Add debouncer TB and fixup on debouncer

verification/debouncer_tb.sv

@@ -1,8 +1,63 @@
+`timescale 1ns / 1ps
 module debouncer_tb;
 
 logic clk,reset,source;
 wire out;
 
+int errors;
+
 debouncer Dut (.*);
 
+initial begin
+    clk = 0;
+    forever #10 clk = ~clk;
+end
+
+initial begin
+    $display("Testing debouncer");
+    reset = 1;
+    source = 0;
+    @(posedge clk);
+    @(posedge clk);
+    reset = 0;
+    @(posedge clk);
+    source = 1;
+    #1;
+    assert (out == 1) else begin
+        $error("Output not brought high during first press");
+        errors++;
+    end
+    @(posedge clk);
+    #1;
+    assert (out == 0) else begin
+        $error("Output not brought low after first press");
+        errors++;
+    end
+    @(posedge clk);
+    source = 0;
+    @(posedge clk);
+    source = 1;
+    #1;
+    assert (out == 1) else begin
+        $error("Output not brought high during second press");
+        errors++;
+    end
+    source = 0;
+    @(posedge clk);
+    #1;
+    assert (out == 0) else begin
+        $error("Output not brought low after second press");
+        errors++;
+    end
+
+    if (errors == 0)
+        $display("Found no errors while testing debouncer");
+
+    $finish;
+
+end
+
+
+
+
 endmodule