test: make docx/odt exporter tests network-independent

The docx and odt exporter tests export a testDocument containing image
blocks pointing at a remote placeholder URL (placehold.co), which the
default exporter file resolver fetches over the network. This made the
tests flaky and caused 'TypeError: fetch failed' (ETIMEDOUT/ENETUNREACH)
in sandboxed CI without outbound network access.

Add a test-only resolveFileUrl that returns an in-memory 332x322 JPEG
(matching the remote image dimensions so existing snapshots are
preserved) for the placeholder URL, and wire it into the docx and odt
exporter tests.

Author: nperez0111

packages/xl-docx-exporter/src/docx/__snapshots__/withCustomOptions/document.xml.rels

@@ -13,6 +13,6 @@
     <Relationship Id="FAKE-ID" Type="http://schemas.openxmlformats.org/officeDocument/2006/relationships/hyperlink" Target="https://interactive-examples.mdn.mozilla.net/media/cc0-audio/t-rex-roar.mp3" TargetMode="External"/>
     <Relationship Id="FAKE-ID" Type="http://schemas.openxmlformats.org/officeDocument/2006/relationships/hyperlink" Target="" TargetMode="External"/>
     <Relationship Id="FAKE-ID" Type="http://schemas.openxmlformats.org/officeDocument/2006/relationships/hyperlink" Target="https://www.blocknotejs.org" TargetMode="External"/>
-    <Relationship Id="FAKE-ID" Type="http://schemas.openxmlformats.org/officeDocument/2006/relationships/image" Target="media/c0c1a1a0abe0fdd4533c468319977db996162c95.gif"/>
+    <Relationship Id="FAKE-ID" Type="http://schemas.openxmlformats.org/officeDocument/2006/relationships/image" Target="media/50e4c971936c813eeeacc22f2ae97b4bc2a023f0.gif"/>
     <Relationship Id="FAKE-ID" Type="http://schemas.openxmlformats.org/officeDocument/2006/relationships/fontTable" Target="fontTable.xml"/>
 </Relationships>

packages/xl-docx-exporter/src/docx/docxExporter.test.ts

@@ -18,6 +18,7 @@ import { docxDefaultSchemaMappings } from "./defaultSchema/index.js";
 import { DOCXExporter } from "./docxExporter.js";
 import { ColumnBlock, ColumnListBlock } from "@blocknote/xl-multi-column";
 import { partialBlocksToBlocksForTesting } from "@shared/formatConversionTestUtil.js";
+import { testResolveFileUrl } from "@shared/util/testFileResolver.js";
 
 const getZIPEntryContent = (entries: Entry[], fileName: string) => {
   const entry = entries.find((entry) => {
@@ -40,6 +41,7 @@ describe("exporter", () => {
         },
       }),
       docxDefaultSchemaMappings,
+      { resolveFileUrl: testResolveFileUrl },
     );
     const doc = await exporter.toDocxJsDocument(testDocument, {
       sectionOptions: {},
@@ -73,6 +75,7 @@ describe("exporter", () => {
           },
         }),
         docxDefaultSchemaMappings,
+        { resolveFileUrl: testResolveFileUrl },
       );
 
       const doc = await exporter.toDocxJsDocument(testDocument, {
@@ -145,7 +148,9 @@ describe("exporter", () => {
           columnList: ColumnListBlock,
         },
       });
-      const exporter = new DOCXExporter(schema, docxDefaultSchemaMappings);
+      const exporter = new DOCXExporter(schema, docxDefaultSchemaMappings, {
+        resolveFileUrl: testResolveFileUrl,
+      });
       const doc = await exporter.toDocxJsDocument(
         partialBlocksToBlocksForTesting(schema, [
           {
@@ -227,6 +232,7 @@ describe("exporter", () => {
         },
       }),
       docxDefaultSchemaMappings,
+      { resolveFileUrl: testResolveFileUrl },
     );
     const doc = await exporter.toDocxJsDocument(testDocument, {
       sectionOptions: {},

packages/xl-odt-exporter/src/odt/odtExporter.test.ts

@@ -11,6 +11,7 @@ import { odtDefaultSchemaMappings } from "./defaultSchema/index.js";
 import { ODTExporter } from "./odtExporter.js";
 import { ColumnBlock, ColumnListBlock } from "@blocknote/xl-multi-column";
 import { partialBlocksToBlocksForTesting } from "@shared/formatConversionTestUtil.js";
+import { testResolveFileUrl } from "@shared/util/testFileResolver.js";
 
 beforeAll(async () => {
   // @ts-expect-error - Blob polyfill for Node test environment
@@ -27,6 +28,7 @@ describe("exporter", () => {
         },
       }),
       odtDefaultSchemaMappings,
+      { resolveFileUrl: testResolveFileUrl },
     );
     const odt = await exporter.toODTDocument(testDocument);
     await testODTDocumentAgainstSnapshot(odt, {
@@ -47,6 +49,7 @@ describe("exporter", () => {
           },
         }),
         odtDefaultSchemaMappings,
+        { resolveFileUrl: testResolveFileUrl },
       );
 
       const odt = await exporter.toODTDocument(testDocument, {
@@ -76,7 +79,9 @@ describe("exporter", () => {
           columnList: ColumnListBlock,
         },
       });
-      const exporter = new ODTExporter(schema, odtDefaultSchemaMappings);
+      const exporter = new ODTExporter(schema, odtDefaultSchemaMappings, {
+        resolveFileUrl: testResolveFileUrl,
+      });
       const odt = await exporter.toODTDocument(
         partialBlocksToBlocksForTesting(schema, [
           {

shared/util/testFileResolver.ts

@@ -0,0 +1,54 @@
+/**
+ * Test-only file resolver for exporter tests.
+ *
+ * The `testDocument` used across exporter tests contains image blocks that
+ * point at a remote placeholder URL (https://placehold.co/332x322.jpg). The
+ * default exporter file resolver fetches these over the network (via a CORS
+ * proxy), which makes the tests flaky and causes failures in sandboxed CI
+ * environments without outbound network access (`TypeError: fetch failed`).
+ *
+ * To keep the tests deterministic and network-independent, this module returns
+ * a tiny in-memory JPEG with the exact same dimensions as the remote image
+ * (332x322). Preserving the dimensions is important: the exported snapshots
+ * embed the image size (e.g. `cx="3162300" cy="3067050"` = 332x322 * 9525
+ * EMU/px), so any substitute must report identical dimensions to avoid
+ * breaking existing snapshots.
+ */
+
+// A minimal valid baseline JPEG whose SOF0 marker declares a 332x322 image.
+// Only the header is meaningful (image-meta reads dimensions from SOF0); the
+// pixel data is intentionally empty as exporters never decode the contents.
+const PLACEHOLDER_332x322_JPEG_BASE64 =
+  "/9j/4AAQSkZJRgABAQAAAQABAAD/2wBDABAQEBAQEBAQEBAQEBAQEBAQEBAQEBAQEBAQEBAQEBAQEBAQEBAQEBAQEBAQEBAQEBAQEBAQEBAQEBAQEBAQEBD/wAALCAFCAUwBAREA/9oACAEBAAA/AP/Z";
+
+function base64ToArrayBuffer(base64: string): ArrayBuffer {
+  if (typeof atob === "function") {
+    const binary = atob(base64);
+    const bytes = new Uint8Array(binary.length);
+    for (let i = 0; i < binary.length; i++) {
+      bytes[i] = binary.charCodeAt(i);
+    }
+    return bytes.buffer;
+  }
+  // Node.js fallback
+  const buf = Buffer.from(base64, "base64");
+  return buf.buffer.slice(buf.byteOffset, buf.byteOffset + buf.byteLength);
+}
+
+/**
+ * A {@link ExporterOptions.resolveFileUrl} implementation for tests that avoids
+ * any network access. It returns a local 332x322 JPEG blob for the placeholder
+ * image URL used in `testDocument`, and falls back to fetching for any other
+ * URL.
+ */
+export async function testResolveFileUrl(url: string): Promise<string | Blob> {
+  if (url.includes("placehold.co")) {
+    return new Blob([base64ToArrayBuffer(PLACEHOLDER_332x322_JPEG_BASE64)], {
+      type: "image/jpeg",
+    });
+  }
+
+  // For any non-image/unknown URL, return it unchanged so the caller can fetch
+  // it. In practice exporter tests only resolve the placeholder image above.
+  return url;
+}