@Test
    void uppercase_chars_are_not_allowed() {
        assertThrows(CodegenRuntimeException.class, () -> {
            createParser("package=Foo.bar\n").getTree();
        });
    }
Tests setting explicit java package in the def file.

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