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libv - assert_equal, str, etc.

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procedure assert_equal (
    prefix'event : string;
     got, expected : integer;
    level : severity_level := error) is
begin
  assert got = expected
    report prefix & " wrong. Got " & integer'image(got) & " expected "
    & integer'image(expected)
    & "(difference=" & integer'image(got-expected) &")"
    severity level; end procedure assert_equal;

In addition, the same API can be used for comparing more complex types (like the integer_vector type which is also part of libv):

procedure assert_equal ( prefix : string;
                         got, expected : integer_vector;
                         level : severity_level := error) is
  variable g,e : integer;
begin -- procedure assert_equal
  assert got'length = expected'length
      report prefix & " length wrong. Got " & integer'image(got'length)
      & " expected " & integer'image(expected'length)
      & "(difference=" & integer'image(got'length-expected'length) &")"
  severity level;
  for i in 0 to got'length-1 loop
     g := got(got'low+i);
     e := expected(expected'low+i);
     assert g = e
       report prefix & " got(" & integer'image(got'low+i) & ") = "
       & integer'image(g) & CR
       & " expected(" & integer'image(expected'low+i)
       & ") = " & integer'image(e)
       severity level;
  end loop; -- i
end procedure assert_equal;

or indeed a similar function for `pixel_array`:

procedure assert_equal (
prefix : string;
expected, got : pixel_array;
level : severity_level := error) is
begin -- procedure assert_equal
    assert_equal(prefix & "(width)", expected'length(1), got'length(1), level);
    assert_equal(prefix & "(height)", expected'length(2), got'length(2), level);
    for y in expected'range(2) loop
       for x in expected'range(1) loop
          assert expected(x,y)=got(x,y)
            report prefix &"(" & str(x) & "," & str(y)  &")" &
                str(expected(x,y)) & "/=" & str(got(x,y))
            severity level;
       end loop; -- x
    end loop; -- y
end procedure assert_equal;

You’ll notice I got bored of writing integer'image and wrote a str function which takes an integer and an optional length argument and returns a string, left-padded with spaces if the length argument is longer than the integer requires:

 function str (val : integer; length : natural := 0) return string is
   constant chars_needed : natural := num_chars(val);
   variable s : string(1 to max(length, chars_needed)) := (others => ' ');
 begin -- function str
    if length = 0 then
       return integer'image(val);
    end if;
    if chars_needed > length then
       report "Can't fit " & integer'image(val) & " into "
              & integer'image(length) & " character(s) - returning full width"
              severity warning;
       return integer'image(val);
    end if;
    s(s'high-(chars_needed-1) to s'high) := integer'image(val);
    return s;
end function str;

Again, this can be a standard API and we can have a str function for other types; For example, boolean:

 function str (val : boolean; length:natural range 0 to 1 := 0) return string is
 begin -- function str
     if length = 0 then
       return boolean'image(val);
     end if;
     if length = 1 then
       if val then
         return "T";
       else
         return "F";
       end if;
     end if;
 end function str;