin(object):
         self.failUnless(isinstance(data[1], dict))
         self.failIf("rw_uri" in data[1]) # immutable
         self.failUnlessEqual(data[1]["ro_uri"], self._bar_txt_uri)
-        self.failUnlessEqual(data[1]["size"], 123)
+        self.failUnlessEqual(data[1]["size"], len(self.BAR_CONTENTS))
 
     def failUnlessIsFooJSON(self, res):
         data = self.worlds_cheapest_json_decoder(res)
@@ -268,7 +197,7 @@ class WebMixin(object):
         kids = data[1]["children"]
         self.failUnlessEqual(kids["sub"][0], "dirnode")
         self.failUnlessEqual(kids["bar.txt"][0], "filenode")
-        self.failUnlessEqual(kids["bar.txt"][1]["size"], 123)
+        self.failUnlessEqual(kids["bar.txt"][1]["size"], len(self.BAR_CONTENTS))
         self.failUnlessEqual(kids["bar.txt"][1]["ro_uri"], self._bar_txt_uri)
 
     def GET(self, urlpath, followRedirect=False):
@@ -469,28 +398,22 @@ class Web(WebMixin, unittest.TestCase):
 
     def test_PUT_NEWFILEURL(self):
         d = self.PUT(self.public_url + "/foo/new.txt", self.NEWFILE_CONTENTS)
-        def _check(res):
-            # TODO: we lose the response code, so we can't check this
-            #self.failUnlessEqual(responsecode, 201)
-            self.failUnless(self._foo_node.fake_has_child("new.txt"))
-            new_uri = self._foo_node.fake_get("new.txt").get_uri()
-            new_contents = self.files[new_uri]
-            self.failUnlessEqual(new_contents, self.NEWFILE_CONTENTS)
-            self.failUnlessEqual(res.strip(), new_uri)
-        d.addCallback(_check)
+        # TODO: we lose the response code, so we can't check this
+        #self.failUnlessEqual(responsecode, 201)
+        d.addCallback(self.failUnlessURIMatchesChild, self._foo_node, "new.txt")
+        d.addCallback(lambda res:
+                      self.failUnlessChildContentsAre(self._foo_node, "new.txt",
+                                                      self.NEWFILE_CONTENTS))
         return d
 
     def test_PUT_NEWFILEURL_replace(self):
         d = self.PUT(self.public_url + "/foo/bar.txt", self.NEWFILE_CONTENTS)
-        def _check(res):
-            # TODO: we lose the response code, so we can't check this
-            #self.failUnlessEqual(responsecode, 200)
-            self.failUnless(self._foo_node.fake_has_child("bar.txt"))
-            new_node = self._foo_node.fake_get("bar.txt")
-            new_contents = self.files[new_node.get_uri()]
-            self.failUnlessEqual(new_contents, self.NEWFILE_CONTENTS)
-            self.failUnlessEqual(res.strip(), new_node.get_uri())
-        d.addCallback(_check)
+        # TODO: we lose the response code, so we can't check this
+        #self.failUnlessEqual(responsecode, 200)
+        d.addCallback(self.failUnlessURIMatchesChild, self._foo_node, "bar.txt")
+        d.addCallback(lambda res:
+                      self.failUnlessChildContentsAre(self._foo_node, "bar.txt",
+                                                      self.NEWFILE_CONTENTS))
         return d
 
     def test_PUT_NEWFILEURL_no_replace(self):
@@ -504,16 +427,13 @@ class Web(WebMixin, unittest.TestCase):
 
     def test_PUT_NEWFILEURL_mkdirs(self):
         d = self.PUT(self.public_url + "/foo/newdir/new.txt", self.NEWFILE_CONTENTS)
-        def _check(res):
-            self.failIf(self._foo_node.fake_has_child("new.txt"))
-            self.failUnless(self._foo_node.fake_has_child("newdir"))
-            newdir_node = self._foo_node.fake_get("newdir")
-            self.failUnless(newdir_node.fake_has_child("new.txt"))
-            new_node = newdir_node.fake_get("new.txt")
-            new_contents = self.files[new_node.get_uri()]
-            self.failUnlessEqual(new_contents, self.NEWFILE_CONTENTS)
-            self.failUnlessEqual(res.strip(), new_node.get_uri())
-        d.addCallback(_check)
+        fn = self._foo_node
+        d.addCallback(self.failUnlessURIMatchesChild, fn, "newdir/new.txt")
+        d.addCallback(lambda res: self.failIfNodeHasChild(fn, "new.txt"))
+        d.addCallback(lambda res: self.failUnlessNodeHasChild(fn, "newdir"))
+        d.addCallback(lambda res:
+                      self.failUnlessChildContentsAre(fn, "newdir/new.txt",
+                                                      self.NEWFILE_CONTENTS))
         return d
 
