Initial fixture for git library

Provide fixture object that can be used to build isolated test envs
when working with git and developing git tooling that uses the git
application.

Change-Id: I5b39f8d52beca848adb20d646c26d91c4b977b92
This commit is contained in:
Darragh Bailey 2018-03-10 11:17:45 +00:00 committed by Darragh Bailey
parent 4b3c30652b
commit 453b3c0b71
9 changed files with 447 additions and 2 deletions

3
.stestr.conf Normal file
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[DEFAULT]
test_path=tests
top_dir=./

344
fixtures_git/__init__.py Normal file
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# Copyright (c) 2013-2016 Hewlett-Packard Enterprise Development Company, L.P.
#
# Licensed under the Apache License, Version 2.0 (the "License"); you may
# not use this file except in compliance with the License. You may obtain
# a copy of the License at
#
# http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
# WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
# License for the specific language governing permissions and limitations
# under the License.
import os
import re
import shutil
import tempfile
import fixtures
import git
import loremipsum
__all__ = [
'GitFixture'
]
def _get_node_to_pick(node):
m = re.search(r'(.*)(\d+)$', node)
if m:
# get copy of a another change
node_number = int(m.group(2)) - 1
node_name = m.group(1)
if node_number > 0:
node_name += str(node_number)
return node_name
return None
_NOT_VISITED = 0
_VISITED = 1
_FINISHED = 2
def reverse_toposort(data):
# convert to dict for linear lookup times when returning
data = dict(data)
# keep track of nodes visited and processed
# by checking if a child has been visited before but not processed you
# can detect a back edge and abort since the graph is not acyclic
visited = dict()
# DFS algorithm with customization to handle use of '=' notation for merge
# commits and also the additional dependency for cherry-picking
nodes_to_visit = []
for i in data.keys():
if i not in visited:
nodes_to_visit.append(i)
while nodes_to_visit:
node = nodes_to_visit.pop()
if visited.get(node) is _VISITED:
# already visited so just return it with it's deps
yield (node, data[node])
visited[node] = _FINISHED
continue
elif visited.get(node) is _FINISHED:
continue
visited[node] = _VISITED
nodes_to_visit.append(node)
# special case for cherry-picking changes
c_node = _get_node_to_pick(node)
if c_node and c_node not in visited:
nodes_to_visit.append(c_node)
for d in data[node]:
r_d = d.strip('=')
if r_d not in visited:
nodes_to_visit.append(r_d)
else:
# if we've already visited a dep but not processed it,
# then we have a back edge of some kind
if visited[r_d] is _VISITED:
message = ("Graph is not acyclic: %s is a dependency "
"of %s, but has been visited without being "
"processed before it." % (r_d, node))
raise RuntimeError(message)
class GitTree(object):
def __init__(self, gitrepo, tree, branches):
self.graph = {}
self.gitrepo = gitrepo
self.repo = gitrepo.repo
self._build_git_tree(tree, branches)
def _commit(self, node):
p_node = _get_node_to_pick(node)
if p_node:
self.repo.git.cherry_pick(self.graph[p_node], x=True)
else:
# standard commit
self.gitrepo.add_commits(1, ref="HEAD",
message_prefix="[%s]" % node)
def _merge_commit(self, node, parents):
# merge commits
parent_nodes = [p.lstrip("=") for p in parents]
commits = [str(self.graph[p]) for p in parent_nodes[1:]]
if any([p.startswith("=") for p in parents]):
# special merge commit using inverse of 'ours' by
# emptying the current index and then reading in any
# trees of the nodes prefixed with '='
use = [str(self.graph[p.lstrip("=")])
for p in parents if p.startswith("=")]
try:
self.repo.git.merge(*commits, s="ours", no_commit=True)
except git.exc.GitCommandError as exc:
if 'refusing to merge unrelated histories' in exc.stderr:
self.repo.git.merge(*commits, s="ours", no_commit=True,
allow_unrelated_histories=True)
else:
raise
self.repo.git.read_tree(empty=True)
self.repo.git.read_tree(empty=True)
self.repo.git.read_tree(*use, u=True, reset=True)
elif len(commits) < 2:
# standard merge
try:
self.repo.git.merge(*commits, no_commit=True)
except git.exc.GitCommandError as exc:
if 'refusing to merge unrelated histories' in exc.stderr:
self.repo.git.merge(*commits, no_commit=True,
allow_unrelated_histories=True)
else:
raise
else:
# multi-branch merge, git is not great at handling
# merging multiple orphaned branches
try:
self.repo.git.merge(*commits, s="ours", no_commit=True)
except git.exc.GitCommandError as exc:
if 'refusing to merge unrelated histories' in exc.stderr:
self.repo.git.merge(*commits, s="ours", no_commit=True,
allow_unrelated_histories=True)
else:
raise
self.repo.git.read_tree(empty=True)
self.repo.git.read_tree("HEAD", *commits)
self.repo.git.checkout("--", ".")
self.repo.git.commit(m="[%s] Merging %s into %s" %
(node, ",".join(parent_nodes[1:]),
parent_nodes[0]))
self.repo.git.clean(f=True, d=True, x=True)
def _build_git_tree(self, graph_def, branches=[]):
"""Helper function to build a git repository from a graph definition
of nodes and their parent nodes. A list of branches may be provided
where each element has two members corresponding to the name and the
target node it references.
