Refactor code structure for improved readability and maintainability

test/errors.test.js

@@ -0,0 +1,27 @@
+import test from "node:test";
+import assert from "node:assert/strict";
+import { apiError, describe, sourceError } from "../server/errors.js";
+
+test("Ошибки API: код и статус для клиентов", () => {
+  assert.deepEqual(describe(apiError(404, "group_not_found", "В документе нет группы 1-А.")), {
+    status: 404,
+    code: "group_not_found",
+    message: "В документе нет группы 1-А.",
+  });
+  assert.deepEqual(describe({ code: "LIMIT_FILE_SIZE" }).code, "file_too_large");
+  // Faults of the server itself never show their technical text.
+  const internal = describe(new TypeError("Cannot read properties of undefined"));
+  assert.equal(internal.status, 500);
+  assert.equal(internal.code, "internal");
+  assert.doesNotMatch(internal.message, /undefined/);
+});
+
+test("Ошибки источника: таймаут curl отдельно от недоступности", () => {
+  assert.equal(sourceError({ code: 28 }).code, "source_timeout");
+  assert.equal(sourceError({ code: 28 }).status, 504);
+  assert.equal(sourceError({ killed: true, signal: "SIGTERM" }).code, "source_timeout");
+  assert.equal(sourceError({ code: 6 }).code, "source_unavailable");
+  assert.equal(sourceError({ code: 22 }).status, 502);
+  const own = apiError(502, "source_invalid", "Таблица недель не распознана.");
+  assert.equal(sourceError(own), own);
+});