view mercurial/testing/storage.py @ 39776:cb65d4b7e429

error: introduce StorageError

Errors in revlogs are often represented by RevlogError. It's fine
for revlogs to raise a revlog-specific exception. But in the context
of multiple storage backends, it doesn't make sense to be throwing or
catching an exception with "revlog" in its name when revlogs may not
even be in play.

This commit introduces a new generic StorageError type for representing
errors in the storage layer.

RevlogError is an instance of this type.

Interface documentation and tests referencing RevlogError has been
updated to specify StorageError should be used.

.. api::

   ``error.StorageError`` has been introduced to represent errors in
   storage. It should be used in place of ``error.RevlogError`` unless
   the error is known to come from a revlog.

Differential Revision: https://phab.mercurial-scm.org/D4654

# storage.py - Testing of storage primitives.
#
# Copyright 2018 Gregory Szorc <[e-mail]>
#
# This software may be used and distributed according to the terms of the
# GNU General Public License version 2 or any later version.

from __future__ import absolute_import

import unittest

from ..node import (
    hex,
    nullid,
    nullrev,
)
from .. import (
    error,
    mdiff,
    revlog,
)

class basetestcase(unittest.TestCase):
    if not getattr(unittest.TestCase, r'assertRaisesRegex', False):
        assertRaisesRegex = (# camelcase-required
            unittest.TestCase.assertRaisesRegexp)

class revisiondeltarequest(object):
    def __init__(self, node, p1, p2, linknode, basenode, ellipsis):
        self.node = node
        self.p1node = p1
        self.p2node = p2
        self.linknode = linknode
        self.basenode = basenode
        self.ellipsis = ellipsis

class ifileindextests(basetestcase):
    """Generic tests for the ifileindex interface.

    All file storage backends for index data should conform to the tests in this
    class.

    Use ``makeifileindextests()`` to create an instance of this type.
    """
    def testempty(self):
        f = self._makefilefn()
        self.assertEqual(len(f), 0, 'new file store has 0 length by default')
        self.assertEqual(list(f), [], 'iter yields nothing by default')

        gen = iter(f)
        with self.assertRaises(StopIteration):
            next(gen)

        # revs() should evaluate to an empty list.
        self.assertEqual(list(f.revs()), [])

        revs = iter(f.revs())
        with self.assertRaises(StopIteration):
            next(revs)

        self.assertEqual(list(f.revs(start=20)), [])

        # parents() and parentrevs() work with nullid/nullrev.
        self.assertEqual(f.parents(nullid), (nullid, nullid))
        self.assertEqual(f.parentrevs(nullrev), (nullrev, nullrev))

        with self.assertRaises(error.LookupError):
            f.parents(b'\x01' * 20)

        for i in range(-5, 5):
            if i == nullrev:
                continue

            with self.assertRaises(IndexError):
                f.parentrevs(i)

        # nullid/nullrev lookup always works.
        self.assertEqual(f.rev(nullid), nullrev)
        self.assertEqual(f.node(nullrev), nullid)

        with self.assertRaises(error.LookupError):
            f.rev(b'\x01' * 20)

        for i in range(-5, 5):
            if i == nullrev:
                continue

            with self.assertRaises(IndexError):
                f.node(i)

        self.assertEqual(f.lookup(nullid), nullid)
        self.assertEqual(f.lookup(nullrev), nullid)
        self.assertEqual(f.lookup(hex(nullid)), nullid)

        # String converted to integer doesn't work for nullrev.
        with self.assertRaises(error.LookupError):
            f.lookup(b'%d' % nullrev)

        self.assertEqual(f.linkrev(nullrev), nullrev)

        for i in range(-5, 5):
            if i == nullrev:
                continue

            with self.assertRaises(IndexError):
                f.linkrev(i)

        self.assertEqual(f.flags(nullrev), 0)

        for i in range(-5, 5):
            if i == nullrev:
                continue

            with self.assertRaises(IndexError):
                f.flags(i)

        self.assertFalse(f.iscensored(nullrev))

        for i in range(-5, 5):
            if i == nullrev:
                continue

            with self.assertRaises(IndexError):
                f.iscensored(i)

        self.assertEqual(list(f.commonancestorsheads(nullid, nullid)), [])

        with self.assertRaises(ValueError):
            self.assertEqual(list(f.descendants([])), [])

        self.assertEqual(list(f.descendants([nullrev])), [])

