testClient.documentCountError = true;
        final long count = testClient.getDocumentCount("nonexistent_index");
        assertEquals(-1L, count);
    }

    @Test
    public void test_getAliasCount_returnsZeroOnError() {
        // The real getAliasCount returns 0 on error; our test double tracks this
        testClient.aliasCountError = true;
        final int count = testClient.getAliasCount("nonexistent_index");