cmd: No longer panic if cwd is deleted

cmd/juju/synctools_test.go

 // Copyright 2013 Canonical Ltd.
 // Licensed under the AGPLv3, see LICENCE file for details.
 
 package main
 
 import (
         "errors"
         "time"
 
         "github.com/juju/loggo"
@@ skipping 107 matching lines @@
                 sctx: &sync.SyncContext{
                         MajorVersion: 1,
                         MinorVersion: 2,
                 },
         },
 }
 
 func (s *syncToolsSuite) TestSyncToolsCommand(c *gc.C) {
         for i, test := range syncToolsCommandTests {
                 c.Logf("test %d: %s", i, test.description)
-                targetEnv, err := environs.PrepareFromName("test-target", nullContext(), s.configStore)
+                targetEnv, err := environs.PrepareFromName("test-target", nullContext(c), s.configStore)
                 c.Assert(err, gc.IsNil)
                 called := false
                 syncTools = func(sctx *sync.SyncContext) error {
                         c.Assert(sctx.AllVersions, gc.Equals, test.sctx.AllVersions)
                         c.Assert(sctx.MajorVersion, gc.Equals, test.sctx.MajorVersion)
                         c.Assert(sctx.MinorVersion, gc.Equals, test.sctx.MinorVersion)
                         c.Assert(sctx.DryRun, gc.Equals, test.sctx.DryRun)
                         c.Assert(sctx.Dev, gc.Equals, test.sctx.Dev)
                         c.Assert(sctx.Public, gc.Equals, test.sctx.Public)
                         c.Assert(sctx.Source, gc.Equals, test.sctx.Source)
@@ skipping 54 matching lines @@
         }
         // Run sync-tools command with --destination flag.
         ctx, err := runSyncToolsCommand(c, "-e", "test-target", "--destination", dir)
         c.Assert(err, gc.IsNil)
         c.Assert(ctx, gc.NotNil)
         c.Assert(called, jc.IsTrue)
         // Check deprecated message was logged.
         c.Check(tw.Log, jc.LogMatches, messages)
         s.Reset(c)
 }