     def test_PUT_NEWFILEURL_blocked(self):
@@ -526,9 +446,8 @@ class Web(WebMixin, unittest.TestCase):
 
     def test_DELETE_FILEURL(self):
         d = self.DELETE(self.public_url + "/foo/bar.txt")
-        def _check(res):
-            self.failIf(self._foo_node.fake_has_child("bar.txt"))
-        d.addCallback(_check)
+        d.addCallback(lambda res:
+                      self.failIfNodeHasChild(self._foo_node, "bar.txt"))
         return d
 
     def test_DELETE_FILEURL_missing(self):
@@ -625,13 +544,10 @@ class Web(WebMixin, unittest.TestCase):
         f.write(self.NEWFILE_CONTENTS)
         f.close()
         d = self.PUT(url, "")
-        def _check(res):
-            self.failUnless(self._foo_node.fake_has_child("new.txt"))
-            new_node = self._foo_node.fake_get("new.txt")
-            new_contents = self.files[new_node.get_uri()]
-            self.failUnlessEqual(new_contents, self.NEWFILE_CONTENTS)
-            self.failUnlessEqual(res.strip(), new_node.get_uri())
-        d.addCallback(_check)
+        d.addCallback(self.failUnlessURIMatchesChild, self._foo_node, "new.txt")
+        d.addCallback(lambda res:
+                      self.failUnlessChildContentsAre(self._foo_node, "new.txt",
+                                                      self.NEWFILE_CONTENTS))
         return d
 
     def test_PUT_NEWFILEURL_localfile_disabled(self):
@@ -656,16 +572,16 @@ class Web(WebMixin, unittest.TestCase):
         f.close()
         d = self.PUT(self.public_url + "/foo/newdir/new.txt?t=upload&localfile=%s"
                      % localfile, "")
-        def _check(res):
-            self.failIf(self._foo_node.fake_has_child("new.txt"))
-            self.failUnless(self._foo_node.fake_has_child("newdir"))
-            newdir_node = self._foo_node.fake_get("newdir")
-            self.failUnless(newdir_node.fake_has_child("new.txt"))
-            new_node = newdir_node.fake_get("new.txt")
-            new_contents = self.files[new_node.get_uri()]
-            self.failUnlessEqual(new_contents, self.NEWFILE_CONTENTS)
-            self.failUnlessEqual(res.strip(), new_node.get_uri())
-        d.addCallback(_check)
+        d.addCallback(self.failUnlessURIMatchesChild,
+                      self._foo_node, "newdir/new.txt")
+        d.addCallback(lambda res:
+                      self.failIfNodeHasChild(self._foo_node, "new.txt"))
+        d.addCallback(lambda res:
+                      self.failUnlessNodeHasChild(self._foo_node, "newdir"))
+        d.addCallback(lambda res:
+                      self.failUnlessChildContentsAre(self._foo_node,
+                                                      "newdir/new.txt",
+                                                      self.NEWFILE_CONTENTS))
         return d
 
     def test_GET_FILEURL_uri(self):
@@ -695,7 +611,7 @@ class Web(WebMixin, unittest.TestCase):
                                       '<a href="[^"]+bar.txt">bar.txt</a>'
                                       '</td>'
                                       '\s+<td>FILE</td>'
-                                      '\s+<td>123</td>'
+                                      '\s+<td>%d</td>' % len(self.BAR_CONTENTS)
                                       , res))
             self.failUnless(re.search(r'<td><a href="sub">sub</a></td>'
                                       '\s+<td>DIR</td>', res))
@@ -747,20 +663,18 @@ class Web(WebMixin, unittest.TestCase):
 
     def test_PUT_NEWDIRURL(self):
         d = self.PUT(self.public_url + "/foo/newdir?t=mkdir", "")
-        def _check(res):
-            self.failUnless(self._foo_node.fake_has_child("newdir"))
-            newdir_node = self._foo_node.fake_get("newdir")
-            self.failIf(newdir_node.fake_list())
-        d.addCallback(_check)
+        d.addCallback(lambda res:
+                      self.failUnlessNodeHasChild(self._foo_node, "newdir"))
+        d.addCallback(lambda res: self._foo_node.get("newdir"))
+        d.addCallback(self.failUnlessNodeKeysAre, [])
         return d
 
     def test_PUT_NEWDIRURL_replace(self):
         d = self.PUT(self.public_url + "/foo/sub?t=mkdir", "")
-        def _check(res):
-            self.failUnless(self._foo_node.fake_has_child("sub"))
-            newdir_node = self._foo_node.fake_get("sub")
-            self.failIf(newdir_node.fake_list())
-        d.addCallback(_check)
+        d.addCallback(lambda res:
+                      self.failUnlessNodeHasChild(self._foo_node, "sub"))
+        d.addCallback(lambda res: self._foo_node.get("sub"))
+        d.addCallback(self.failUnlessNodeKeysAre, [])
         return d
 
