add symlink test case

spec/02-integration/02-cmd/02-start_stop_spec.lua

@@ -1036,6 +1036,46 @@ describe("kong start/stop #" .. strategy, function()
     end)
   end)
 
+  describe("runtime_prefix", function()
+    it("is created on demand by `kong prepare`", function()
+      local dir, cleanup = helpers.make_temp_dir()
+      finally(cleanup)
+
+      local cmd = fmt("prepare -p %q", dir)
+      assert.truthy(kong_exec(cmd), "expected '" .. cmd .. "' to succeed")
+      assert.truthy(helpers.path.isdir(dir .. "/runtime"),
+                    "expected '" .. dir .. "/runtime' directory to be created")
+    end)
+
+    it("can be a user-created symlink", function()
+      local prefix, cleanup = helpers.make_temp_dir()
+      finally(cleanup)
+
+      local runtime_prefix
+      runtime_prefix, cleanup = helpers.make_temp_dir()
+      finally(cleanup)
+
+      assert.truthy(helpers.execute(fmt("ln -sf %q %q/runtime", runtime_prefix, prefix)),
+                    "failed to symlink runtime prefix")
+
+      local preserve_prefix = true
+      assert(helpers.start_kong({
+        prefix = prefix,
+        database = "off",
+        nginx_conf = "spec/fixtures/custom_nginx.template",
+      }, nil, preserve_prefix))
+
+      finally(function()
+        helpers.stop_kong(prefix)
+      end)
+
+      wait_until_healthy(prefix)
+
+      assert.truthy(helpers.path.exists(runtime_prefix .. "/worker_events.sock"),
+                    "worker events socket was not created in the runtime_prefix dir")
+    end)
+  end)
+
   describe("dangling socket cleanup", function()
     local pidfile = TEST_CONF.nginx_pid