Adjusted test.py to use an installed vcs by default.

Protects agaist the off chance that the user doesn't have Arch (tla)
installed ;).

Changed Arch.name from "Arch" to "arch" so that each VCSs .name
matches the module name.  This allows us to use vcs.VCS_ORDER (a list
of module names) to set up the allowed values of BugDir.vcs_name.

3 files changed, 19 insertions, 8 deletions

diff --git a/libbe/arch.py b/libbe/arch.py
index 4687555..48129b5 100644
--- a/libbe/arch.py
+++ b/libbe/arch.py
@@ -45,7 +45,7 @@ def new():
     return Arch()
 
 class Arch(vcs.VCS):
-    name = "Arch"
+    name = "arch"
     client = client
     versioned = True
     _archive_name = None
diff --git a/libbe/bugdir.py b/libbe/bugdir.py
index 5b942d3..675b744 100644
--- a/libbe/bugdir.py
+++ b/libbe/bugdir.py
@@ -213,7 +213,7 @@ that the Arch VCS backend *enforces* ids with this format.""",
 settings easy.  Don't set this attribute.  Set .vcs instead, and
 .vcs_name will be automatically adjusted.""",
                          default="None",
-                         allowed=["None", "Arch", "bzr", "darcs", "git", "hg"])
+                         allowed=["None"]+vcs.VCS_ORDER)
     def vcs_name(): return {}
 
     def _get_vcs(self, vcs_name=None):
diff --git a/libbe/vcs.py b/libbe/vcs.py
index be28846..b1fd114 100644
--- a/libbe/vcs.py
+++ b/libbe/vcs.py
@@ -38,16 +38,23 @@ import doctest
 
 from utility import Dir, search_parent_directories
 from subproc import CommandError, invoke
+from plugin import get_plugin
 
+# List VCS modules in order of preference.
+# Don't list this module, it is implicitly last.
+VCS_ORDER = ['arch', 'bzr', 'darcs', 'git', 'hg']
+
+def set_preferred_vcs(name):
+    global VCS_ORDER
+    assert name in VCS_ORDER, \
+        'unrecognized VCS %s not in\n  %s' % (name, VCS_ORDER)
+    VCS_ORDER.remove(name)
+    VCS_ORDER.insert(0, name)
 
 def _get_matching_vcs(matchfn):
     """Return the first module for which matchfn(VCS_instance) is true"""
-    import arch
-    import bzr
-    import darcs
-    import git
-    import hg
-    for module in [arch, bzr, darcs, git, hg]:
+    for submodname in VCS_ORDER:
+        module = get_plugin('libbe', submodname)
         vcs = module.new()
         if matchfn(vcs) == True:
             return vcs
@@ -117,6 +124,10 @@ class VCS(object):
         self._duplicateDirname = None
         self.encoding = encoding
         self.version = self._get_version()
+    def __str__(self):
+        return "<%s %s>" % (self.__class__.__name__, id(self))
+    def __repr__(self):
+        return str(self)
     def _vcs_version(self):
         """
         Return the VCS version string.