diff --git a/src/tests/backend/specs/ExportEtherpad.js b/src/tests/backend/specs/ExportEtherpad.js
new file mode 100644
index 000000000..8a4c056cc
--- /dev/null
+++ b/src/tests/backend/specs/ExportEtherpad.js
@@ -0,0 +1,53 @@
+'use strict';
+
+const assert = require('assert').strict;
+const common = require('../common');
+const exportEtherpad = require('../../../node/utils/ExportEtherpad');
+const padManager = require('../../../node/db/PadManager');
+const plugins = require('../../../static/js/pluginfw/plugin_defs');
+const readOnlyManager = require('../../../node/db/ReadOnlyManager');
+
+describe(__filename, function () {
+  let padId;
+
+  beforeEach(async function () {
+    padId = common.randomString();
+    assert(!await padManager.doesPadExist(padId));
+  });
+
+  describe('exportEtherpadAdditionalContent', function () {
+    let hookBackup;
+
+    before(async function () {
+      hookBackup = plugins.hooks.exportEtherpadAdditionalContent || [];
+      plugins.hooks.exportEtherpadAdditionalContent = [{hook_fn: () => ['custom']}];
+    });
+
+    after(async function () {
+      plugins.hooks.exportEtherpadAdditionalContent = hookBackup;
+    });
+
+    it('exports custom records', async function () {
+      const pad = await padManager.getPad(padId);
+      await pad.db.set(`custom:${padId}`, 'a');
+      const data = await exportEtherpad.getPadRaw(pad.id, null);
+      assert.equal(data[`custom:${padId}`], 'a');
+    });
+
+    it('export from read-only pad uses read-only ID', async function () {
+      const pad = await padManager.getPad(padId);
+      const readOnlyId = await readOnlyManager.getReadOnlyId(padId);
+      await pad.db.set(`custom:${padId}`, 'a');
+      const data = await exportEtherpad.getPadRaw(padId, readOnlyId);
+      assert.equal(data[`custom:${readOnlyId}`], 'a');
+      assert(!(`custom:${padId}` in data));
+    });
+
+    it('does not export records from pad with similar ID', async function () {
+      const pad = await padManager.getPad(padId);
+      await pad.db.set(`custom:${padId}x`, 'a');
+      const data = await exportEtherpad.getPadRaw(pad.id, null);
+      assert(!(`custom:${padId}x` in data));
+    });
+  });
+});
diff --git a/src/tests/backend/specs/ImportEtherpad.js b/src/tests/backend/specs/ImportEtherpad.js
index 6dfd11112..3158c308d 100644
--- a/src/tests/backend/specs/ImportEtherpad.js
+++ b/src/tests/backend/specs/ImportEtherpad.js
@@ -5,6 +5,7 @@ const authorManager = require('../../../node/db/AuthorManager');
 const db = require('../../../node/db/DB');
 const importEtherpad = require('../../../node/utils/ImportEtherpad');
 const padManager = require('../../../node/db/PadManager');
+const plugins = require('../../../static/js/pluginfw/plugin_defs');
 const {randomString} = require('../../../static/js/pad_utils');
 
 describe(__filename, function () {
@@ -167,4 +168,41 @@ describe(__filename, function () {
       });
     }
   });
+
+  describe('exportEtherpadAdditionalContent', function () {
+    let hookBackup;
+
+    before(async function () {
+      hookBackup = plugins.hooks.exportEtherpadAdditionalContent || [];
+      plugins.hooks.exportEtherpadAdditionalContent = [{hook_fn: () => ['custom']}];
+    });
+
+    after(async function () {
+      plugins.hooks.exportEtherpadAdditionalContent = hookBackup;
+    });
+
+    it('imports from custom prefix', async function () {
+      await importEtherpad.setPadRaw(padId, JSON.stringify({
+        ...makeExport(makeAuthorId()),
+        'custom:testing': 'a',
+        'custom:testing:foo': 'b',
+      }));
+      const pad = await padManager.getPad(padId);
+      assert.equal(await pad.db.get(`custom:${padId}`), 'a');
+      assert.equal(await pad.db.get(`custom:${padId}:foo`), 'b');
+    });
+
+    it('rejects records for pad with similar ID', async function () {
+      await assert.rejects(importEtherpad.setPadRaw(padId, JSON.stringify({
+        ...makeExport(makeAuthorId()),
+        'custom:testingx': 'x',
+      })), /unexpected pad ID/);
+      assert(await db.get(`custom:${padId}x`) == null);
+      await assert.rejects(importEtherpad.setPadRaw(padId, JSON.stringify({
+        ...makeExport(makeAuthorId()),
+        'custom:testingx:foo': 'x',
+      })), /unexpected pad ID/);
+      assert(await db.get(`custom:${padId}x:foo`) == null);
+    });
+  });
 });