diff --git a/permutations/testbenches/PI_1_unshuffle_tb.v b/permutations/testbenches/PI_1_unshuffle_tb.v
new file mode 100644
index 0000000..a79d241
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+++ b/permutations/testbenches/PI_1_unshuffle_tb.v
@@ -0,0 +1,53 @@
+//testbench for module PI_1_unshuffle
+/*
+here random 6 bit number is sent as input whose value is then compared with the output
+which is connected to that input according to the condition of Pi 1 unshuffle
+relation between a connected input_index and output_index is : input_index= (6*output_index)%35 
+for example: input[6]==output[(6*6)%35=1]
+NOTE: input[35]=output[35]
+*/
+module pi_1_unshuffle_tb;
+  reg [6-1 : 0] data_in [0 : 35];
+  reg [6-1 : 0] data_out [0 : 35];
+  reg [6-1 : 0] temp [0:35];
+  
+  PI_1_unshuffle#(6) test(  //parameter DATA_WIDTH is 6
+    .data_in(data_in),
+    .data_out(data_out));
+  
+    initial begin
+    // Dump waves
+    $dumpfile("dump.vcd");
+    $dumpvars(1, test);
+    
+      for(int i=0;i<36;i++)begin
+        data_in[i]=$random%(1<<6); //random 6-bit number is sent as input
+        temp[i]=data_in[i];        //random number is stored at index same as that of input
+      end
+      
+      #10;
+      //compare output at index 0
+      if(data_out[0]!=temp[0]) begin
+        $display("data_in[0] not unshuffled correctly");
+          #10 $finish;
+        end      
+       
+      //compare output from indices 1 to 34 (both included)
+      for(int i=1;i<35;i++)begin
+        if(data_out[i]!=temp[(6*i)%35]) begin                    //compare with index found according  
+          $display("data_in[%d] not unshuffled correctly",i);//to condition mentioned in the header
+          #10 $finish;
+        end
+      end
+      
+      //compare output at index 35
+      if(data_out[35]!=temp[35]) begin
+        $display("data_in[35] not unshuffled correctly");
+          #10 $finish;
+        end
+ 
+      
+        $display("All tests passed.");
+        #10 $finish;
+      end
+endmodule