Hands-on SVUnit Tutorial

Time to learn the basics of unit testing with SVUnit!

Edit the code and run it here: Hands-on SVUnit Tutorial on EDA Playground

Here’s a simple set of unit tests for an interface called svunitOnSwitch. The purpose of the design is to offer a few utility functions as well as to operate an on/off output.

The API of the svunitOnSwitch is as follows:

output logic on;
function logic true();
function logic false();
function int return43();
turn_on();
turn_off();

The svunitOnSwitch is defined as:

interface svunitOnSwitch (
  output logic on
);
  initial on = 'hx;

  function logic true();
    // no implementation yet
  endfunction

  function logic false();
    // no implementation yet
  endfunction

  function int return43();
    // no implementation yet
  endfunction

  function void turn_on();
    // no implementation yet
  endfunction

  function void turn_off();
    // no implementation yet
  endfunction
endinterface

The SVTESTs below are the acceptance unit tests that verify the functionality of the svunitOnSwitch. If you run the tests on EDA Playground you’ll see all the tests fail because none of the svunitOnSwitch functionality is implemented. Your job is to build a complete svunitOnSwitch, one requirement at a time, by:

• examining the requirement defined in the unit test

  (HINT: a unit test is marked by the `SVTEST macro)
• implementng the corresponding code in the svunitOnSwitch

  (HINT: watch for the “no implementation yet” comment)

• running the test suite to make sure your implementation satisfies the unit test

When you’ve gone through all the tests and your entire test suite passes, you’re done! You’ve verified the svunitOnSwitch and learned the basics of SVUnit!

Ready… set… go!

Edit the code and run it here: Hands-on SVUnit Tutorial on EDA Playground

`include "svunit_defines.svh"
import svunit_pkg::*;

module svunitDemo_unit_test;
  `SVUNIT_TESTS_BEGIN

  //------------------------------
  // test: true_test
  //   the true() function should
  //   return 1
  //------------------------------
  `SVTEST(true_returns_1)
    `FAIL_UNLESS(uut.true() === 1);
  `SVTEST_END


  //------------------------------
  // test: false_test
  //   the false() function should
  //   return 0
  //------------------------------
  `SVTEST(false_returns_0)
    `FAIL_UNLESS(uut.false() === 0);
  `SVTEST_END


  //-----------------------------------
  // test: return43
  //   The function return43() returns
  //   a value. this test should fail
  //   if that doesn't happen.
  //-----------------------------------
  `SVTEST(return43)
    `FAIL_UNLESS(uut.return43() === 43);
  `SVTEST_END


  //---------------------------------
  // test: turn_on
  //   our uut has an output pin
  //   called 'on' that we can
  //   assert via turn_on()
  //---------------------------------
  `SVTEST(turn_on)
    uut.turn_on();
    `FAIL_UNLESS(uut.on === 1);
  `SVTEST_END


  //---------------------------------
  // test: turn_off
  //   we can turn 'on' off using
  //   turn_off() method
  //---------------------------------
  `SVTEST(turn_off)
    uut.turn_off();
    `FAIL_UNLESS(uut.on === 0);
  `SVTEST_END

/*
  ----------------------------------------
  ----------------------------------------

    For more SVUnit, Remember to visit:

         www.AgileSoC.com/svunit


    And try the other SVUnit examples at:

          www.edaplayground.com

  ----------------------------------------
  ----------------------------------------
*/

  `SVUNIT_TESTS_END


  string name = "svunitDemo_ut";
  svunit_testcase svunit_ut;


  //===================================
  // This is the UUT that we're
  // running the Unit Tests on
  //===================================
  svunitOnSwitch uut();


  //===================================
  // Build. Runs once
  //===================================
  function void build();
    svunit_ut = new(name);
  endfunction


  //===================================
  // Setup for running the Unit Tests
  // Runs before every SVTEST.
  //===================================
  task setup();
    svunit_ut.setup();
    /* Place Setup Code Here */
  endtask


  //===================================
  // Here we deconstruct anything we
  // need after running the Unit Tests
  // Runs after every SVTEST.
  //===================================
  task teardown();
    svunit_ut.teardown();
    /* Place Teardown Code Here */
  endtask


endmodule

You can do a lot more than test a simple svunitOnSwith with SVUnit. When you’re ready to test your own design and testbench IP visit: http://www.AgileSoC.com/svunit