SSH gives error message if `ssh` binary is not found. [closes GH-161]

CHANGELOG.md

@@ -1,5 +1,6 @@
 ## 0.6.4 (unreleased)
 
+  - SSH gives error message if `ssh` binary is not found. [GH-161]
   - SSH gives proper error message if VM is not running. [GH-167]
   - Fix some issues with undefined constants in command errors.
 

lib/vagrant/errors.rb

@@ -243,6 +243,11 @@ module Vagrant
       error_key(:ssh_key_bad_permissions)
     end
 
+    class SSHUnavailable < VagrantError
+      status_code(45)
+      error_key(:ssh_unavailable)
+    end
+
     class SSHUnavailableWindows < VagrantError
       status_code(10)
       error_key(:ssh_unavailable_windows)

lib/vagrant/ssh.rb

@@ -26,6 +26,8 @@ module Vagrant
                                                 :ssh_port => port(opts))
       end
 
+      raise Errors::SSHUnavailable.new if !Kernel.system("which ssh > /dev/null 2>&1")
+
       options = {}
       options[:port] = port(opts)
       [:host, :username, :private_key_path].each do |param|

templates/locales/en.yml

@@ -43,6 +43,7 @@ en:
         permissions on the following file to 0600 and then try running this command again:
 
         %{key_path}
+      ssh_unavailable: "`ssh` binary could not be found. Is an SSH client installed?"
       ssh_unavailable_windows: |-
         `vagrant ssh` isn't available on the Windows platform. The
         vagrant.ppk file for use with Putty is available at:

test/vagrant/ssh_test.rb

@@ -22,10 +22,23 @@ class SshTest < Test::Unit::TestCase
       mock_ssh
       @ssh.stubs(:check_key_permissions)
       Kernel.stubs(:exec)
+      Kernel.stubs(:system).returns(true)
 
       Vagrant::Util::Platform.stubs(:leopard?).returns(false)
     end
 
+    should "raise an exception if SSH is not found" do
+      Kernel.stubs(:system).returns(false)
+      Kernel.expects(:system).returns(false).with() do |command|
+        assert command =~ /^which ssh/
+        true
+      end
+
+      assert_raises(Vagrant::Errors::SSHUnavailable) {
+        @ssh.connect
+      }
+    end
+
     should "check key permissions prior to exec" do
       exec_seq = sequence("exec_seq")
       @ssh.expects(:check_key_permissions).with(@env.config.ssh.private_key_path).once.in_sequence(exec_seq)