Supports unordered graphs, only requirement is that there is a commit
defined with no parents, which will become the root commit.
Root commits can specified by an empty list as the second member:
('NodeA', [])
Merge commits are specified by multiple nodes:
('NodeMerge', ['Node1', 'Node2'])
As the import subcommand to git-upstream supports a special merge
commit that ignores all previous history from the other tree being
merged in using the 'ours' strategy. You specify this by defining
a parent node as '=<Node>'. The resulting merge commit contains just
the contents of the tree from the specified parent while still
recording the parents.
Following will result in a merge commit 'C', with parents 'P1' and
'P2', but will have the same tree as 'P1'.
('C', ['=P1', 'P2'])
The tree building code can handle a graph definition being out of
order but will fail to find certain circular dependencies and may
result in an infinite loop.
Examples:
[('A', []), ('B', ['A']), ('C', ['B'])]
[('A', []), ('C', ['B']), ('B', ['A'])]
"""
# require that graphs must have at least 1 node with no
# parents, which is a root commit in git
if not any([True for _, parents in graph_def if not parents]):
assert("No root commit defined in test graph")
for node, parents in reverse_toposort(graph_def):
if not parents:
# root commit
self.repo.git.symbolic_ref("HEAD", "refs/heads/%s" % node)
self.repo.git.rm(".", r=True, cached=True,
with_exceptions=False)
self.repo.git.clean(f=True, d=True, x=True)
self.gitrepo.add_commits(1, ref="HEAD",
message_prefix="[%s]" % node)
# only explicitly listed branches should exist afterwards
self.repo.git.checkout(self.repo.commit())
self.repo.git.branch(node, D=True)
else:
# checkout the dependent node
self.repo.git.checkout(self.graph[parents[0].lstrip('=')])
if len(parents) > 1:
# merge commits
self._merge_commit(node, parents)
else:
self._commit(node)
self.graph[node] = self.repo.commit()
for name, node in branches:
self.repo.git.branch(name, str(self.graph[node]), f=True)
# return to master
self.repo.git.checkout("master")
def commits_from_nodes(self, nodes=[]):
return [self.graph[n] for n in nodes]
class GitFixture(fixtures.Fixture):
"""Create a git repo in which to operate.
By default creates an empty git repository under a temporary
directory and deletes it after use.
It accepts options to automatically define a git repository
layout based on list of commits setting the given branches to
the relevant node once built.
:ivar graph: Iterable describing the tree of git commits to create.
:ivar branches: Dict of node to branch names to set once finished.
:ivar path: Custom path to use, otherwise will create a temporary
directory to use and set the 'path' attribute to it.
:ivar user: Dict describing a user to use for commits, defaults
to 'Example User <user@example.com>',
:ivar clean_on_exit: Control whether to delete the tempoary path
once complete, defaults to 'True', but is ignored if 'path'
is provided.
"""
def __init__(self, graph=None, branches=None, path=None, user=None,
clean_on_exit=True):
# set attributes for use
self.path = path
self.gittree = None
self.repo = None
# internal attributes
self._graph = graph or []
self._branches = branches or []
self._user = {
'name': 'Example User',
'email': 'user@example.com',
}
self._user.update(user or {})
self._clean_on_exit = clean_on_exit
def _setUp(self):
self._file_list = set()
if not self.path:
tempdir = self.useFixture(fixtures.TempDir())
self.path = os.path.join(tempdir.path, 'git')
if self._clean_on_exit is True:
self.addCleanup(shutil.rmtree, tempdir.path)
os.mkdir(self.path)
g = git.Git(self.path)
g.init()
self.repo = git.Repo(self.path)
self.repo.git.config('user.email', self._user['email'])
self.repo.git.config('user.name', self._user['name'])
self.repo.git.commit(m="Initialize empty repo", allow_empty=True)
if self._graph:
self.gittree = GitTree(self, self._graph, self._branches)
def _create_file(self):
contents = "\n\n".join(loremipsum.get_paragraphs(3))
# always want to ensure the files added to the repo are unique no
# matter which branch they are added to, as otherwise there may
# be conflicts caused by replaying local changes and performing
# merges
while True:
tmpfile = tempfile.NamedTemporaryFile(
dir=self.repo.working_dir, delete=False)
if tmpfile.name not in self._file_list:
self._file_list.add(tmpfile.name)
break
# case where same filename in use on a different branch
tmpfile.close()
os.remove(tmpfile.name)
tmpfile.write(contents.encode('utf-8'))
tmpfile.close()
return tmpfile.name
def _create_file_commit(self, change_id=None, message_prefix=None):
filename = self._create_file()
self.repo.git.add(filename)
message = "Adding %s" % os.path.basename(filename)
if message_prefix:
message = "%s %s" % (message_prefix, message)
if change_id:
message = message + "\n\nChange-Id: %s" % change_id
self.repo.git.commit(m=message)
def add_commits(self, num=1, ref="HEAD", change_ids=[],
message_prefix=None):
"""Create the given number of commits using generated files"""
if ref != "HEAD":
self.repo.git.checkout(ref)
num = max(num, len(change_ids))
ids = list(change_ids) + [None] * (num - len(change_ids))
for x in range(num):
self._create_file_commit(
change_id=ids[x], message_prefix=message_prefix)

