chore(tests): make DB helpers imported on demand

This makes helpers function available for env where no DB provided

spec/helpers.lua

@@ -18,7 +18,6 @@ local CONSTANTS = reload_module("spec.internal.constants")
 local conf = reload_module("spec.internal.conf")
 local shell = reload_module("spec.internal.shell")
 local misc = reload_module("spec.internal.misc")
-local DB = reload_module("spec.internal.db")
 local grpc = reload_module("spec.internal.grpc")
 local dns_mock = reload_module("spec.internal.dns")
 local asserts = reload_module("spec.internal.asserts") -- luacheck: ignore
@@ -29,6 +28,31 @@ local client = reload_module("spec.internal.client")
 local wait = reload_module("spec.internal.wait")
 
 
+local db_entries = {
+  blueprints = true,
+  get_db_utils = true,
+  get_cache = true,
+  bootstrap_database = true,
+  each_strategy = true,
+  all_strategies = true,
+  validate_plugin_config_schema = true,
+  get_plugins_list = true,
+}
+
+
+local lazy_db_load_mt = {
+  __index = function(self, key)
+    if db_entries[key] or key == "db" then
+      DB = reload_module("spec.internal.db")
+      self.db = DB
+      for k, _ in pairs(db_entries) do
+        self[k] = DB[k]
+      end
+
+      return rawget(self, key)
+    end
+  end,
+}
 ----------------
 -- Variables/constants
 -- @section exported-fields
@@ -75,19 +99,14 @@ local wait = reload_module("spec.internal.wait")
 -- Exposed
 ----------
 -- @export
-  return {
+  return setmetatable({
   -- Penlight
   dir = require("pl.dir"),
   path = require("pl.path"),
   file = require("pl.file"),
   utils = require("pl.utils"),
 
   -- Kong testing properties
-  db = DB.db,
-  blueprints = DB.blueprints,
-  get_db_utils = DB.get_db_utils,
-  get_cache = DB.get_cache,
-  bootstrap_database = DB.bootstrap_database,
   bin_path = CONSTANTS.BIN_PATH,
   test_conf = conf,
   test_conf_path = CONSTANTS.TEST_CONF_PATH,
@@ -175,9 +194,6 @@ local wait = reload_module("spec.internal.wait")
   clean_prefix = cmd.clean_prefix,
   clean_logfile = cmd.clean_logfile,
   wait_for_invalidation = wait.wait_for_invalidation,
-  each_strategy = DB.each_strategy,
-  all_strategies = DB.all_strategies,
-  validate_plugin_config_schema = DB.validate_plugin_config_schema,
   clustering_client = client.clustering_client,
   https_server = require("spec.fixtures.https_server"),
   stress_generator = require("spec.fixtures.stress_generator"),
@@ -218,12 +234,9 @@ local wait = reload_module("spec.internal.wait")
   -- send signal to all Nginx workers, not including the master
   signal_workers = cmd.signal_workers,
 
-  -- returns the plugins and version list that is used by Hybrid mode tests
-  get_plugins_list = DB.clone_plugins_list,
-
   get_available_port = wait.get_available_port,
 
   make_temp_dir = misc.make_temp_dir,
 
   build_go_plugins = cmd.build_go_plugins,
-}
+}, lazy_db_load_mt)

spec/internal/cmd.lua

@@ -21,7 +21,7 @@ local prefix_handler = require("kong.cmd.utils.prefix_handler")
 local CONSTANTS = require("spec.internal.constants")
 local conf = require("spec.internal.conf")
 local shell = require("spec.internal.shell")
-local DB = require("spec.internal.db")
+local DB
 local pid = require("spec.internal.pid")
 local dns_mock = require("spec.internal.dns")
 
@@ -263,6 +263,10 @@ end
 --
 -- assert(helpers.start_kong( {database = "postgres"}, nil, nil, fixtures))
 local function start_kong(env, tables, preserve_prefix, fixtures)
+  if not DB then
+    DB = require("spec.internal.db")
+  end
+
   if tables ~= nil and type(tables) ~= "table" then
     error("arg #2 must be a list of tables to truncate")
   end