/****
* playback_controller_tb.sv - a testbench for the playback_controller.sv
*                             module.
*                             
* @author: Dilanthi Prentice
* @date: [unsure of due date]
*
* */
`ifdef VERILATOR
    `include "sdvd_defs.sv"
`endif
import sdvd_defs::SPEED;

module playback_controller_tb; 
    logic clk, reset;
    logic play, ff;
    SPEED speed;
    int errors;

    //instatiate the dut
    playback_controller dut(clk, reset, play, ff, speed);

    //clock generation
    initial clk = 0;
    always #5 clk = ~clk;

    //play button press
    task press_play();
        play = 1;
        @(posedge clk);
        play = 0;
        @(posedge clk);
    endtask

    //ff button press
    task press_ff();
        ff = 1;
        @(posedge clk);
        ff = 0;
        @(posedge clk);
    endtask

    initial
    begin
        @(posedge clk);
        play = 0;
        ff = 0;
        
        reset = 1;
        @(posedge clk);
        reset = 0;
        
        @(posedge clk);
        assert (speed === 0) else
            begin    
            $error("Speed not zero after reset");
            errors++;
            end
       @(posedge clk);
        
        press_play();
        assert (speed === 1) else
            begin
            $error("Play not working");
            errors++;
            end

        press_play();
        assert (speed === 0) else
            begin
            $error("Pause not working");
            errors++;
            end

        press_ff();
        assert (speed === 2) else
            begin
            $error("Not in FF2 after ff btn pressed once");
            errors++;
            end

        press_ff();
        assert (speed === 4) else
            begin
            $error("Not in FF4 after ff btn pressed twice");
            errors++;
            end
        
        press_ff();
        assert (speed === 8) else
            begin
            $error("Not in FF8 after ff btn pressed thrice");
            errors++;
            end

        press_play();
        assert (speed === 0) else
            begin
            $error("Unsuccessful return to pause after play btn pressed from a FF state");
            errors++;
            end

        if (errors === 0)
            $display("No errors detected in playback_controller");
        
        $finish;
    end
endmodule