        self.assertEqual(f.headrevs(), [nullrev])
        self.assertEqual(f.heads(), [nullid])
        self.assertEqual(f.heads(nullid), [nullid])
        self.assertEqual(f.heads(None, [nullid]), [nullid])
        self.assertEqual(f.heads(nullid, [nullid]), [nullid])

        self.assertEqual(f.children(nullid), [])

        with self.assertRaises(error.LookupError):
            f.children(b'\x01' * 20)

        self.assertEqual(f.deltaparent(nullrev), nullrev)

        for i in range(-5, 5):
            if i == nullrev:
                continue

            with self.assertRaises(IndexError):
                f.deltaparent(i)

    def testsinglerevision(self):
        f = self._makefilefn()
        with self._maketransactionfn() as tr:
            node = f.add(b'initial', None, tr, 0, nullid, nullid)

        self.assertEqual(len(f), 1)
        self.assertEqual(list(f), [0])

        gen = iter(f)
        self.assertEqual(next(gen), 0)

        with self.assertRaises(StopIteration):
            next(gen)

        self.assertEqual(list(f.revs()), [0])
        self.assertEqual(list(f.revs(start=1)), [])
        self.assertEqual(list(f.revs(start=0)), [0])
        self.assertEqual(list(f.revs(stop=0)), [0])
        self.assertEqual(list(f.revs(stop=1)), [0])
        self.assertEqual(list(f.revs(1, 1)), [])
        # TODO buggy
        self.assertEqual(list(f.revs(1, 0)), [1, 0])
        self.assertEqual(list(f.revs(2, 0)), [2, 1, 0])

        self.assertEqual(f.parents(node), (nullid, nullid))
        self.assertEqual(f.parentrevs(0), (nullrev, nullrev))

        with self.assertRaises(error.LookupError):
            f.parents(b'\x01' * 20)

        with self.assertRaises(IndexError):
            f.parentrevs(1)

        self.assertEqual(f.rev(node), 0)

        with self.assertRaises(error.LookupError):
            f.rev(b'\x01' * 20)

        self.assertEqual(f.node(0), node)

        with self.assertRaises(IndexError):
            f.node(1)

        self.assertEqual(f.lookup(node), node)
        self.assertEqual(f.lookup(0), node)
        self.assertEqual(f.lookup(b'0'), node)
        self.assertEqual(f.lookup(hex(node)), node)

        self.assertEqual(f.linkrev(0), 0)

        with self.assertRaises(IndexError):
            f.linkrev(1)

        self.assertEqual(f.flags(0), 0)

        with self.assertRaises(IndexError):
            f.flags(1)

        self.assertFalse(f.iscensored(0))

        with self.assertRaises(IndexError):
            f.iscensored(1)

        self.assertEqual(list(f.descendants([0])), [])

        self.assertEqual(f.headrevs(), [0])

        self.assertEqual(f.heads(), [node])
        self.assertEqual(f.heads(node), [node])
        self.assertEqual(f.heads(stop=[node]), [node])

        with self.assertRaises(error.LookupError):
            f.heads(stop=[b'\x01' * 20])

        self.assertEqual(f.children(node), [])

        self.assertEqual(f.deltaparent(0), nullrev)

    def testmultiplerevisions(self):
        fulltext0 = b'x' * 1024
        fulltext1 = fulltext0 + b'y'
        fulltext2 = b'y' + fulltext0 + b'z'

        f = self._makefilefn()
        with self._maketransactionfn() as tr:
            node0 = f.add(fulltext0, None, tr, 0, nullid, nullid)
            node1 = f.add(fulltext1, None, tr, 1, node0, nullid)
            node2 = f.add(fulltext2, None, tr, 3, node1, nullid)

        self.assertEqual(len(f), 3)
        self.assertEqual(list(f), [0, 1, 2])

        gen = iter(f)
        self.assertEqual(next(gen), 0)
        self.assertEqual(next(gen), 1)
        self.assertEqual(next(gen), 2)

        with self.assertRaises(StopIteration):
            next(gen)

        self.assertEqual(list(f.revs()), [0, 1, 2])
        self.assertEqual(list(f.revs(0)), [0, 1, 2])
        self.assertEqual(list(f.revs(1)), [1, 2])
        self.assertEqual(list(f.revs(2)), [2])
        self.assertEqual(list(f.revs(3)), [])
        self.assertEqual(list(f.revs(stop=1)), [0, 1])
        self.assertEqual(list(f.revs(stop=2)), [0, 1, 2])
        self.assertEqual(list(f.revs(stop=3)), [0, 1, 2])
        self.assertEqual(list(f.revs(2, 0)), [2, 1, 0])
        self.assertEqual(list(f.revs(2, 1)), [2, 1])
        # TODO this is wrong
        self.assertEqual(list(f.revs(3, 2)), [3, 2])

