tests/NetworkSecurityConfigTest/res/xml/expired_pin.xml

<?xml version="1.0" encoding="utf-8"?>
<network-security-config>
  <domain-config>
    <domain>android.com</domain>
    <!-- Invalid pin that has expired -->
    <pin-set expiration="2015-01-01">
      <pin digest="SHA-256">aaaaaaaaaaa2Y49orFOOQKurWxmmSFZhBCoQYcRhJ3Y=</pin>
    </pin-set>
  </domain-config>
</network-security-config>