environs: turn environment configuration into a concrete type

cmd/juju/main_test.go

 package main
 
 import (
         "flag"
         "fmt"
         "io/ioutil"
         . "launchpad.net/gocheck"
         _ "launchpad.net/juju-core/environs/dummy"
         "launchpad.net/juju-core/testing"
         "os"
@@ skipping 71 matching lines @@
         c.Assert(lines[0], Equals, "usage: juju [options] <command> ...")
         assertError(c, lines, "error: flag provided but not defined: --environment")
 }
 
 var brokenConfig = `
 environments:
     one:
         type: dummy
         zookeeper: false
         broken: true
+        authorized-keys: i-am-a-key
 `
 
 // Induce failure to load environments and hence break Run.
 func breakJuju(c *C) (string, func()) {
         home := os.Getenv("HOME")
         path := c.MkDir()
         os.Setenv("HOME", path)
 
         jujuDir := filepath.Join(path, ".juju")
         err := os.Mkdir(jujuDir, 0777)
@@ skipping 57 matching lines @@
                 f := strings.Fields(lines[0])
                 if len(f) == 0 {
                         continue
                 }
                 c.Assert(f, Not(HasLen), 0)
                 names = append(names, f[0])
         }
         sort.Strings(names)
         c.Assert(names, DeepEquals, commandNames)
 }