        self.assertEqual(f.parents(node0), (nullid, nullid))
        self.assertEqual(f.parents(node1), (node0, nullid))
        self.assertEqual(f.parents(node2), (node1, nullid))

        self.assertEqual(f.parentrevs(0), (nullrev, nullrev))
        self.assertEqual(f.parentrevs(1), (0, nullrev))
        self.assertEqual(f.parentrevs(2), (1, nullrev))

        self.assertEqual(f.rev(node0), 0)
        self.assertEqual(f.rev(node1), 1)
        self.assertEqual(f.rev(node2), 2)

        with self.assertRaises(error.LookupError):
            f.rev(b'\x01' * 20)

        self.assertEqual(f.node(0), node0)
        self.assertEqual(f.node(1), node1)
        self.assertEqual(f.node(2), node2)

        with self.assertRaises(IndexError):
            f.node(3)

        self.assertEqual(f.lookup(node0), node0)
        self.assertEqual(f.lookup(0), node0)
        self.assertEqual(f.lookup(b'0'), node0)
        self.assertEqual(f.lookup(hex(node0)), node0)

        self.assertEqual(f.lookup(node1), node1)
        self.assertEqual(f.lookup(1), node1)
        self.assertEqual(f.lookup(b'1'), node1)
        self.assertEqual(f.lookup(hex(node1)), node1)

        self.assertEqual(f.linkrev(0), 0)
        self.assertEqual(f.linkrev(1), 1)
        self.assertEqual(f.linkrev(2), 3)

        with self.assertRaises(IndexError):
            f.linkrev(3)

        self.assertEqual(f.flags(0), 0)
        self.assertEqual(f.flags(1), 0)
        self.assertEqual(f.flags(2), 0)

        with self.assertRaises(IndexError):
            f.flags(3)

        self.assertFalse(f.iscensored(0))
        self.assertFalse(f.iscensored(1))
        self.assertFalse(f.iscensored(2))

        with self.assertRaises(IndexError):
            f.iscensored(3)

        self.assertEqual(f.commonancestorsheads(node1, nullid), [])
        self.assertEqual(f.commonancestorsheads(node1, node0), [node0])
        self.assertEqual(f.commonancestorsheads(node1, node1), [node1])
        self.assertEqual(f.commonancestorsheads(node0, node1), [node0])
        self.assertEqual(f.commonancestorsheads(node1, node2), [node1])
        self.assertEqual(f.commonancestorsheads(node2, node1), [node1])

        self.assertEqual(list(f.descendants([0])), [1, 2])
        self.assertEqual(list(f.descendants([1])), [2])
        self.assertEqual(list(f.descendants([0, 1])), [1, 2])

        self.assertEqual(f.headrevs(), [2])

        self.assertEqual(f.heads(), [node2])
        self.assertEqual(f.heads(node0), [node2])
        self.assertEqual(f.heads(node1), [node2])
        self.assertEqual(f.heads(node2), [node2])

        # TODO this behavior seems wonky. Is it correct? If so, the
        # docstring for heads() should be updated to reflect desired
        # behavior.
        self.assertEqual(f.heads(stop=[node1]), [node1, node2])
        self.assertEqual(f.heads(stop=[node0]), [node0, node2])
        self.assertEqual(f.heads(stop=[node1, node2]), [node1, node2])

        with self.assertRaises(error.LookupError):
            f.heads(stop=[b'\x01' * 20])

        self.assertEqual(f.children(node0), [node1])
        self.assertEqual(f.children(node1), [node2])
        self.assertEqual(f.children(node2), [])

        self.assertEqual(f.deltaparent(0), nullrev)
        self.assertEqual(f.deltaparent(1), 0)
        self.assertEqual(f.deltaparent(2), 1)

    def testmultipleheads(self):
        f = self._makefilefn()

        with self._maketransactionfn() as tr:
            node0 = f.add(b'0', None, tr, 0, nullid, nullid)
            node1 = f.add(b'1', None, tr, 1, node0, nullid)
            node2 = f.add(b'2', None, tr, 2, node1, nullid)
            node3 = f.add(b'3', None, tr, 3, node0, nullid)
            node4 = f.add(b'4', None, tr, 4, node3, nullid)
            node5 = f.add(b'5', None, tr, 5, node0, nullid)

        self.assertEqual(len(f), 6)

