tests: add simple loopback module

axi/tb/axi_cocotb_loopback_test/axi4_loopback.sv

@@ -0,0 +1,17 @@
+`timescale 1ns/1ps
+
+module axi4_loopback #(
+  parameter int unsigned ADDR_W = 32,
+  parameter int unsigned DATA_W = 64,
+  parameter int unsigned ID_W   = 4,
+  parameter int unsigned USER_W = 1
+)(
+  axi4_if.slave  s_axi,
+  axi4_if.master m_axi
+);
+
+  // compact loopback/pasthrough to test ifaces
+  assign m_axi.req  = s_axi.req;
+  assign s_axi.resp = m_axi.resp;
+
+endmodule