fix: Resolve TypeScript errors

Signed-off-by: Hermes Agent <hermes@nosuchhost>

client/node_modules/abstract-leveldown/test/leveldown-test.js

@@ -0,0 +1,12 @@
+module.exports = function (test, testCommon) {
+  test('setUp common', testCommon.setUp)
+
+  test('test database open method exists', function (t) {
+    var db = testCommon.factory()
+    t.ok(db, 'database object returned')
+    t.ok(typeof db.open === 'function', 'open() function exists')
+    t.end()
+  })
+
+  test('tearDown', testCommon.tearDown)
+}