tl build: project:find() now correctly returns the current dir

spec/cli/source_dir_spec.lua

@@ -33,7 +33,7 @@ describe("-s --source-dir argument", function()
       })
    end)
    it("should die when the given directory doesn't exist", function()
-      util.run_mock_project(function() end, {
+      util.run_mock_project(finally, {
          dir_name = "no_source_dir_test",
          dir_structure = {
             ["tlconfig.lua"] = [[return {source_dir="src"}]],

tl

@@ -630,6 +630,7 @@ function project:files(inc_patt_arr, exc_patt_arr) -- iterate over the files in
    return coroutine.wrap(iter), self.dir
 end
 function project:find(path) -- allow for indexing with paths project:find("foo/bar") -> project.dir.foo.bar
+   if path == "" then return self.dir end -- empty string is the current dir
    local current_dir = self.dir
    for dirname in str_split(path, path_separator) do
       current_dir = current_dir[dirname]