From d4eeebcea2adfade381fb0307a0bb4f7bd8ccc0f Mon Sep 17 00:00:00 2001
From: Darragh Bailey <dbailey@hp.com>
Date: Mon, 15 Dec 2014 16:32:22 +0000
Subject: [PATCH] Refactor code used to build tree into helpers

Split code up to simplify understanding and make use of helpers. fix
minor bug in retreival of parent commits to pass to the read-tree call.

Change-Id: Ie36520162a73cd621a61889f7860753dd911be54
---
 git_upstream/tests/base.py | 77 +++++++++++++++++++++++---------------
 1 file changed, 46 insertions(+), 31 deletions(-)

diff --git a/git_upstream/tests/base.py b/git_upstream/tests/base.py
index 35b8c3c..76f3c5d 100644
--- a/git_upstream/tests/base.py
+++ b/git_upstream/tests/base.py
@@ -54,6 +54,18 @@ nostrud exerci tation ullamcorper suscipit lobortis nisl ut aliquip ex ea
 commodo consequat."""
 
 
+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
+
+
 class DiveDir(fixtures.Fixture):
     """Dive into given directory and return back on cleanup.
 
@@ -144,9 +156,39 @@ class BaseTestCase(testtools.TestCase):
         self.useFixture(DiveDir(repo_path))
         self.repo = self.testrepo.repo
         self.git = self.repo.git
+        self._graph = {}
 
         self.addOnException(self.attach_graph_info)
 
+    def _commit(self, node):
+        p_node = get_node_to_pick(node)
+        if p_node:
+            self.git.cherry_pick(self._graph[p_node])
+        else:
+            # standard commit
+            self.testrepo.add_commits(1, ref="HEAD")
+
+    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([True for p in parents if p.startswith("=")]):
+            # special merge commit using inverse of 'ours' by
+            # emptying the current index and then reading in any
+            # trees of the nodes prefixed with '='
+            self.git.merge(*commits, s="ours", no_commit=True)
+            use = [str(self._graph[p.lstrip("=")])
+                   for p in parents if p.startswith("=")]
+            self.git.read_tree(empty=True)
+            self.git.read_tree(*use, u=True, reset=True)
+            self.git.commit(m="Merging %s into %s" %
+                            (",".join(parent_nodes[1:]),
+                                parent_nodes[0]))
+            self.git.clean(f=True, d=True, x=True)
+        else:
+            # standard merge
+            self.git.merge(*commits, no_edit=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
@@ -187,8 +229,6 @@ class BaseTestCase(testtools.TestCase):
             [('A', []), ('C', ['B']), ('B', ['A'])]
         """
 
-        self._graph = {}
-
         # first commit is special, assume root commit and repo has 1 commit
         node, parents = graph_def[0]
         if not parents:
@@ -200,6 +240,7 @@ class BaseTestCase(testtools.TestCase):
         for node, parents in graph_def[1:]:
             # other root commits
             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)
@@ -210,38 +251,12 @@ class BaseTestCase(testtools.TestCase):
 
             else:
                 # checkout the dependent node
-                self.git.checkout(self._graph[parents[0]])
-
+                self.git.checkout(self._graph[parents[0].lstrip('=')])
                 if len(parents) > 1:
                     # merge commits
-                    parent_nodes = [p.strip("=") for p in parents]
-                    commits = [str(self._graph[p]) for p in parent_nodes[1:]]
-                    if any([True for p in parents if p.startswith("=")]):
-                        # special merge commit using inverse of 'ours'
-                        self.git.merge(*commits, s="ours", no_commit=True)
-                        use = str(self._graph[
-                            next(p.strip("=") for p in parents
-                                 if p.startswith("="))])
-                        self.git.read_tree(use, u=True, reset=True)
-                        self.git.commit(m="Merging %s into %s" %
-                                        (",".join(parent_nodes), node))
-                    else:
-                        # standard merge
-                        self.git.merge(*commits, no_edit=True)
+                    self._merge_commit(node, parents)
                 else:
-                    m = re.search(r'(.*)(\d+)$', node)
-                    if m:
-                        # cherry-pick 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)
-                        to_pick = self._graph[node_name]
-                        self.git.cherry_pick(to_pick)
-                    else:
-                        # standard commit
-                        self.testrepo.add_commits(1, ref="HEAD")
-
+                    self._commit(node)
             self._graph[node] = self.repo.commit()
 
         for name, node in branches: