adding test fixtures so that we can run tests 'offline'

test/offlineFixtures.js

@@ -0,0 +1,99 @@
+/*
+ * Copyright (c) 2026 by Christian Kellner.
+ * Licensed under Apache-2.0 with Commons Clause and Attribution/Naming Clause
+ */
+
+import { readFile } from 'fs/promises';
+import path from 'path';
+import { fileURLToPath } from 'url';
+
+const __dirname = path.dirname(fileURLToPath(import.meta.url));
+const FIXTURES_DIR = path.join(__dirname, 'testFixtures');
+
+const testProviderConfig = JSON.parse(
+  await readFile(new URL('./provider/testProvider.json', import.meta.url), 'utf-8'),
+);
+
+// hostname → providerName, built from testProvider.json
+const hostnameToProvider = {};
+// providerName → list page pathname (for distinguishing list vs detail URLs)
+const providerListPath = {};
+
+for (const [name, cfg] of Object.entries(testProviderConfig)) {
+  if (!cfg.url) continue;
+  try {
+    const parsed = new URL(cfg.url);
+    hostnameToProvider[parsed.hostname] = name;
+    providerListPath[name] = parsed.pathname;
+  } catch {
+    // skip malformed URLs
+  }
+}
+
+async function tryReadFile(filepath) {
+  try {
+    return await readFile(filepath, 'utf-8');
+  } catch {
+    return null;
+  }
+}
+
+/**
+ * Returns fixture HTML for the given URL by mapping hostname → provider name,
+ * then distinguishing list vs detail pages by comparing the URL path against
+ * the configured list URL path from testProvider.json.
+ */
+export async function readFixture(url) {
+  let hostname, pathname;
+  try {
+    const parsed = new URL(url);
+    hostname = parsed.hostname;
+    pathname = parsed.pathname;
+  } catch {
+    return null;
+  }
+
+  const providerName = hostnameToProvider[hostname];
+  if (!providerName) return null;
+
+  if (providerListPath[providerName] === pathname) {
+    return tryReadFile(path.join(FIXTURES_DIR, `${providerName}.html`));
+  }
+
+  // Detail page: prefer dedicated detail fixture, fall back to list fixture
+  const detailHtml = await tryReadFile(path.join(FIXTURES_DIR, `${providerName}_detail.html`));
+  if (detailHtml) return detailHtml;
+  return tryReadFile(path.join(FIXTURES_DIR, `${providerName}.html`));
+}
+
+/**
+ * Returns a fetch replacement that intercepts immoscout mobile API calls and
+ * serves pre-downloaded JSON fixtures. Throws for any other URL to prevent
+ * accidental live network traffic in offline mode.
+ */
+export function buildFetchMock() {
+  let listData = null;
+  let detailData = null;
+
+  return async (url) => {
+    const urlStr = String(url);
+
+    if (urlStr.includes('api.mobile.immobilienscout24.de/search/list')) {
+      if (!listData) {
+        const raw = await tryReadFile(path.join(FIXTURES_DIR, 'immoscout_list.json'));
+        listData = raw ? JSON.parse(raw) : { resultListItems: [] };
+      }
+      return { ok: true, status: 200, json: () => Promise.resolve(listData) };
+    }
+
+    if (urlStr.includes('api.mobile.immobilienscout24.de/expose/')) {
+      if (!detailData) {
+        const raw = await tryReadFile(path.join(FIXTURES_DIR, 'immoscout_detail.json'));
+        detailData = raw ? JSON.parse(raw) : { sections: [], contact: {} };
+      }
+      return { ok: true, status: 200, json: () => Promise.resolve(detailData) };
+    }
+
+    throw new Error(`Network request blocked in offline mode: ${urlStr}`);
+  };
+}