     def test_PUT_NEWDIRURL_no_replace(self):
@@ -769,38 +683,34 @@ class Web(WebMixin, unittest.TestCase):
                   "409 Conflict",
                   "There was already a child by that name, and you asked me "
                   "to not replace it")
-        def _check(res):
-            self.failUnless(self._foo_node.fake_has_child("sub"))
-            newdir_node = self._foo_node.fake_get("sub")
-            self.failUnlessEqual(newdir_node.fake_list().keys(), ["baz.txt"])
-        d.addCallback(_check)
+        d.addCallback(lambda res:
+                      self.failUnlessNodeHasChild(self._foo_node, "sub"))
+        d.addCallback(lambda res: self._foo_node.get("sub"))
+        d.addCallback(self.failUnlessNodeKeysAre, ["baz.txt"])
         return d
 
     def test_PUT_NEWDIRURL_mkdirs(self):
         d = self.PUT(self.public_url + "/foo/subdir/newdir?t=mkdir", "")
-        def _check(res):
-            self.failIf(self._foo_node.fake_has_child("newdir"))
-            self.failUnless(self._foo_node.fake_has_child("subdir"))
-            subdir_node = self._foo_node.fake_get("subdir")
-            self.failUnless(subdir_node.fake_has_child("newdir"))
-            newdir_node = subdir_node.fake_get("newdir")
-            self.failIf(newdir_node.fake_list())
-        d.addCallback(_check)
+        d.addCallback(lambda res:
+                      self.failIfNodeHasChild(self._foo_node, "newdir"))
+        d.addCallback(lambda res:
+                      self.failUnlessNodeHasChild(self._foo_node, "subdir"))
+        d.addCallback(lambda res:
+                      self._foo_node.get_child_at_path("subdir/newdir"))
+        d.addCallback(self.failUnlessNodeKeysAre, [])
         return d
 
     def test_DELETE_DIRURL(self):
         d = self.DELETE(self.public_url + "/foo")
-        def _check(res):
-            self.failIf(self.public_root.fake_has_child("foo"))
-        d.addCallback(_check)
+        d.addCallback(lambda res:
+                      self.failIfNodeHasChild(self.public_root, "foo"))
         return d
 
     def test_DELETE_DIRURL_missing(self):
         d = self.DELETE(self.public_url + "/foo/missing")
         d.addBoth(self.should404, "test_DELETE_DIRURL_missing")
-        def _check(res):
-            self.failUnless(self.public_root.fake_has_child("foo"))
-        d.addCallback(_check)
+        d.addCallback(lambda res:
+                      self.failUnlessNodeHasChild(self.public_root, "foo"))
         return d
 
     def test_DELETE_DIRURL_missing2(self):
@@ -896,6 +806,47 @@ class Web(WebMixin, unittest.TestCase):
         for path,node in self.walk_mynodes(self.public_root):
             print path
 
+    def failUnlessNodeKeysAre(self, node, expected_keys):
+        d = node.list()
+        def _check(children):
+            self.failUnlessEqual(sorted(children.keys()), sorted(expected_keys))
+        d.addCallback(_check)
+        return d
+    def failUnlessNodeHasChild(self, node, name):
+        d = node.list()
+        def _check(children):
+            self.failUnless(name in children)
+        d.addCallback(_check)
+        return d
+    def failIfNodeHasChild(self, node, name):
+        d = node.list()
+        def _check(children):
+            self.failIf(name in children)
+        d.addCallback(_check)
+        return d
+
+    def failUnlessChildContentsAre(self, node, name, expected_contents):
+        d = node.get_child_at_path(name)
+        d.addCallback(lambda node: node.download_to_data())
+        def _check(contents):
+            self.failUnlessEqual(contents, expected_contents)
+        d.addCallback(_check)
+        return d
+
+    def failUnlessChildURIIs(self, node, name, expected_uri):
+        d = node.get_child_at_path(name)
+        def _check(child):
+            self.failUnlessEqual(child.get_uri(), expected_uri.strip())
+        d.addCallback(_check)
+        return d
+
+    def failUnlessURIMatchesChild(self, got_uri, node, name):
+        d = node.get_child_at_path(name)
+        def _check(child):
+            self.failUnlessEqual(got_uri.strip(), child.get_uri())
+        d.addCallback(_check)
+        return d
+
     def test_PUT_NEWDIRURL_localdir(self):
         localdir = os.path.abspath("web/PUT_NEWDIRURL_localdir")
         # create some files there
@@ -909,21 +860,20 @@ class Web(WebMixin, unittest.TestCase):
 
