FAILED: force of bus[0], got 000z, expected 0001. FAILED: force of bus[3:2], got 000z, expected 1101. FAILED: assignment of bus[1], got 00zz, expected 11z1. FAILED: release of bus[0], got 000z, expected 110z. FAILED: force of bus[2:1], got 000z, expected 0x1z.