functests: Add some tests

test/helpers.lua

@@ -225,6 +225,14 @@ local function which(exe)
   end
 end
 
+local function shallowcopy(orig)
+  local copy = {}
+  for orig_key, orig_value in pairs(orig) do
+    copy[orig_key] = orig_value
+  end
+  return copy
+end
+
 return {
   eq = eq,
   neq = neq,
@@ -238,4 +246,5 @@ return {
   check_cores = check_cores,
   hasenv = hasenv,
   which = which,
+  shallowcopy = shallowcopy,
 }