@Test
    void require_that_null_default_is_not_allowed() {
        assertThrows(IllegalArgumentException.class, () -> {
            new DefLine("s string default=null");
        });
    }
Tests parsing of a single line of a .def file

@author bratseth
@author gjoranv
configgen/src/test/java/com/yahoo/config/codegen/DefLineParsingTest.java