Tests failing

[ablaom]

Started on #47 but having problem getting the current release to pass tests:

     Testing Running tests...
Test Summary: | Pass  Total
types         |   15     15
┌ Warning: Error parsing "<wf cmd=verify_tag pos=VBP ot=notag>'ve</wf>". AssertionError("No parser for \"<wf cmd=verify_tag pos=VBP ot=notag>'ve</wf>\"")
└ @ CorpusLoaders ~/.julia/packages/CorpusLoaders/RkzqR/src/apply_subparsers.jl:23
Test Summary: | Pass  Total
SemCor        |   35     35
Test Summary: | Pass  Total
Senseval3     |    4      4
Test Summary: | Pass  Total
CoNLL         |    9      9
Test Summary: | Pass  Total
CoNLL2000     |    7      7
basic use train_pos: Test Failed at /Users/anthony/.julia/packages/CorpusLoaders/RkzqR/test/test_IMDB.jl:15
  Expression: typeof(words) == Vector{String}
   Evaluated: Vector{Any} == Vector{String}

Stacktrace:
  [1] macro expansion
    @ ~/.julia/packages/CorpusLoaders/RkzqR/test/test_IMDB.jl:15 [inlined]
  [2] top-level scope
    @ /Users/julia/buildbot/worker/package_macos64/build/usr/share/julia/stdlib/v1.6/Test/src/Test.jl:1226
  [3] include(fname::String)
    @ Base.MainInclude ./client.jl:444
  [4] macro expansion
    @ ~/.julia/packages/CorpusLoaders/RkzqR/test/runtests.jl:20 [inlined]
  [5] top-level scope
    @ /Users/julia/buildbot/worker/package_macos64/build/usr/share/julia/stdlib/v1.6/Test/src/Test.jl:1226
  [6] include(fname::String)
    @ Base.MainInclude ./client.jl:444
  [7] top-level scope
    @ none:6
  [8] eval
    @ ./boot.jl:360 [inlined]
  [9] exec_options(opts::Base.JLOptions)
    @ Base ./client.jl:261
 [10] _start()
    @ Base ./client.jl:485
basic use train_pos: Test Failed at /Users/anthony/.julia/packages/CorpusLoaders/RkzqR/test/test_IMDB.jl:18
  Expression: typeof(sentences) == #= /Users/anthony/.julia/packages/CorpusLoaders/RkzqR/test/test_IMDB.jl:18 =# @NestedVector(String, 2)
   Evaluated: Vector{Any} == Vector{Vector{String}}
Stacktrace:
  [1] macro expansion
    @ ~/.julia/packages/CorpusLoaders/RkzqR/test/test_IMDB.jl:18 [inlined]
  [2] top-level scope
    @ /Users/julia/buildbot/worker/package_macos64/build/usr/share/julia/stdlib/v1.6/Test/src/Test.jl:1226
  [3] include(fname::String)
    @ Base.MainInclude ./client.jl:444
  [4] macro expansion
    @ ~/.julia/packages/CorpusLoaders/RkzqR/test/runtests.jl:20 [inlined]
  [5] top-level scope
    @ /Users/julia/buildbot/worker/package_macos64/build/usr/share/julia/stdlib/v1.6/Test/src/Test.jl:1226
  [6] include(fname::String)
    @ Base.MainInclude ./client.jl:444
  [7] top-level scope
    @ none:6
  [8] eval
    @ ./boot.jl:360 [inlined]
  [9] exec_options(opts::Base.JLOptions)
    @ Base ./client.jl:261
 [10] _start()
    @ Base ./client.jl:485
basic use train_pos: Error During Test at /Users/anthony/.julia/packages/CorpusLoaders/RkzqR/test/test_IMDB.jl:19
  Test threw exception
  Expression: sum(length.(sentences)) == length(words)
  MethodError: no method matching zero(::Type{Any})
  Closest candidates are:
    zero(::Type{Union{Missing, T}}) where T at missing.jl:105
    zero(::Union{Type{P}, P}) where P<:Dates.Period at /Users/julia/buildbot/worker/package_macos64/build/usr/share/julia/stdlib/v1.6/Dates/src/periods.jl:53
