assertSuccess(parser("0"))
        assertSuccess(parser("5"))
        assertSuccess(parser("13"))
        assertSuccess(parser("1_000_000"))

        // unsigned integers
        assertSuccess(parser("0u"))
        assertSuccess(parser("5U"))
        assertSuccess(parser("13u"))
        assertSuccess(parser("1_000_000U"))

        // long integers
        assertSuccess(parser("0L"))
        assertSuccess(parser("5l"))

000003e0  88 1e 30 85 b4 c0 46 c9  5c 85 ef 17 03 03 00 8b  |..0...F.\.......|
000003f0  a6 13 6e 2a 9f 36 5e 06  de 8a f8 95 68 0a 05 2b  |..n*.6^.....h..+|
00000400  e7 e7 fa 1b 2c 69 0c 30  75 a1 81 5a e6 e6 ab c5  |....,i.0u..Z....|
00000410  22 b0 7d e1 ba 4f d7 75  89 88 23 35 be 36 9d 64  |".}..O.u..#5.6.d|
00000420  3e 16 8d 5f 42 0f 6f 9a  78 8f 45 df 21 3e 4b 34  |>.._B.o.x.E.!>K4|