Switch to using fixtures-git for testing

Use library to handle setup of fixtures for testing with git.

Change-Id: I5b39f8d52beca848adb20d646c26d91c4b977b92

git_upstream/tests/base.py

@@ -17,83 +17,15 @@ import io
 import logging
 import os
 from pprint import pformat
-import re
 import subprocess
-import tempfile
 
-import faker
 import fixtures
-import git
+import fixtures_git
 import testtools
 from testtools.content import text_content
 import yaml
 
 
-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)
-
-
 def get_scenarios(scenarios_path):
     """Returns a list of scenarios, each scenario being describe
     by it's name, and a dict containing the parameters
@@ -131,218 +63,6 @@ class DiveDir(fixtures.Fixture):
         os.chdir(self.path)
 
 
-class GitRepo(fixtures.Fixture):
-    """Create an empty git repo in which to operate."""
-
-    def __init__(self, path=None):
-        self.path = path
-        self._faker = faker.Faker()
-
-    def _setUp(self):
-        self._file_list = set()
-        if not self.path:
-            tempdir = self.useFixture(fixtures.TempDir())
-            self.path = os.path.join(tempdir.path, 'git')
-
-        os.mkdir(self.path)
-        g = git.Git(self.path)
-        g.init()
-
-        self.repo = git.Repo(self.path)
-        self.repo.git.config('user.email', 'user@example.com')
-        self.repo.git.config('user.name', 'Example User')
-        self._create_file_commit()
-
-    def _create_file(self, contents=None):
-        if not contents:
-            contents = "\n\n".join(self._faker.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
-            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(ids[x], message_prefix=message_prefix)
-
-
-class BuildTree(object):
-
-    def __init__(self, gitrepo, tree, branches):
-        self.graph = {}
-        self.gitrepo = gitrepo
-        self.repo = gitrepo.repo
-        self.git = self.gitrepo.repo.git
-        self._build_git_tree(tree, branches)
-
-    def _commit(self, node):
-        p_node = _get_node_to_pick(node)
-        if p_node:
-            self.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.git.merge(*commits, s="ours", no_commit=True)
-            except git.exc.GitCommandError as exc:
-                if 'refusing to merge unrelated histories' in exc.stderr:
-                    self.git.merge(*commits, s="ours", no_commit=True,
-                                   allow_unrelated_histories=True)
-                else:
-                    raise
-            self.git.read_tree(empty=True)
-            self.git.read_tree(*use, u=True, reset=True)
-        elif len(commits) < 2:
-            # standard merge
-            try:
-                self.git.merge(*commits, no_commit=True)
-            except git.exc.GitCommandError as exc:
-                if 'refusing to merge unrelated histories' in exc.stderr:
-                    self.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.git.merge(*commits, s="ours", no_commit=True)
-            except git.exc.GitCommandError as exc:
-                if 'refusing to merge unrelated histories' in exc.stderr:
-                    self.git.merge(*commits, s="ours", no_commit=True,
-                                   allow_unrelated_histories=True)
-                else:
-                    raise
-            self.git.read_tree(empty=True)
-            self.git.read_tree("HEAD", *commits)
-            self.git.checkout("--", ".")
-        self.git.commit(m="[%s] Merging %s into %s" %
-                        (node, ",".join(parent_nodes[1:]),
-                            parent_nodes[0]))
-        self.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.git.symbolic_ref("HEAD", "refs/heads/%s" % node)
-                self.git.rm(".", r=True, cached=True)
-                self.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.git.checkout(self.repo.commit())
-                self.git.branch(node, D=True)
-
-            else:
-                # checkout the dependent node
-                self.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.git.branch(name, str(self.graph[node]), f=True)
-
-        # return to master
-        self.git.checkout("master")
-
-    def _commits_from_nodes(self, nodes=[]):
-
-        return [self.graph[n] for n in nodes]
-
-
 class BaseTestCase(testtools.TestCase):
     """Base Test Case for all tests."""
 
@@ -352,14 +72,6 @@ class BaseTestCase(testtools.TestCase):
         super(BaseTestCase, self).setUp()
 
         self.logger = self.useFixture(fixtures.FakeLogger(level=logging.DEBUG))
-        self.testrepo = self.useFixture(GitRepo())
-        repo_path = self.testrepo.path
-        self.useFixture(DiveDir(repo_path))
-
-        self.repo = self.testrepo.repo
-        self.git = self.repo.git
-
-        self.addOnException(self.attach_graph_info)
 
         # _testMethodDoc is a hidden attribute containing the docstring for
         # the given test, useful for some tests where description is not
@@ -367,10 +79,25 @@ class BaseTestCase(testtools.TestCase):
         if getattr(self, '_testMethodDoc', None):
             self.addDetail('description', text_content(self._testMethodDoc))
 