        self.assertEqual(list(f.descendants([0])), [1, 2, 3, 4, 5])
        self.assertEqual(list(f.descendants([1])), [2])
        self.assertEqual(list(f.descendants([2])), [])
        self.assertEqual(list(f.descendants([3])), [4])
        self.assertEqual(list(f.descendants([0, 1])), [1, 2, 3, 4, 5])
        self.assertEqual(list(f.descendants([1, 3])), [2, 4])

        self.assertEqual(f.headrevs(), [2, 4, 5])

        self.assertEqual(f.heads(), [node2, node4, node5])
        self.assertEqual(f.heads(node0), [node2, node4, node5])
        self.assertEqual(f.heads(node1), [node2])
        self.assertEqual(f.heads(node2), [node2])
        self.assertEqual(f.heads(node3), [node4])
        self.assertEqual(f.heads(node4), [node4])
        self.assertEqual(f.heads(node5), [node5])

        # TODO this seems wrong.
        self.assertEqual(f.heads(stop=[node0]), [node0, node2, node4, node5])
        self.assertEqual(f.heads(stop=[node1]), [node1, node2, node4, node5])

        self.assertEqual(f.children(node0), [node1, node3, node5])
        self.assertEqual(f.children(node1), [node2])
        self.assertEqual(f.children(node2), [])
        self.assertEqual(f.children(node3), [node4])
        self.assertEqual(f.children(node4), [])
        self.assertEqual(f.children(node5), [])

class ifiledatatests(basetestcase):
    """Generic tests for the ifiledata interface.

    All file storage backends for data should conform to the tests in this
    class.

    Use ``makeifiledatatests()`` to create an instance of this type.
    """
    def testempty(self):
        f = self._makefilefn()

        self.assertEqual(f.rawsize(nullrev), 0)

        for i in range(-5, 5):
            if i == nullrev:
                continue

            with self.assertRaises(IndexError):
                f.rawsize(i)

        self.assertEqual(f.size(nullrev), 0)

        for i in range(-5, 5):
            if i == nullrev:
                continue

            with self.assertRaises(IndexError):
                f.size(i)

        with self.assertRaises(error.StorageError):
            f.checkhash(b'', nullid)

        with self.assertRaises(error.LookupError):
            f.checkhash(b'', b'\x01' * 20)

        self.assertEqual(f.revision(nullid), b'')
        self.assertEqual(f.revision(nullid, raw=True), b'')

        with self.assertRaises(error.LookupError):
            f.revision(b'\x01' * 20)

        self.assertEqual(f.read(nullid), b'')

        with self.assertRaises(error.LookupError):
            f.read(b'\x01' * 20)

        self.assertFalse(f.renamed(nullid))

        with self.assertRaises(error.LookupError):
            f.read(b'\x01' * 20)

        self.assertTrue(f.cmp(nullid, b''))
        self.assertTrue(f.cmp(nullid, b'foo'))

        with self.assertRaises(error.LookupError):
            f.cmp(b'\x01' * 20, b'irrelevant')

        self.assertEqual(f.revdiff(nullrev, nullrev), b'')

        with self.assertRaises(IndexError):
            f.revdiff(0, nullrev)

        with self.assertRaises(IndexError):
            f.revdiff(nullrev, 0)

        with self.assertRaises(IndexError):
            f.revdiff(0, 0)

        gen = f.emitrevisiondeltas([])
        with self.assertRaises(StopIteration):
            next(gen)

        requests = [
            revisiondeltarequest(nullid, nullid, nullid, nullid, nullid, False),
        ]
        gen = f.emitrevisiondeltas(requests)

        delta = next(gen)

        self.assertEqual(delta.node, nullid)
        self.assertEqual(delta.p1node, nullid)
        self.assertEqual(delta.p2node, nullid)
        self.assertEqual(delta.linknode, nullid)
        self.assertEqual(delta.basenode, nullid)
        self.assertIsNone(delta.baserevisionsize)
        self.assertEqual(delta.revision, b'')
        self.assertIsNone(delta.delta)

        with self.assertRaises(StopIteration):
            next(gen)

        requests = [
            revisiondeltarequest(nullid, nullid, nullid, nullid, nullid, False),
            revisiondeltarequest(nullid, b'\x01' * 20, b'\x02' * 20,
                                 b'\x03' * 20, nullid, False)
        ]

        gen = f.emitrevisiondeltas(requests)

        next(gen)
        delta = next(gen)

