Verbose test output with highlighted differences

New to Julia
1

Is there a way to get more verbose output from @test failures? Take this minimal example:

julia> expected = [1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21]
julia> result = [1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 99, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21]
julia> @test expected == result

Test Failed at REPL[3]:1
  Expression: expected == result
   Evaluated: [1, 2, 3, 4, 5, 6, 7, 8, 9, 10  …  12, 13, 14, 15, 16, 17, 18, 19, 20, 21] == [1, 2, 3, 4, 5, 6, 7, 8, 9, 10  …  12, 13, 14, 15, 16, 17, 18, 19, 20, 21]

The long vectors are truncated, but this unfortunately hides the element that’s different.

Compare to pytest in python:

def test_foo():
  expected = [1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21]
  result = [1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 99, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21]
  assert expected == result

<snip>
>     assert expected == result
E     assert [1, 2, 3, 4, 5, 6, ...] == [1, 2, 3, 4, 5, 6, ...]
E       
E       At index 10 diff: 11 != 99
E       Use -v to get more diff

Running pytest -vv also prints the full diff of the two arrays:

  Full diff:
    [
        1,
        2,
        3,
        4,
        5,
        6,
        7,
        8,
        9,
        10,
  -     99,
  +     11,
        12,
        13,
        14,
        15,
        16,
        17,
        18,
        19,
        20,
        21,
    ]

Is there a way to get similar output with Test.jl, or another package (e.g. rust’s pretty_assertions)? I’m using TestItemRunner.jl if that helps.

1 Like
2

There’s WhyNotEqual.jl:

julia> using WhyNotEqual

julia> whynot(==, expected, result)
DifferentAndNoChildren: When applying `lens` to both objects, we get `obj1` and `obj2`.
obj1 and obj2 are different, but they don't have any children.
lens: (@o _[11])
obj1: 11
obj2: 99
1 Like