-        self.gittree = None
         if hasattr(self, 'tree'):
-            self.gittree = BuildTree(
+            self.testrepo = self.useFixture(
-                self.testrepo, self.tree, self.branches.values())
+                fixtures_git.GitFixture(
+                    graph=self.tree,
+                    branches=self.branches.values(),
+                )
+            )
+        else:
+            self.testrepo = self.useFixture(
+                fixtures_git.GitFixture())
+
+        self.gittree = self.testrepo.gittree
+
+        self.useFixture(DiveDir(self.testrepo.path))
+
+        self.repo = self.testrepo.repo
+        self.git = self.repo.git
+
+        self.addOnException(self.attach_repo_info)
 
         if hasattr(self, 'pre_script'):
             self.run_pre_script()
@@ -426,16 +153,17 @@ class BaseTestCase(testtools.TestCase):
         self.addDetail('post-script-output',
                        text_content(output.decode('utf-8')))
 
-    def attach_graph_info(self, exc_info):
+    def attach_repo_info(self, exc_info):
         # appears to be an odd bug where this method is called twice
         # if registered with addOnException so make sure to guard
         # that the path actually exists before running
-        if not (hasattr(self.testrepo, 'path') and
+        if not os.path.exists(self.testrepo.path):
-                os.path.exists(self.testrepo.path)):
             return
 
+        # in case we haven't setup yet
         if not self.gittree or not self.gittree.graph:
             return
+
         self.addDetail('graph-dict', text_content(pformat(self.gittree.graph)))
 
         self.addDetail(

git_upstream/tests/build-test-tree.py

@@ -42,8 +42,8 @@ def build_test_tree(basedir, filename):
         with base.DiveDir(testrepo.path):
 
             if 'tree' in data:
-                base.BuildTree(testrepo, data['tree'],
+                base.fixtures_git.gitfixture.GitTree(
-                               data['branches'].values())
+                    testrepo, data['tree'], data['branches'].values())
 
             if 'pre-script' in data:
                 output = subprocess.check_output(data['pre-script'],

git_upstream/tests/searchers/test_searchers.py

@@ -53,7 +53,7 @@ class TestUpstreamMergeBaseSearcher(TestWithScenarios, BaseTestCase):
                                              patterns=pattern, repo=self.repo)
 
         self.assertEqual(
-            self.gittree._commits_from_nodes(reversed(self.expected_changes)),
+            self.gittree.commits_from_nodes(reversed(self.expected_changes)),
             searcher.list(self.branches['upstream'][0]))
 
         self.assertThat(self.logger.output,

git_upstream/tests/strategies/test_strategies.py

@@ -55,7 +55,7 @@ class TestStrategies(TestWithScenarios, BaseTestCase):
             search_refs=[self.branches['upstream'][0]])
 
         self.assertEqual(
-            self.gittree._commits_from_nodes(self.expected_changes),
+            self.gittree.commits_from_nodes(self.expected_changes),
             [c for c in strategy.filtered_iter()])
 
         self.assertThat(self.logger.output,

git_upstream/tests/test_commands.py

@@ -94,7 +94,8 @@ class TestLoggingOptions(base.BaseTestCase):
             'upstream': ('upstream/master', 'E'),
         }
 
-        self.gittree = base.BuildTree(self.testrepo, tree, branches.values())
+        self.gittree = base.fixtures_git.gitfixture.GitTree(
+            self.testrepo, tree, branches.values())
 
         cmdline = self.parser.get_default('script_cmdline')
 

git_upstream/tests/test_import.py

@@ -57,7 +57,8 @@ class TestImport(base.BaseTestCase):
             'import': ('import', 'C1')
         }
 
-        self.gittree = base.BuildTree(self.testrepo, tree, branches.values())
+        self.gittree = base.fixtures_git.gitfixture.GitTree(
+            self.testrepo, tree, branches.values())
         iu = ImportUpstream("master", "upstream/master", "import")
         iu.finish()
         self.assertEqual("", self.git.status(porcelain=True),
@@ -94,7 +95,8 @@ class TestImport(base.BaseTestCase):
             'import': ('import', 'C1')
         }
 
-        self.gittree = base.BuildTree(self.testrepo, tree, branches.values())
+        self.gittree = base.fixtures_git.gitfixture.GitTree(
+            self.testrepo, tree, branches.values())
         iu = ImportUpstream("master", "upstream/master", "import")
         # create a dummy file
         open('dummy-file', 'a').close()
@@ -127,7 +129,8 @@ class TestImport(base.BaseTestCase):
             'upstream': ('upstream/master', 'E'),
         }
 
-        self.gittree = base.BuildTree(self.testrepo, tree, branches.values())
+        self.gittree = base.fixtures_git.gitfixture.GitTree(
+            self.testrepo, tree, branches.values())
         self.git.tag("tag-um-1", "upstream/master")
         self.git.tag("tag-um-2", "upstream/master")
         iu = ImportUpstream("master", "tag-um-1", "import/{describe}")

test-requirements.txt

@@ -1,5 +1,5 @@
 hacking>=0.11.0,<0.12  # Apache-2.0
-faker>=0.8.16
+fixtures-git>=0.1.0  # Apache-2.0
 mock>=2.0.0
 sphinx>=1.5.1,!=1.6.6,!=1.6.7,<2.0.0;python_version=='2.7'  # BSD
 sphinx>=1.5.1,!=1.6.6,!=1.6.7,!=2.1.0;python_version>='3.4'  # BSD