Add test script

scripts/test

@@ -0,0 +1,20 @@
+#!/bin/bash
+tempfile=".test_output.tmp"
+
+if [[ -n $1 ]]; then
+	nvim --headless --noplugin -u specs/init.vim -c "PlenaryBustedFile $1" | tee "${tempfile}"
+else
+	nvim --headless --noplugin -u specs/init.vim -c "PlenaryBustedDirectory specs/ {minimal_init = 'specs/init.vim'}" | tee "${tempfile}"
+fi
+
+# Plenary doesn't emit exit code 1 when tests have errors during setup
+errors=$(sed 's/\x1b\[[0-9;]*m//g' "${tempfile}" | awk '/(Errors|Failed) :/ {print $3}' | grep -v '0')
+
+rm "${tempfile}"
+
+if [[ -n $errors ]]; then
+  echo "Tests failed"
+  exit 1
+fi
+
+exit 0