        self.assertEqual(delta.node, nullid)
        self.assertEqual(delta.p1node, b'\x01' * 20)
        self.assertEqual(delta.p2node, b'\x02' * 20)
        self.assertEqual(delta.linknode, b'\x03' * 20)
        self.assertEqual(delta.basenode, nullid)
        self.assertIsNone(delta.baserevisionsize)
        self.assertEqual(delta.revision, b'')
        self.assertIsNone(delta.delta)

        with self.assertRaises(StopIteration):
            next(gen)

    def testsinglerevision(self):
        fulltext = b'initial'

        f = self._makefilefn()
        with self._maketransactionfn() as tr:
            node = f.add(fulltext, None, tr, 0, nullid, nullid)

        self.assertEqual(f.rawsize(0), len(fulltext))

        with self.assertRaises(IndexError):
            f.rawsize(1)

        self.assertEqual(f.size(0), len(fulltext))

        with self.assertRaises(IndexError):
            f.size(1)

        f.checkhash(fulltext, node)
        f.checkhash(fulltext, node, nullid, nullid)

        with self.assertRaises(error.StorageError):
            f.checkhash(fulltext + b'extra', node)

        with self.assertRaises(error.StorageError):
            f.checkhash(fulltext, node, b'\x01' * 20, nullid)

        with self.assertRaises(error.StorageError):
            f.checkhash(fulltext, node, nullid, b'\x01' * 20)

        self.assertEqual(f.revision(node), fulltext)
        self.assertEqual(f.revision(node, raw=True), fulltext)

        self.assertEqual(f.read(node), fulltext)

        self.assertFalse(f.renamed(node))

        self.assertFalse(f.cmp(node, fulltext))
        self.assertTrue(f.cmp(node, fulltext + b'extra'))

        self.assertEqual(f.revdiff(0, 0), b'')
        self.assertEqual(f.revdiff(nullrev, 0),
                         b'\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x07%s' %
                         fulltext)

        self.assertEqual(f.revdiff(0, nullrev),
                         b'\x00\x00\x00\x00\x00\x00\x00\x07\x00\x00\x00\x00')

        requests = [
            revisiondeltarequest(node, nullid, nullid, nullid, nullid, False),
        ]
        gen = f.emitrevisiondeltas(requests)

        delta = next(gen)

        self.assertEqual(delta.node, node)
        self.assertEqual(delta.p1node, nullid)
        self.assertEqual(delta.p2node, nullid)
        self.assertEqual(delta.linknode, nullid)
        self.assertEqual(delta.basenode, nullid)
        self.assertIsNone(delta.baserevisionsize)
        self.assertEqual(delta.revision, fulltext)
        self.assertIsNone(delta.delta)

        with self.assertRaises(StopIteration):
            next(gen)

    def testmultiplerevisions(self):
        fulltext0 = b'x' * 1024
        fulltext1 = fulltext0 + b'y'
        fulltext2 = b'y' + fulltext0 + b'z'

        f = self._makefilefn()
        with self._maketransactionfn() as tr:
            node0 = f.add(fulltext0, None, tr, 0, nullid, nullid)
            node1 = f.add(fulltext1, None, tr, 1, node0, nullid)
            node2 = f.add(fulltext2, None, tr, 3, node1, nullid)

        self.assertEqual(f.rawsize(0), len(fulltext0))
        self.assertEqual(f.rawsize(1), len(fulltext1))
        self.assertEqual(f.rawsize(2), len(fulltext2))

        with self.assertRaises(IndexError):
            f.rawsize(3)

        self.assertEqual(f.size(0), len(fulltext0))
        self.assertEqual(f.size(1), len(fulltext1))
        self.assertEqual(f.size(2), len(fulltext2))

        with self.assertRaises(IndexError):
            f.size(3)

        f.checkhash(fulltext0, node0)
        f.checkhash(fulltext1, node1)
        f.checkhash(fulltext1, node1, node0, nullid)
        f.checkhash(fulltext2, node2, node1, nullid)

        with self.assertRaises(error.StorageError):
            f.checkhash(fulltext1, b'\x01' * 20)

        with self.assertRaises(error.StorageError):
            f.checkhash(fulltext1 + b'extra', node1, node0, nullid)

        with self.assertRaises(error.StorageError):
            f.checkhash(fulltext1, node1, node0, node0)

        self.assertEqual(f.revision(node0), fulltext0)
        self.assertEqual(f.revision(node0, raw=True), fulltext0)
        self.assertEqual(f.revision(node1), fulltext1)
        self.assertEqual(f.revision(node1, raw=True), fulltext1)
        self.assertEqual(f.revision(node2), fulltext2)
        self.assertEqual(f.revision(node2, raw=True), fulltext2)