         d = self.PUT(self.public_url + "/newdir?t=upload&localdir=%s"
                      % localdir, "")
-        def _check(res):
-            self.failUnless(self.public_root.fake_has_child("newdir"))
-            newnode = self.public_root.fake_get("newdir")
-            self.failUnlessEqual(sorted(newnode.fake_list().keys()),
-                                 sorted(["one", "two", "three", "zap.zip"]))
-            onenode = newnode.fake_get("one")
-            self.failUnlessEqual(sorted(onenode.fake_list().keys()),
-                                 sorted(["sub"]))
-            threenode = newnode.fake_get("three")
-            self.failUnlessEqual(sorted(threenode.fake_list().keys()),
-                                 sorted(["foo.txt", "bar.txt"]))
-            barnode = threenode.fake_get("bar.txt")
-            contents = self.files[barnode.get_uri()]
-            self.failUnlessEqual(contents, "contents of three/bar.txt\n")
-        d.addCallback(_check)
+        pr = self.public_root
+        d.addCallback(lambda res: self.failUnlessNodeHasChild(pr, "newdir"))
+        d.addCallback(lambda res: pr.get("newdir"))
+        d.addCallback(self.failUnlessNodeKeysAre,
+                      ["one", "two", "three", "zap.zip"])
+        d.addCallback(lambda res: pr.get_child_at_path("newdir/one"))
+        d.addCallback(self.failUnlessNodeKeysAre, ["sub"])
+        d.addCallback(lambda res: pr.get_child_at_path("newdir/three"))
+        d.addCallback(self.failUnlessNodeKeysAre, ["foo.txt", "bar.txt"])
+        d.addCallback(lambda res: pr.get_child_at_path("newdir/three/bar.txt"))
+        d.addCallback(lambda barnode: barnode.download_to_data())
+        d.addCallback(lambda contents:
+                      self.failUnlessEqual(contents,
+                                           "contents of three/bar.txt\n"))
         return d
 
     def test_PUT_NEWDIRURL_localdir_disabled(self):
@@ -959,47 +909,41 @@ class Web(WebMixin, unittest.TestCase):
         d = self.PUT(self.public_url + "/foo/subdir/newdir?t=upload&localdir=%s"
                      % localdir,
                      "")
-        def _check(res):
-            self.failUnless(self._foo_node.fake_has_child("subdir"))
-            subnode = self._foo_node.fake_get("subdir")
-            self.failUnless(subnode.fake_has_child("newdir"))
-            newnode = subnode.fake_get("newdir")
-            self.failUnlessEqual(sorted(newnode.fake_list()),
-                                 sorted(["one", "two", "three", "zap.zip"]))
-            onenode = newnode.fake_get("one")
-            self.failUnlessEqual(sorted(onenode.fake_list()),
-                                 sorted(["sub"]))
-            threenode = newnode.fake_get("three")
-            self.failUnlessEqual(sorted(threenode.fake_list()),
-                                 sorted(["foo.txt", "bar.txt"]))
-            barnode = threenode.fake_get("bar.txt")
-            contents = self.files[barnode.get_uri()]
-            self.failUnlessEqual(contents, "contents of three/bar.txt\n")
-        d.addCallback(_check)
+        fn = self._foo_node
+        d.addCallback(lambda res: self.failUnlessNodeHasChild(fn, "subdir"))
+        d.addCallback(lambda res: fn.get_child_at_path("subdir/newdir"))
+        d.addCallback(self.failUnlessNodeKeysAre,
+                      ["one", "two", "three", "zap.zip"])
+        d.addCallback(lambda res: fn.get_child_at_path("subdir/newdir/one"))
+        d.addCallback(self.failUnlessNodeKeysAre, ["sub"])
+        d.addCallback(lambda res: fn.get_child_at_path("subdir/newdir/three"))
+        d.addCallback(self.failUnlessNodeKeysAre, ["foo.txt", "bar.txt"])
+        d.addCallback(lambda res:
+                      fn.get_child_at_path("subdir/newdir/three/bar.txt"))
+        d.addCallback(lambda barnode: barnode.download_to_data())
+        d.addCallback(lambda contents:
+                      self.failUnlessEqual(contents,
+                                           "contents of three/bar.txt\n"))
         return d
 
