Fix running tests by directory (zidhuss#27)

lua/neotest-minitest/init.lua

@@ -108,14 +108,33 @@ function NeotestAdapter.build_spec(args)
   end
 
   local function run_dir()
-    table.insert(script_args, position.path .. "/**/*_test.rb")
+    local tree = args.tree
+    local root = tree:root():data().path
+
+    -- This emulates an combination of Rake::TestTask with loader=:direct and
+    -- rake_test_loader
+    table.insert(script_args, "-e")
+    table.insert(script_args, "while (f = ARGV.shift) != '--'; require f; end")
+
+    -- Instruct Ruby to stop parsing options
+    table.insert(script_args, "--")
+
+    for _, node in tree:iter_nodes() do
+      if node:data().type == "file" then
+        local path = node:data().path
+	table.insert(script_args, path)
+      end
+    end
+
+    -- Mark the end of test files
+    table.insert(script_args, "--")
   end
 
   if position.type == "file" then run_by_filename() end
 
   if position.type == "test" or position.type == "namespace" then run_by_name() end
 
-  if position.type == "dir" then return run_dir() end
+  if position.type == "dir" then run_dir() end
 
   local command = vim.tbl_flatten({
     config.get_test_cmd(),