module testbench; reg clk; initial begin $dumpfile("testbench.vcd"); $dumpvars(0, testbench); #0 clk = 0; repeat (10000) begin #5 clk = 1; #5 clk = 0; end $display("OKAY"); end reg i = 0; reg out; wire b; always @(posedge clk) begin i = i + 1; end top uut (clk,i,b); always @(posedge clk) out <= $past(i,9); assert_dff b1_test(.clk(clk), .test(b), .pat(out)); endmodule