     def test_POST_upload(self):
         d = self.POST(self.public_url + "/foo", t="upload",
                       file=("new.txt", self.NEWFILE_CONTENTS))
-        def _check(res):
-            self.failUnless(self._foo_node.fake_has_child("new.txt"))
-            new_node = self._foo_node.fake_get("new.txt")
-            new_contents = self.files[new_node.get_uri()]
-            self.failUnlessEqual(new_contents, self.NEWFILE_CONTENTS)
-            self.failUnlessEqual(res.strip(), new_node.get_uri())
-        d.addCallback(_check)
+        fn = self._foo_node
+        d.addCallback(self.failUnlessURIMatchesChild, fn, "new.txt")
+        d.addCallback(lambda res:
+                      self.failUnlessChildContentsAre(fn, "new.txt",
+                                                      self.NEWFILE_CONTENTS))
         return d
 
     def test_POST_upload_replace(self):
         d = self.POST(self.public_url + "/foo", t="upload",
                       file=("bar.txt", self.NEWFILE_CONTENTS))
-        def _check(res):
-            self.failUnless(self._foo_node.fake_has_child("bar.txt"))
-            new_node = self._foo_node.fake_get("bar.txt")
-            new_contents = self.files[new_node.get_uri()]
-            self.failUnlessEqual(new_contents, self.NEWFILE_CONTENTS)
-            self.failUnlessEqual(res.strip(), new_node.get_uri())
-        d.addCallback(_check)
+        fn = self._foo_node
+        d.addCallback(self.failUnlessURIMatchesChild, fn, "bar.txt")
+        d.addCallback(lambda res:
+                      self.failUnlessChildContentsAre(fn, "bar.txt",
+                                                      self.NEWFILE_CONTENTS))
         return d
 
     def test_POST_upload_no_replace_queryarg(self):
@@ -1029,24 +973,20 @@ class Web(WebMixin, unittest.TestCase):
         d = self.POST(self.public_url + "/foo", t="upload", when_done="/THERE",
                       file=("new.txt", self.NEWFILE_CONTENTS))
         d.addBoth(self.shouldRedirect, "/THERE")
-        def _check(res):
-            self.failUnless(self._foo_node.fake_has_child("new.txt"))
-            new_node = self._foo_node.fake_get("new.txt")
-            new_contents = self.files[new_node.get_uri()]
-            self.failUnlessEqual(new_contents, self.NEWFILE_CONTENTS)
-        d.addCallback(_check)
+        fn = self._foo_node
+        d.addCallback(lambda res:
+                      self.failUnlessChildContentsAre(fn, "new.txt",
+                                                      self.NEWFILE_CONTENTS))
         return d
 
     def test_POST_upload_named(self):
+        fn = self._foo_node
         d = self.POST(self.public_url + "/foo", t="upload",
                       name="new.txt", file=self.NEWFILE_CONTENTS)
-        def _check(res):
-            self.failUnless(self._foo_node.fake_has_child("new.txt"))
-            new_node = self._foo_node.fake_get("new.txt")
-            new_contents = self.files[new_node.get_uri()]
-            self.failUnlessEqual(new_contents, self.NEWFILE_CONTENTS)
-            self.failUnlessEqual(res.strip(), new_node.get_uri())
-        d.addCallback(_check)
+        d.addCallback(self.failUnlessURIMatchesChild, fn, "new.txt")
+        d.addCallback(lambda res:
+                      self.failUnlessChildContentsAre(fn, "new.txt",
+                                                      self.NEWFILE_CONTENTS))
         return d
 
     def test_POST_upload_named_badfilename(self):
@@ -1057,31 +997,23 @@ class Web(WebMixin, unittest.TestCase):
                   "400 Bad Request",
                   "name= may not contain a slash",
                   )
-        def _check(res):
-            # make sure that nothing was added
-            kids = sorted(self._foo_node.fake_list())
-            self.failUnlessEqual(sorted(["bar.txt", "blockingfile",
-                                         "empty", "sub"]),
-                                 kids)
-        d.addCallback(_check)
+        # make sure that nothing was added
+        d.addCallback(lambda res:
+                      self.failUnlessNodeKeysAre(self._foo_node,
+                                                 ["bar.txt", "blockingfile",
+                                                  "empty", "sub"]))
         return d
 
     def test_POST_mkdir(self): # return value?
         d = self.POST(self.public_url + "/foo", t="mkdir", name="newdir")
-        def _check(res):
-            self.failUnless(self._foo_node.fake_has_child("newdir"))
-            newdir_node = self._foo_node.fake_get("newdir")
-            self.failIf(newdir_node.fake_list())
-        d.addCallback(_check)
+        d.addCallback(lambda res: self._foo_node.get("newdir"))
+        d.addCallback(self.failUnlessNodeKeysAre, [])
         return d
 
