@Test
    void underscore_in_package_is_allowed() throws IOException, DefParser.DefParserException {
        StringBuilder sb = createDefTemplate();
        String line = "package=a_b.c\n";
        sb.append(line);
        createParser(sb.toString()).parse();

        sb = createDefTemplate();
        line = "package=a_b.c_d\n";
        sb.append(line);
        createParser(sb.toString()).parse();
    }
Tests setting explicit java package in the def file.

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