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requirements.txt Normal file
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fixtures
GitPython
loremipsum

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flake8
hacking
sphinx
stestr
testtools

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tests/__init__.py Normal file
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tests/simple/__init__.py Normal file
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# Copyright (c) 2014 Hewlett-Packard Development Company, L.P.
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
# http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or
# implied.
# See the License for the specific language governing permissions and
# limitations under the License.
#
import testtools
import fixtures_git
class TestBuildTree(testtools.TestCase):
def test_basic(self):
pass
def test_merge(self):
pass
def test_merge_and_replace(self):
pass
def test_merge_unrelated_history(self):
pass

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tests/test_toposort.py Normal file
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# Copyright (c) 2014 Hewlett-Packard Development Company, L.P.
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
# http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or
# implied.
# See the License for the specific language governing permissions and
# limitations under the License.
#
import testtools
import fixtures_git
class TestResolve(testtools.TestCase):
def test_ordered(self):
pass
def test_unordered(self):
pass
def test_merge(self):
pass
def test_multiple_merges(self):
pass
def test_merge_unrelated_history(self):
pass

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tox.ini
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@ -6,10 +6,25 @@ skip_missing_interpreters = True
[testenv]
usedevelop = True
setenv =
LANG=en_US.UTF-8
PYTHONDONTWRITEBYTECODE=1
SUBUNIT_FORMATTER=tee testr_subunit_log
VIRTUAL_ENV={envdir}
install_command = pip install -U {opts} {packages}
deps = -r{toxinidir}/test-requirements.txt
deps = -r{toxinidir}/requirements.txt
-r{toxinidir}/test-requirements.txt
commands =
python setup.py test
stestr run --slowest {posargs}
[testenv:pep8]
commands = flake8
[testenv:cover]
commands =
python setup.py stestr --coverage --coverage-package-name=fixtures_git
coverage report
[testenv:docs]
commands =
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[testenv:venv]
commands = {posargs}
[flake8]
ignore=H236,H40
show-source = True
exclude = .venv,.tox,dist,doc,build,*.egg