     def test_POST_mkdir_replace(self): # return value?
         d = self.POST(self.public_url + "/foo", t="mkdir", name="sub")
-        def _check(res):
-            self.failUnless(self._foo_node.fake_has_child("sub"))
-            newdir_node = self._foo_node.fake_get("sub")
-            self.failIf(newdir_node.fake_list())
-        d.addCallback(_check)
+        d.addCallback(lambda res: self._foo_node.get("sub"))
+        d.addCallback(self.failUnlessNodeKeysAre, [])
         return d
 
     def test_POST_mkdir_no_replace_queryarg(self): # return value?
@@ -1091,11 +1023,8 @@ class Web(WebMixin, unittest.TestCase):
                   "409 Conflict",
                   "There was already a child by that name, and you asked me "
                   "to not replace it")
-        def _check(res):
-            self.failUnless(self._foo_node.fake_has_child("sub"))
-            newdir_node = self._foo_node.fake_get("sub")
-            self.failUnlessEqual(newdir_node.fake_list().keys(), ["baz.txt"])
-        d.addCallback(_check)
+        d.addCallback(lambda res: self._foo_node.get("sub"))
+        d.addCallback(self.failUnlessNodeKeysAre, ["baz.txt"])
         return d
 
     def test_POST_mkdir_no_replace_field(self): # return value?
@@ -1105,64 +1034,46 @@ class Web(WebMixin, unittest.TestCase):
                   "409 Conflict",
                   "There was already a child by that name, and you asked me "
                   "to not replace it")
-        def _check(res):
-            self.failUnless(self._foo_node.fake_has_child("sub"))
-            newdir_node = self._foo_node.fake_get("sub")
-            self.failUnlessEqual(newdir_node.fake_list().keys(), ["baz.txt"])
-        d.addCallback(_check)
+        d.addCallback(lambda res: self._foo_node.get("sub"))
+        d.addCallback(self.failUnlessNodeKeysAre, ["baz.txt"])
         return d
 
     def test_POST_mkdir_whendone_field(self):
         d = self.POST(self.public_url + "/foo",
                       t="mkdir", name="newdir", when_done="/THERE")
         d.addBoth(self.shouldRedirect, "/THERE")
-        def _check(res):
-            self.failUnless(self._foo_node.fake_has_child("newdir"))
-            newdir_node = self._foo_node.fake_get("newdir")
-            self.failIf(newdir_node.fake_list())
-        d.addCallback(_check)
+        d.addCallback(lambda res: self._foo_node.get("newdir"))
+        d.addCallback(self.failUnlessNodeKeysAre, [])
         return d
 
     def test_POST_mkdir_whendone_queryarg(self):
         d = self.POST(self.public_url + "/foo?when_done=/THERE",
                       t="mkdir", name="newdir")
         d.addBoth(self.shouldRedirect, "/THERE")
-        def _check(res):
-            self.failUnless(self._foo_node.fake_has_child("newdir"))
-            newdir_node = self._foo_node.fake_get("newdir")
-            self.failIf(newdir_node.fake_list())
-        d.addCallback(_check)
+        d.addCallback(lambda res: self._foo_node.get("newdir"))
+        d.addCallback(self.failUnlessNodeKeysAre, [])
         return d
 
     def test_POST_put_uri(self):
-        newuri = self.makefile(8)
-        contents = self.files[newuri]
+        contents, n, newuri = self.makefile(8)
         d = self.POST(self.public_url + "/foo", t="uri", name="new.txt", uri=newuri)
-        def _check(res):
-            self.failUnless(self._foo_node.fake_has_child("new.txt"))
-            new_node = self._foo_node.fake_get("new.txt")
-            new_contents = self.files[new_node.get_uri()]
-            self.failUnlessEqual(new_contents, contents)
-            self.failUnlessEqual(res.strip(), new_node.get_uri())
-        d.addCallback(_check)
+        d.addCallback(self.failUnlessURIMatchesChild, self._foo_node, "new.txt")
+        d.addCallback(lambda res:
+                      self.failUnlessChildContentsAre(self._foo_node, "new.txt",
+                                                      contents))
         return d
 
     def test_POST_put_uri_replace(self):
-        newuri = self.makefile(8)
-        contents = self.files[newuri]
+        contents, n, newuri = self.makefile(8)
         d = self.POST(self.public_url + "/foo", t="uri", name="bar.txt", uri=newuri)
-        def _check(res):
-            self.failUnless(self._foo_node.fake_has_child("bar.txt"))
-            new_node = self._foo_node.fake_get("bar.txt")
-            new_contents = self.files[new_node.get_uri()]
-            self.failUnlessEqual(new_contents, contents)
-            self.failUnlessEqual(res.strip(), new_node.get_uri())
-        d.addCallback(_check)
+        d.addCallback(self.failUnlessURIMatchesChild, self._foo_node, "bar.txt")
+        d.addCallback(lambda res:
+                      self.failUnlessChildContentsAre(self._foo_node, "bar.txt",
+                                                      contents))
         return d
 
