[Tests] add `nvm exec --lts` tests.

test/slow/nvm exec/Running "nvm exec --lts" should work

@@ -0,0 +1,18 @@
+#!/bin/sh
+
+set -ex
+
+die () { echo $@ ; exit 1; }
+
+. ../../../nvm.sh
+
+nvm install --lts || die 'nvm install --lts failed'
+
+NPM_VERSION_LTS="$(npm --version)"
+TEST_STRING="foo bar"
+
+nvm use 1.0.0 && [ "$(node --version)" = "v1.0.0" ] || die "\`nvm use\` failed!"
+
+[ "$(nvm exec --lts npm --version | tail -1)" = "$NPM_VERSION_LTS" ] || die "`nvm exec` failed to run with the correct version"
+
+[ "$(nvm exec --lts bash -c "printf '$TEST_STRING'" | tail -1)" = "$TEST_STRING" ] || die "\`nvm exec\` failed to run with a command including whitespace"

test/slow/nvm exec/setup_dir

@@ -3,6 +3,7 @@
 . ../../../nvm.sh
 nvm install 0.10.7
 nvm install 1.0.0
+nvm install --lts
 
 if [ -f ".nvmrc" ]; then
   mv .nvmrc .nvmrc.bak

test/slow/nvm exec/teardown_dir

@@ -4,6 +4,7 @@
 nvm deactivate
 nvm uninstall v0.10.7
 nvm uninstall v1.0.0
+nvm uninstall --lts
 
 rm .nvmrc