Update environment.sv

Author: RDSik

src/tb/environment.sv

@@ -16,12 +16,22 @@ class environment;
 
     task init();
         begin
+            clock();
             reset();
             read();
             write();
         end
     endtask
 
+    task clock();
+        begin
+            dut_if.clk_i = 0;
+            forever begin
+                #(CLK_PER/2) dut_if.clk_i = ~dut_if.clk_i;
+            end
+        end
+    endtask
+    
     task reset();
         begin
             dut_if.arstn_i = 0;