rust/pv*: Unit test flag parsing

Add a unit test for flag parsing.

In order to ease this test, add derive Eq to ControlFlags and
Msb0Flags64. For the same test, add derive Default to
CreateBootImageArgs and the structs used in it. The latter can be
limited to only derive when testing to avoid confusion with any
user-level default.

Acked-by: Steffen Eiden <seiden@linux.ibm.com>
Reviewed-by: Marc Hartmayer <mhartmay@linux.ibm.com>
Signed-off-by: Jakob Naucke <naucke@linux.ibm.com>
Signed-off-by: Jan Höppner <hoeppner@linux.ibm.com>

rust/pv_core/src/utils.rs

@@ -34,7 +34,7 @@ pub trait Flags<T>: From<T> + for<'a> From<&'a T> {
 ///
 /// Wraps an u64 to set/get individual bits
 #[repr(C)]
-#[derive(Debug, Clone, Copy, Default, AsBytes, FromZeroes, FromBytes)]
+#[derive(Debug, Clone, Copy, Default, AsBytes, FromZeroes, FromBytes, Eq, PartialEq)]
 pub struct Msb0Flags64(U64<BigEndian>);
 impl Flags<u64> for Msb0Flags64 {
     #[track_caller]