     def test_POST_put_uri_no_replace_queryarg(self):
-        newuri = self.makefile(8)
-        contents = self.files[newuri]
+        contents, n, newuri = self.makefile(8)
         d = self.POST(self.public_url + "/foo?replace=false", t="uri",
                       name="bar.txt", uri=newuri)
         d.addBoth(self.shouldFail, error.Error,
@@ -1175,8 +1086,7 @@ class Web(WebMixin, unittest.TestCase):
         return d
 
     def test_POST_put_uri_no_replace_field(self):
-        newuri = self.makefile(8)
-        contents = self.files[newuri]
+        contents, n, newuri = self.makefile(8)
         d = self.POST(self.public_url + "/foo", t="uri", replace="false",
                       name="bar.txt", uri=newuri)
         d.addBoth(self.shouldFail, error.Error,
@@ -1190,18 +1100,19 @@ class Web(WebMixin, unittest.TestCase):
 
     def test_POST_delete(self):
         d = self.POST(self.public_url + "/foo", t="delete", name="bar.txt")
-        def _check(res):
-            self.failIf(self._foo_node.fake_has_child("bar.txt"))
+        d.addCallback(lambda res: self._foo_node.list())
+        def _check(children):
+            self.failIf("bar.txt" in children)
         d.addCallback(_check)
         return d
 
     def test_POST_rename_file(self):
         d = self.POST(self.public_url + "/foo", t="rename",
                       from_name="bar.txt", to_name='wibble.txt')
-        def _check(res):
-            self.failIf(self._foo_node.fake_has_child("bar.txt"))
-            self.failUnless(self._foo_node.fake_has_child("wibble.txt"))
-        d.addCallback(_check)
+        d.addCallback(lambda res:
+                      self.failIfNodeHasChild(self._foo_node, "bar.txt"))
+        d.addCallback(lambda res:
+                      self.failUnlessNodeHasChild(self._foo_node, "wibble.txt"))
         d.addCallback(lambda res: self.GET(self.public_url + "/foo/wibble.txt"))
         d.addCallback(self.failUnlessIsBarDotTxt)
         d.addCallback(lambda res: self.GET(self.public_url + "/foo/wibble.txt?t=json"))
@@ -1212,10 +1123,10 @@ class Web(WebMixin, unittest.TestCase):
         # rename a file and replace a directory with it
         d = self.POST(self.public_url + "/foo", t="rename",
                       from_name="bar.txt", to_name='empty')
-        def _check(res):
-            self.failIf(self._foo_node.fake_has_child("bar.txt"))
-            self.failUnless(self._foo_node.fake_has_child("empty"))
-        d.addCallback(_check)
+        d.addCallback(lambda res:
+                      self.failIfNodeHasChild(self._foo_node, "bar.txt"))
+        d.addCallback(lambda res:
+                      self.failUnlessNodeHasChild(self._foo_node, "empty"))
         d.addCallback(lambda res: self.GET(self.public_url + "/foo/empty"))
         d.addCallback(self.failUnlessIsBarDotTxt)
         d.addCallback(lambda res: self.GET(self.public_url + "/foo/empty?t=json"))
@@ -1261,9 +1172,8 @@ class Web(WebMixin, unittest.TestCase):
                   "400 Bad Request",
                   "to_name= may not contain a slash",
                   )
-        def _check1(res):
-            self.failUnless(self._foo_node.fake_has_child("bar.txt"))
-        d.addCallback(_check1)
+        d.addCallback(lambda res:
+                      self.failUnlessNodeHasChild(self._foo_node, "bar.txt"))
         d.addCallback(lambda res: self.POST(self.public_url, t="rename",
                       from_name="foo/bar.txt", to_name='george.txt'))
         d.addBoth(self.shouldFail, error.Error,
@@ -1271,11 +1181,12 @@ class Web(WebMixin, unittest.TestCase):
                   "400 Bad Request",
                   "from_name= may not contain a slash",
                   )
-        def _check2(res):
-            self.failUnless(self.public_root.fake_has_child("foo"))
-            self.failIf(self.public_root.fake_has_child("george.txt"))
-            self.failUnless(self._foo_node.fake_has_child("bar.txt"))
-        d.addCallback(_check2)
+        d.addCallback(lambda res:
+                      self.failUnlessNodeHasChild(self.public_root, "foo"))
+        d.addCallback(lambda res:
+                      self.failIfNodeHasChild(self.public_root, "george.txt"))
+        d.addCallback(lambda res:
+                      self.failUnlessNodeHasChild(self._foo_node, "bar.txt"))
         d.addCallback(lambda res: self.GET(self.public_url + "/foo?t=json"))
         d.addCallback(self.failUnlessIsFooJSON)
         return d
@@ -1283,10 +1194,10 @@ class Web(WebMixin, unittest.TestCase):
     def test_POST_rename_dir(self):
         d = self.POST(self.public_url, t="rename",
                       from_name="foo", to_name='plunk')
-        def _check(res):
-            self.failIf(self.public_root.fake_has_child("foo"))
-            self.failUnless(self.public_root.fake_has_child("plunk"))
-        d.addCallback(_check)
+        d.addCallback(lambda res:
+                      self.failIfNodeHasChild(self.public_root, "foo"))
+        d.addCallback(lambda res:
+                      self.failUnlessNodeHasChild(self.public_root, "plunk"))
         d.addCallback(lambda res: self.GET(self.public_url + "/plunk?t=json"))
         d.addCallback(self.failUnlessIsFooJSON)
         return d
@@ -1364,31 +1275,25 @@ class Web(WebMixin, unittest.TestCase):
         return d
 