        with self.assertRaises(error.LookupError):
            f.revision(b'\x01' * 20)

        self.assertEqual(f.read(node0), fulltext0)
        self.assertEqual(f.read(node1), fulltext1)
        self.assertEqual(f.read(node2), fulltext2)

        with self.assertRaises(error.LookupError):
            f.read(b'\x01' * 20)

        self.assertFalse(f.renamed(node0))
        self.assertFalse(f.renamed(node1))
        self.assertFalse(f.renamed(node2))

        with self.assertRaises(error.LookupError):
            f.renamed(b'\x01' * 20)

        self.assertFalse(f.cmp(node0, fulltext0))
        self.assertFalse(f.cmp(node1, fulltext1))
        self.assertFalse(f.cmp(node2, fulltext2))

        self.assertTrue(f.cmp(node1, fulltext0))
        self.assertTrue(f.cmp(node2, fulltext1))

        with self.assertRaises(error.LookupError):
            f.cmp(b'\x01' * 20, b'irrelevant')

        self.assertEqual(f.revdiff(0, 1),
                         b'\x00\x00\x00\x00\x00\x00\x04\x00\x00\x00\x04\x01' +
                         fulltext1)

        self.assertEqual(f.revdiff(0, 2),
                         b'\x00\x00\x00\x00\x00\x00\x04\x00\x00\x00\x04\x02' +
                         fulltext2)

        requests = [
            revisiondeltarequest(node0, nullid, nullid, b'\x01' * 20, nullid,
                                 False),
            revisiondeltarequest(node1, node0, nullid, b'\x02' * 20, node0,
                                 False),
            revisiondeltarequest(node2, node1, nullid, b'\x03' * 20, node1,
                                 False),
        ]
        gen = f.emitrevisiondeltas(requests)

        delta = next(gen)

        self.assertEqual(delta.node, node0)
        self.assertEqual(delta.p1node, nullid)
        self.assertEqual(delta.p2node, nullid)
        self.assertEqual(delta.linknode, b'\x01' * 20)
        self.assertEqual(delta.basenode, nullid)
        self.assertIsNone(delta.baserevisionsize)
        self.assertEqual(delta.revision, fulltext0)
        self.assertIsNone(delta.delta)

        delta = next(gen)

        self.assertEqual(delta.node, node1)
        self.assertEqual(delta.p1node, node0)
        self.assertEqual(delta.p2node, nullid)
        self.assertEqual(delta.linknode, b'\x02' * 20)
        self.assertEqual(delta.basenode, node0)
        self.assertIsNone(delta.baserevisionsize)
        self.assertIsNone(delta.revision)
        self.assertEqual(delta.delta,
                         b'\x00\x00\x00\x00\x00\x00\x04\x00\x00\x00\x04\x01' +
                         fulltext1)

        delta = next(gen)

        self.assertEqual(delta.node, node2)
        self.assertEqual(delta.p1node, node1)
        self.assertEqual(delta.p2node, nullid)
        self.assertEqual(delta.linknode, b'\x03' * 20)
        self.assertEqual(delta.basenode, node1)
        self.assertIsNone(delta.baserevisionsize)
        self.assertIsNone(delta.revision)
        self.assertEqual(delta.delta,
                         b'\x00\x00\x00\x00\x00\x00\x04\x01\x00\x00\x04\x02' +
                         fulltext2)

        with self.assertRaises(StopIteration):
            next(gen)

    def testrenamed(self):
        fulltext0 = b'foo'
        fulltext1 = b'bar'
        fulltext2 = b'baz'

        meta1 = {
            b'copy': b'source0',
            b'copyrev': b'a' * 40,
        }

        meta2 = {
            b'copy': b'source1',
            b'copyrev': b'b' * 40,
        }

        stored1 = b''.join([
            b'\x01\ncopy: source0\n',
            b'copyrev: aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa\n\x01\n',
            fulltext1,
        ])

        stored2 = b''.join([
            b'\x01\ncopy: source1\n',
            b'copyrev: bbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbb\n\x01\n',
            fulltext2,
        ])

        f = self._makefilefn()
        with self._maketransactionfn() as tr:
            node0 = f.add(fulltext0, None, tr, 0, nullid, nullid)
            node1 = f.add(fulltext1, meta1, tr, 1, node0, nullid)
            node2 = f.add(fulltext2, meta2, tr, 2, nullid, nullid)

        self.assertEqual(f.rawsize(1), len(stored1))
        self.assertEqual(f.rawsize(2), len(stored2))

