Incomplete Testbench

dv/ahb/SimpleDecoder/SimpleDecoder_tb.cpp

@@ -1,4 +1,36 @@
 #include <catch2/catch_test_macros.hpp>
 #include <VSimpleDecoder_tl.h>
 
-TEST_CASE("SimpleDecoder, Dummy Test") {}
+
+TEST_CASE("SimpleDecoder, Basic Functionality") {
+    VSimpleDecoder_tl* decoder = new VSimpleDecoder_tl;
+    Verilated::traceEverOn(true);
+    decoder->clk = 0;
+    decoder->nReset = 1;
+    decoder->eval();
+    decoder->clk = 1;
+    decoder->eval();
+    decoder->clk = 0;
+    decoder->eval();
+    decoder->nReset = 0;
+    decoder->eval();
+    decoder->clk = 1;
+    decoder->eval();
+
+    //test for addresses 1 to 20
+    for (int address = 1; address <= 3; ++address) {
+        int expected_sel = 1 << (address - 1);
+
+        decoder->addr = address;
+        decoder->eval();
+        decoder->clk = 0; //falling edge
+        decoder->eval();
+        decoder->clk = 1; //rising edge
+        decoder->eval();
+
+        CAPTURE(address, expected_sel); //capture the values
+        REQUIRE(decoder->sel == expected_sel);
+    }
+    decoder->final();
+    delete decoder;
+}