diff --git a/tb/tb_mux4_1.v b/tb/tb_mux4_1.v
new file mode 100644
index 0000000..078dd32
--- /dev/null
+++ b/tb/tb_mux4_1.v
@@ -0,0 +1,53 @@
+`timescale 1ns / 1ps
+`include "tb_tools.vh"
+
+module tb_mux4_1 ();
+
+    reg  [1:0]  sel;
+    reg  [31:0] in_1;
+    reg  [31:0] in_2;
+    reg  [31:0] in_3;
+    reg  [31:0] in_4;
+    wire [31:0] out;
+
+    mux4_1 mux (
+        .in_1(in_1),
+        .in_2(in_2),
+        .in_3(in_3),
+        .in_4(in_4),
+        .sel(sel),
+        .out(out)
+    );
+
+    initial begin
+        in_1 = 1'b0;
+        in_2 = 1'b0;
+        in_3 = 1'b0;
+        in_4 = 1'b0;
+        sel = 2'b00;
+        `assert("mux in_1: 0, in_2: 0, in_3: 0, in_4: 0, sel: 0", out, 0)
+        in_1 = 1'b1;
+        `assert("mux in_1: 1, in_2: 0, in_3: 0, in_4: 0, sel: 0", out, 1)
+        sel = 2'b01;
+        `assert("mux in_1: 1, in_2: 0, in_3: 0, in_4: 0, sel: 1", out, 0)
+        in_2 = 1'b1;
+        `assert("mux in_1: 1, in_2: 1, in_3: 0, in_4: 0, sel: 1", out, 1)
+        sel = 2'b10;
+        `assert("mux in_1: 1, in_2: 0, in_3: 0, in_4: 0, sel: 2", out, 0)
+        in_3 = 1'b1;
+        `assert("mux in_1: 1, in_2: 1, in_3: 1, in_4: 0, sel: 2", out, 1)
+        sel = 2'b11;
+        `assert("mux in_1: 1, in_2: 0, in_3: 1, in_4: 0, sel: 3", out, 0)
+        in_4 = 1'b1;
+        `assert("mux in_1: 1, in_2: 1, in_3: 1, in_4: 1, sel: 3", out, 1)
+        in_1 = 1'b0;
+        `assert("mux in_1: 0, in_2: 1, in_3: 1, in_4: 1, sel: 1", out, 1)
+        in_2 = 1'b0;
+        `assert("mux in_1: 0, in_2: 0, in_3: 1, in_4: 1, sel: 1", out, 1)
+        sel = 2'b00;
+        `assert("mux in_1: 0, in_2: 0, in_3: 1, in_4: 1, sel: 0", out, 0)
+
+        `end_message
+    end
+
+endmodule : tb_mux4_1
diff --git a/tb/tb_registers_bank.v b/tb/tb_registers_bank.v
new file mode 100644
index 0000000..599b27b
--- /dev/null
+++ b/tb/tb_registers_bank.v
@@ -0,0 +1,75 @@
+`timescale 1ns / 1ps
+`include "tb_tools.vh"
+
+module tb_registers_bank ();
+    reg         clk;
+    reg         reset;
+    integer     i;
+    reg         we;
+    reg  [4:0]  sel_in;
+    reg  [4:0]  sel_out_a;
+    reg  [4:0]  sel_out_b;
+    reg  [31:0] data_in;
+    wire [31:0] data_out_a;
+    wire [31:0] data_out_b;
+
+    registers_bank registers_bank (
+        .clock(clk),
+        .reset(reset),
+        .we(we),
+        .sel_in(sel_in),
+        .sel_out_a(sel_out_a),
+        .sel_out_b(sel_out_b),
+        .data_in(data_in),
+        .data_out_a(data_out_a),
+        .data_out_b(data_out_b)
+    );
+
+    initial begin
+        reset = 1'b1;
+        #10
+        reset = 1'b0;
+    end
+
+    initial begin
+        clk = 1'b0;
+        for (i = 0; i < 100; i = i + 1) begin
+            #1 clk = ~clk;
+        end
+    end
+
+    initial begin
+
+        we = 1'b0;
+        sel_in = 5'b00000;
+        sel_out_a = 5'b00000;
+        sel_out_b = 5'b00000;
+        data_in = 32'b0;
+        `assert("registers_bank we: 0, sel_in: 0, sel_out_a: 0, sel_out_b: 0, data_in: 0", data_out_a, 0)
+        we = 1'b1;
+        data_in = 32'b1;
+        `assert("registers_bank we: 1, sel_in: 0, sel_out_a: 0, sel_out_b: 0, data_in: 1", data_out_a, 0)
+        sel_in = 5'b00001;
+        `assert("registers_bank we: 1, sel_in: 1, sel_out_a: 0, sel_out_b: 0, data_in: 1", data_out_a, 0)
+        sel_out_a = 5'b00001;
+        `assert("registers_bank we: 1, sel_in: 1, sel_out_a: 1, sel_out_b: 0, data_in: 1", data_out_a, 1)
+        `assert("registers_bank we: 1, sel_in: 1, sel_out_a: 1, sel_out_b: 0, data_in: 1", data_out_b, 0)
+        sel_out_b = 5'b00001;
+        `assert("registers_bank we: 1, sel_in: 1, sel_out_a: 1, sel_out_b: 1, data_in: 1", data_out_b, 1)
+        we = 1'b0;
+        data_in = 32'b11;
+        `assert("registers_bank we: 0, sel_in: 1, sel_out_a: 1, sel_out_b: 1, data_in: 3", data_out_a, 1)
+        `assert("registers_bank we: 0, sel_in: 1, sel_out_a: 1, sel_out_b: 1, data_in: 3", data_out_b, 1)
+        data_in = 32'b111;
+        sel_in = 5'b11111;
+        sel_out_a = 5'b11111;
+        we = 1'b1;
+        `assert("registers_bank we: 1, sel_in: 31, sel_out_a: 31, sel_out_b: 1, data_in: 7", data_out_a, 7)
+        `assert("registers_bank we: 1, sel_in: 31, sel_out_a: 31, sel_out_b: 1, data_in: 7", data_out_b, 1)
+
+        `end_message
+    end
+
+
+
+endmodule : tb_registers_bank
diff --git a/tb/tb_tools.vh b/tb/tb_tools.vh
index d8774c8..ad0875c 100644
--- a/tb/tb_tools.vh
+++ b/tb/tb_tools.vh
@@ -1,5 +1,5 @@
 `define assert(message, expected, got) \
-    #20 \
+    #4 \
     if(expected !== got) begin \
         $display("\033[0;31m[FAILED]\033[0m : %s - got: %d, expected: %d", message, expected, got); \
     end