@Test
public void testConvertFromFieldsMissingScheme() throws Exception {

    thrown.expect(HttpException.class);
    thrown.expectMessage("Mandatory request header ':scheme' not found");
    final List<Header> headers = Arrays.<Header>asList(
            new BasicHeader(":method", "GET"),
            new BasicHeader(":authority", "www.example.com"),
            new BasicHeader(":path", "/"),
            new BasicHeader("custom", "value"));
    final DefaultH2RequestConverter converter = new DefaultH2RequestConverter();
    converter.convert(headers);
}