        # Metadata header isn't recognized when parent isn't nullid.
        self.assertEqual(f.size(1), len(stored1))
        self.assertEqual(f.size(2), len(fulltext2))

        self.assertEqual(f.revision(node1), stored1)
        self.assertEqual(f.revision(node1, raw=True), stored1)
        self.assertEqual(f.revision(node2), stored2)
        self.assertEqual(f.revision(node2, raw=True), stored2)

        self.assertEqual(f.read(node1), fulltext1)
        self.assertEqual(f.read(node2), fulltext2)

        # Returns False when first parent is set.
        self.assertFalse(f.renamed(node1))
        self.assertEqual(f.renamed(node2), (b'source1', b'\xbb' * 20))

        self.assertTrue(f.cmp(node1, fulltext1))
        self.assertTrue(f.cmp(node1, stored1))
        self.assertFalse(f.cmp(node2, fulltext2))
        self.assertTrue(f.cmp(node2, stored2))

    def testmetadataprefix(self):
        # Content with metadata prefix has extra prefix inserted in storage.
        fulltext0 = b'\x01\nfoo'
        stored0 = b'\x01\n\x01\n\x01\nfoo'

        fulltext1 = b'\x01\nbar'
        meta1 = {
            b'copy': b'source0',
            b'copyrev': b'b' * 40,
        }
        stored1 = b''.join([
            b'\x01\ncopy: source0\n',
            b'copyrev: %s\n' % (b'b' * 40),
            b'\x01\n\x01\nbar',
        ])

        f = self._makefilefn()
        with self._maketransactionfn() as tr:
            node0 = f.add(fulltext0, {}, tr, 0, nullid, nullid)
            node1 = f.add(fulltext1, meta1, tr, 1, nullid, nullid)

        self.assertEqual(f.rawsize(0), len(stored0))
        self.assertEqual(f.rawsize(1), len(stored1))

        # TODO this is buggy.
        self.assertEqual(f.size(0), len(fulltext0) + 4)

        self.assertEqual(f.size(1), len(fulltext1))

        self.assertEqual(f.revision(node0), stored0)
        self.assertEqual(f.revision(node0, raw=True), stored0)

        self.assertEqual(f.revision(node1), stored1)
        self.assertEqual(f.revision(node1, raw=True), stored1)

        self.assertEqual(f.read(node0), fulltext0)
        self.assertEqual(f.read(node1), fulltext1)

        self.assertFalse(f.cmp(node0, fulltext0))
        self.assertTrue(f.cmp(node0, stored0))

        self.assertFalse(f.cmp(node1, fulltext1))
        self.assertTrue(f.cmp(node1, stored0))

    def testcensored(self):
        f = self._makefilefn()

        stored1 = revlog.packmeta({
            b'censored': b'tombstone',
        }, b'')

        # TODO tests are incomplete because we need the node to be
        # different due to presence of censor metadata. But we can't
        # do this with addrevision().
        with self._maketransactionfn() as tr:
            node0 = f.add(b'foo', None, tr, 0, nullid, nullid)
            f.addrevision(stored1, tr, 1, node0, nullid,
                          flags=revlog.REVIDX_ISCENSORED)

        self.assertEqual(f.flags(1), revlog.REVIDX_ISCENSORED)
        self.assertTrue(f.iscensored(1))

        self.assertEqual(f.revision(1), stored1)
        self.assertEqual(f.revision(1, raw=True), stored1)

        self.assertEqual(f.read(1), b'')

class ifilemutationtests(basetestcase):
    """Generic tests for the ifilemutation interface.

    All file storage backends that support writing should conform to this
    interface.

    Use ``makeifilemutationtests()`` to create an instance of this type.
    """
    def testaddnoop(self):
        f = self._makefilefn()
        with self._maketransactionfn() as tr:
            node0 = f.add(b'foo', None, tr, 0, nullid, nullid)
            node1 = f.add(b'foo', None, tr, 0, nullid, nullid)
            # Varying by linkrev shouldn't impact hash.
            node2 = f.add(b'foo', None, tr, 1, nullid, nullid)

        self.assertEqual(node1, node0)
        self.assertEqual(node2, node0)
        self.assertEqual(len(f), 1)

    def testaddrevisionbadnode(self):
        f = self._makefilefn()
        with self._maketransactionfn() as tr:
            # Adding a revision with bad node value fails.
            with self.assertRaises(error.StorageError):
                f.addrevision(b'foo', tr, 0, nullid, nullid, node=b'\x01' * 20)

