Uniform decimal digits for test runs summary / PrettyTables.pretty_table

[fingolfin]

At the end of our test suite, we print a table with the slowest test files, which is quite useful.

┌────────────────────────────────────────────────────────┬──────────────┬───────────────┬─────────────────┬───────────────────┐
│                                               Filename │ Runtime in s │ + Compilation │ + Recompilation │ Allocations in MB │
├────────────────────────────────────────────────────────┼──────────────┼───────────────┼─────────────────┼───────────────────┤
│                        test/Modules/UngradedModules.jl │      1372.22 │       20.0326 │             0.0 │           3340.99 │
│     test/AlgebraicGeometry/Schemes/elliptic_surface.jl │      445.162 │       165.269 │             0.0 │         1.25646e5 │
│    experimental/FTheoryTools/test/literature_models.jl │      223.246 │        4.6469 │             0.0 │           82457.4 │
│          experimental/FTheoryTools/test/tate_models.jl │      129.353 │       16.4472 │             0.0 │           69563.8 │
│              test/PolyhedralGeometry/linear_program.jl │      72.8957 │       0.98791 │             0.0 │           95.7083 │
│                  test/PolyhedralGeometry/polyhedron.jl │       64.557 │        17.781 │             0.0 │           13058.2 │
│        test/AlgebraicGeometry/Schemes/CoveredScheme.jl │       60.829 │       11.9376 │        0.415924 │           8449.28 │
│              test/AlgebraicGeometry/Schemes/Tjurina.jl │      60.8095 │       11.6399 │             0.0 │           16785.6 │
│   test/AlgebraicGeometry/Schemes/DerivedPushforward.jl │      55.5698 │       24.6313 │             0.0 │           17213.6 │
│ experimental/LieAlgebras/test/LieAlgebraModule-test.jl │      50.2391 │       14.9335 │             0.0 │           30064.8 │
└────────────────────────────────────────────────────────┴──────────────┴───────────────┴─────────────────┴───────────────────┘

But I think it would be even better if we used a fixed number of decimal digits after the period (1 or 2), and no scientific format.

That makes it easier to take in how the entries related in size at a glance. Like this (I didn't bother rounding correctly):

┌────────────────────────────────────────────────────────┬──────────────┬───────────────┬─────────────────┬───────────────────┐
│                                               Filename │ Runtime in s │ + Compilation │ + Recompilation │ Allocations in MB │
├────────────────────────────────────────────────────────┼──────────────┼───────────────┼─────────────────┼───────────────────┤
│                        test/Modules/UngradedModules.jl │      1372.22 │         20.03 │             0.0 │            3340.9 │
│     test/AlgebraicGeometry/Schemes/elliptic_surface.jl │       445.16 │        165.26 │             0.0 │          125646.0 │
│    experimental/FTheoryTools/test/literature_models.jl │       223.24 │          4.64 │             0.0 │           82457.4 │
│          experimental/FTheoryTools/test/tate_models.jl │       129.35 │         16.44 │             0.0 │           69563.8 │
│              test/PolyhedralGeometry/linear_program.jl │        72.89 │          0.98 │             0.0 │              95.7 │
│                  test/PolyhedralGeometry/polyhedron.jl │        64.55 │         17.78 │             0.0 │           13058.2 │
│        test/AlgebraicGeometry/Schemes/CoveredScheme.jl │        60.82 │         11.93 │             0.4 │            8449.2 │
│              test/AlgebraicGeometry/Schemes/Tjurina.jl │        60.80 │         11.63 │             0.0 │           16785.6 │
│   test/AlgebraicGeometry/Schemes/DerivedPushforward.jl │        55.56 │         24.63 │             0.0 │           17213.6 │
│ experimental/LieAlgebras/test/LieAlgebraModule-test.jl │        50.23 │         14.93 │             0.0 │           30064.8 │
└────────────────────────────────────────────────────────┴──────────────┴───────────────┴─────────────────┴───────────────────┘

The relevant code for this in test/runtest.jl:

function print_stats(io::IO, stats_dict::Dict; fmt=PrettyTables.tf_unicode, max=50)
  sorted = sort(collect(stats_dict), by=x->x[2].time, rev=true)
  println(io, "### Stats per file")
  println(io)
  table = hcat(first.(sorted), permutedims(reduce(hcat, collect.(values.(last.(sorted))))))
  formatters = nothing
  if haskey(first(values(stats_dict)), :ctime)
    header=[:Filename, Symbol("Runtime in s"), Symbol("+ Compilation"), Symbol("+ Recompilation"), Symbol("Allocations in MB")]
    #formatters = PrettyTables.ft_printf("%.2f%%", [3,4])
  else
    header=[:Filename, Symbol("Time in s"), Symbol("Allocations in MB")]
  end
  PrettyTables.pretty_table(io, table; tf=fmt, max_num_of_rows=max, header=header, formatters=formatters)
end