     def test_PUT_NEWFILEURL_uri(self):
-        new_uri = self.makefile(8)
+        contents, n, new_uri = self.makefile(8)
         d = self.PUT(self.public_url + "/foo/new.txt?t=uri", new_uri)
-        def _check(res):
-            self.failUnless(self._foo_node.fake_has_child("new.txt"))
-            new_node = self._foo_node.fake_get("new.txt")
-            new_contents = self.files[new_node.get_uri()]
-            self.failUnlessEqual(new_contents, self.files[new_uri])
-            self.failUnlessEqual(res.strip(), new_uri)
-        d.addCallback(_check)
+        d.addCallback(lambda res: self.failUnlessEqual(res.strip(), new_uri))
+        d.addCallback(lambda res:
+                      self.failUnlessChildContentsAre(self._foo_node, "new.txt",
+                                                      contents))
         return d
 
     def test_PUT_NEWFILEURL_uri_replace(self):
-        new_uri = self.makefile(8)
+        contents, n, new_uri = self.makefile(8)
         d = self.PUT(self.public_url + "/foo/bar.txt?t=uri", new_uri)
-        def _check(res):
-            self.failUnless(self._foo_node.fake_has_child("bar.txt"))
-            new_node = self._foo_node.fake_get("bar.txt")
-            new_contents = self.files[new_node.get_uri()]
-            self.failUnlessEqual(new_contents, self.files[new_uri])
-            self.failUnlessEqual(res.strip(), new_uri)
-        d.addCallback(_check)
+        d.addCallback(lambda res: self.failUnlessEqual(res.strip(), new_uri))
+        d.addCallback(lambda res:
+                      self.failUnlessChildContentsAre(self._foo_node, "bar.txt",
+                                                      contents))
         return d
 
     def test_PUT_NEWFILEURL_uri_no_replace(self):
-        new_uri = self.makefile(8)
+        contents, n, new_uri = self.makefile(8)
         d = self.PUT(self.public_url + "/foo/bar.txt?t=uri&replace=false", new_uri)
         d.addBoth(self.shouldFail, error.Error, "PUT_NEWFILEURL_uri_no_replace",
                   "409 Conflict",
@@ -1400,8 +1305,9 @@ class Web(WebMixin, unittest.TestCase):
         file_contents = "New file contents here\n"
         d = self.PUT("/uri", file_contents)
         def _check(uri):
-            self.failUnless(uri in self.files)
-            self.failUnlessEqual(self.files[uri], file_contents)
+            self.failUnless(uri in FakeCHKFileNode.all_contents)
+            self.failUnlessEqual(FakeCHKFileNode.all_contents[uri],
+                                 file_contents)
             return self.GET("/uri/%s" % uri.replace("/","!"))
         d.addCallback(_check)
         def _check2(res):
@@ -1420,9 +1326,11 @@ class Web(WebMixin, unittest.TestCase):
     def test_PUT_NEWDIR_URI(self):
         d = self.PUT("/uri?t=mkdir", "")
         def _check(uri):
-            self.failUnless(uri in self.nodes)
-            self.failUnless(isinstance(self.nodes[uri], FakeDirectoryNode))
-            return self.GET("/uri/%s?t=json" % uri.replace("/","!"))
+            n = self.s.create_node_from_uri(uri.strip())
+            d2 = self.failUnlessNodeKeysAre(n, [])
+            d2.addCallback(lambda res:
+                           self.GET("/uri/%s?t=json" % uri.replace("/","!")))
+            return d2
         d.addCallback(_check)
         d.addCallback(self.failUnlessIsEmptyJSON)
         return d