fld_write tests fail on windows

[JeffFessler]

some problem with open/close/rm.
here is part of the output from unittest.
as a workaround i will just disable the test on windows for now.

fld-write.jl: Error During Test at D:\a\MIRT.jl\MIRT.jl\test\io\fld-write.jl:65
  Test threw exception
  Expression: fld_write_test1(file, data, endian = endian, raw = raw, check = true, chat = false)
  "file C:\\Users\\RUNNER~1\\AppData\\Local\\Temp\\jl_rA3SWj\\fld-write-test.raw exists"
  Stacktrace:
   [1] fld_write(::String, ::Array{UInt8,1}; check::Bool, dir::String, endian::Symbol, head::Array{String,1}, raw::Bool) at D:\a\MIRT.jl\MIRT.jl\src\io\fld-write.jl:63
   [2] #_args_and_call#25 at D:\buildbot\worker\package_win64\build\usr\share\julia\stdlib\v1.4\Test\src\Test.jl:1293 [inlined]
   [3] fld_write_test1(::String, ::Array{UInt8,1}; raw::Bool, chat::Bool, kwarg::Base.Iterators.Pairs{Symbol,Any,Tuple{Symbol,Symbol},NamedTuple{(:endian, :check),Tuple{Symbol,Bool}}}) at D:\a\MIRT.jl\MIRT.jl\test\io\fld-write.jl:41
   [4] top-level scope at D:\a\MIRT.jl\MIRT.jl\test\io\fld-write.jl:65
   [5] include(::String) at .\client.jl:439
   [6] macro expansion at D:\a\MIRT.jl\MIRT.jl\test\io\z-test.jl:16 [inlined]
   [7] macro expansion at D:\buildbot\worker\package_win64\build\usr\share\julia\stdlib\v1.4\Test\src\Test.jl:1113 [inlined]
   [8] top-level scope at D:\a\MIRT.jl\MIRT.jl\test\io\z-test.jl:16
  
fld-write.jl: Error During Test at D:\a\MIRT.jl\MIRT.jl\test\io\fld-write.jl:65
  Test threw exception

[johnnychen94]

I'm not sure if it helps in solving this issue. But generally, it's a good practice to

• use IOBuffer to avoid direct multiple real IO to the filesystem.
• squash multiple println into one and avoid string interpolation. See https://docs.julialang.org/en/v1/manual/performance-tips/#Avoid-string-interpolation-for-I/O
• not use close explicitly, and instead use the closure version of open, which automatically closes the file when it finishes or when it errors. The philosophy behind this design is RAII; let the context manager(the do-version open) manage the lifetime of the resource.

io = IOBuffer()
ndim = ndims(data)
println(io, "# AVS field file ($(basename(@__FILE__)))")
for line in head
    println(io, "# $line")
end
println(io, "ndim=$ndim")
for ii=1:ndim
    println(io, "dim$ii=$(size(data,ii))")
end
println(io,
    "nspace=", ndim, "\n",
    "veclen=1", "\n",
    "data=", datatype, "\n",
    "field=uniform", "\n")

# only write to disk once
open(file, "w") do fid
    write(fid, take!(io))
end

[JeffFessler]

Thanks for the tip! I've incorporated that suggestion into a PR for AVSfldIO.

BTW, I fixed the fld_write error when developing AVSfldIO by better use of temporary filenames so I can close this issue now.

[johnnychen94]

Clearly that you've worked this issue around.

Just FYI, I just realized that I've also met similar issues, and the workaround is to do GC.gc() before rm (I don't know why, it's perhaps related to Windows temp filesystem):

https://github.com/johnnychen94/DemoCards.jl/blob/66a7917f88813a42ce8116b93b4ee11821d4432a/src/preview.jl#L49-L54