    def testaddrevisionunknownflag(self):
        f = self._makefilefn()
        with self._maketransactionfn() as tr:
            for i in range(15, 0, -1):
                if (1 << i) & ~revlog.REVIDX_KNOWN_FLAGS:
                    flags = 1 << i
                    break

            with self.assertRaises(error.StorageError):
                f.addrevision(b'foo', tr, 0, nullid, nullid, flags=flags)

    def testaddgroupsimple(self):
        f = self._makefilefn()

        callbackargs = []
        def cb(*args, **kwargs):
            callbackargs.append((args, kwargs))

        def linkmapper(node):
            return 0

        with self._maketransactionfn() as tr:
            nodes = f.addgroup([], None, tr, addrevisioncb=cb)

        self.assertEqual(nodes, [])
        self.assertEqual(callbackargs, [])
        self.assertEqual(len(f), 0)

        fulltext0 = b'foo'
        delta0 = mdiff.trivialdiffheader(len(fulltext0)) + fulltext0

        deltas = [
            (b'\x01' * 20, nullid, nullid, nullid, nullid, delta0, 0),
        ]

        with self._maketransactionfn() as tr:
            with self.assertRaises(error.StorageError):
                f.addgroup(deltas, linkmapper, tr, addrevisioncb=cb)

            node0 = f.add(fulltext0, None, tr, 0, nullid, nullid)

        f = self._makefilefn()

        deltas = [
            (node0, nullid, nullid, nullid, nullid, delta0, 0),
        ]

        with self._maketransactionfn() as tr:
            nodes = f.addgroup(deltas, linkmapper, tr, addrevisioncb=cb)

        self.assertEqual(nodes, [
            b'\x49\xd8\xcb\xb1\x5c\xe2\x57\x92\x04\x47'
            b'\x00\x6b\x46\x97\x8b\x7a\xf9\x80\xa9\x79'])

        self.assertEqual(len(callbackargs), 1)
        self.assertEqual(callbackargs[0][0][1], nodes[0])

        self.assertEqual(list(f.revs()), [0])
        self.assertEqual(f.rev(nodes[0]), 0)
        self.assertEqual(f.node(0), nodes[0])

    def testaddgroupmultiple(self):
        f = self._makefilefn()

        fulltexts = [
            b'foo',
            b'bar',
            b'x' * 1024,
        ]

        nodes = []
        with self._maketransactionfn() as tr:
            for fulltext in fulltexts:
                nodes.append(f.add(fulltext, None, tr, 0, nullid, nullid))

        f = self._makefilefn()
        deltas = []
        for i, fulltext in enumerate(fulltexts):
            delta = mdiff.trivialdiffheader(len(fulltext)) + fulltext

            deltas.append((nodes[i], nullid, nullid, nullid, nullid, delta, 0))

        with self._maketransactionfn() as tr:
            self.assertEqual(f.addgroup(deltas, lambda x: 0, tr), nodes)

        self.assertEqual(len(f), len(deltas))
        self.assertEqual(list(f.revs()), [0, 1, 2])
        self.assertEqual(f.rev(nodes[0]), 0)
        self.assertEqual(f.rev(nodes[1]), 1)
        self.assertEqual(f.rev(nodes[2]), 2)
        self.assertEqual(f.node(0), nodes[0])
        self.assertEqual(f.node(1), nodes[1])
        self.assertEqual(f.node(2), nodes[2])

def makeifileindextests(makefilefn, maketransactionfn):
    """Create a unittest.TestCase class suitable for testing file storage.

    ``makefilefn`` is a callable which receives the test case as an
    argument and returns an object implementing the ``ifilestorage`` interface.

    ``maketransactionfn`` is a callable which receives the test case as an
    argument and returns a transaction object.

    Returns a type that is a ``unittest.TestCase`` that can be used for
    testing the object implementing the file storage interface. Simply
    assign the returned value to a module-level attribute and a test loader
    should find and run it automatically.
    """
    d = {
        r'_makefilefn': makefilefn,
        r'_maketransactionfn': maketransactionfn,
    }
    return type(r'ifileindextests', (ifileindextests,), d)

def makeifiledatatests(makefilefn, maketransactionfn):
    d = {
        r'_makefilefn': makefilefn,
        r'_maketransactionfn': maketransactionfn,
    }
    return type(r'ifiledatatests', (ifiledatatests,), d)

def makeifilemutationtests(makefilefn, maketransactionfn):
    d = {
        r'_makefilefn': makefilefn,
        r'_maketransactionfn': maketransactionfn,
    }
    return type(r'ifilemutationtests', (ifilemutationtests,), d)