Move code to use SSH "backends"

Default to shelling out to SSH when available.

Signed-off-by: Nathan LeClaire <nathan.leclaire@gmail.com>

test/integration/ssh-backends.bats

@@ -0,0 +1,45 @@
+#!/usr/bin/env bats
+
+load helpers
+
+export DRIVER=virtualbox
+export NAME="bats-$DRIVER-test"
+export MACHINE_STORAGE_PATH=/tmp/machine-bats-test-$DRIVER
+
+# Basic smoke test for SSH backends
+
+@test "$DRIVER: create SSH test box" {
+  run machine create -d $DRIVER $NAME
+  [[ "$status" -eq 0  ]]
+}
+
+@test "$DRIVER: test external ssh backend" {
+  run machine ssh $NAME -- df -h
+  [[ "$status" -eq 0 ]]
+}
+
+@test "$DRIVER: test command did what it purported to -- external ssh" {
+  run machine ssh $NAME echo foo
+  [[ "$output" == "foo"  ]]
+}
+
+@test "$DRIVER: test native ssh backend" {
+  run machine --native-ssh ssh $NAME -- df -h
+  [[ "$status" -eq 0  ]]
+}
+
+@test "$DRIVER: test command did what it purported to -- native ssh" {
+  run machine --native-ssh ssh $NAME echo foo
+  [[ "$output" == "foo"  ]]
+}
+
+@test "$DRIVER: remove machine after ssh backend test" {
+  run machine rm -f $NAME
+}
+
+# Cleanup of machine store should always be the last 'test'
+@test "$DRIVER: cleanup" {
+  run rm -rf $MACHINE_STORAGE_PATH
+  [ "$status" -eq 0  ]
+}
+