    zero(::SparseArrays.AbstractSparseArray) at /Users/julia/buildbot/worker/package_macos64/build/usr/share/julia/stdlib/v1.6/SparseArrays/src/SparseArrays.jl:55
    ...
  Stacktrace:
    [1] zero(#unused#::Type{Any})
      @ Base ./missing.jl:106
    [2] reduce_empty(#unused#::typeof(+), #unused#::Type{Any})
      @ Base ./reduce.jl:311
    [3] reduce_empty(#unused#::typeof(Base.add_sum), #unused#::Type{Any})
      @ Base ./reduce.jl:320
    [4] mapreduce_empty(#unused#::typeof(identity), op::Function, T::Type)
      @ Base ./reduce.jl:343
    [5] reduce_empty(op::Base.MappingRF{typeof(identity), typeof(Base.add_sum)}, #unused#::Type{Any})
      @ Base ./reduce.jl:329
    [6] reduce_empty_iter
      @ ./reduce.jl:355 [inlined]
    [7] mapreduce_empty_iter(f::Function, op::Function, itr::Vector{Any}, ItrEltype::Base.HasEltype)
      @ Base ./reduce.jl:351
    [8] _mapreduce(f::typeof(identity), op::typeof(Base.add_sum), #unused#::IndexLinear, A::Vector{Any})
      @ Base ./reduce.jl:400
    [9] _mapreduce_dim
      @ ./reducedim.jl:318 [inlined]
   [10] #mapreduce#672
      @ ./reducedim.jl:310 [inlined]
   [11] mapreduce
      @ ./reducedim.jl:310 [inlined]
   [12] #_sum#682
      @ ./reducedim.jl:878 [inlined]
   [13] _sum
      @ ./reducedim.jl:878 [inlined]
   [14] #_sum#681
      @ ./reducedim.jl:877 [inlined]
   [15] _sum
      @ ./reducedim.jl:877 [inlined]
   [16] #sum#679
      @ ./reducedim.jl:873 [inlined]
   [17] sum(a::Vector{Any})
      @ Base ./reducedim.jl:873
   [18] macro expansion
      @ ~/.julia/packages/CorpusLoaders/RkzqR/test/test_IMDB.jl:19 [inlined]
   [19] top-level scope
      @ /Users/julia/buildbot/worker/package_macos64/build/usr/share/julia/stdlib/v1.6/Test/src/Test.jl:1226
   [20] include(fname::String)
      @ Base.MainInclude ./client.jl:444
   [21] macro expansion
      @ ~/.julia/packages/CorpusLoaders/RkzqR/test/runtests.jl:20 [inlined]
   [22] top-level scope
      @ /Users/julia/buildbot/worker/package_macos64/build/usr/share/julia/stdlib/v1.6/Test/src/Test.jl:1226
   [23] include(fname::String)
      @ Base.MainInclude ./client.jl:444
   [24] top-level scope
      @ none:6
   [25] eval
      @ ./boot.jl:360 [inlined]
   [26] exec_options(opts::Base.JLOptions)
      @ Base ./client.jl:261
   [27] _start()
      @ Base ./client.jl:485
basic use train_pos: Test Failed at /Users/anthony/.julia/packages/CorpusLoaders/RkzqR/test/test_IMDB.jl:21
  Expression: typeof(flatten_levels(docs, (!lvls)(IMDB, :documents)) |> full_consolidate) == Vector{String}
   Evaluated: Vector{Any} == Vector{String}
Stacktrace:
  [1] macro expansion
    @ ~/.julia/packages/CorpusLoaders/RkzqR/test/test_IMDB.jl:21 [inlined]
  [2] top-level scope
    @ /Users/julia/buildbot/worker/package_macos64/build/usr/share/julia/stdlib/v1.6/Test/src/Test.jl:1226
  [3] include(fname::String)
    @ Base.MainInclude ./client.jl:444
  [4] macro expansion
    @ ~/.julia/packages/CorpusLoaders/RkzqR/test/runtests.jl:20 [inlined]
  [5] top-level scope
    @ /Users/julia/buildbot/worker/package_macos64/build/usr/share/julia/stdlib/v1.6/Test/src/Test.jl:1226
  [6] include(fname::String)
    @ Base.MainInclude ./client.jl:444
  [7] top-level scope
    @ none:6
  [8] eval
    @ ./boot.jl:360 [inlined]
  [9] exec_options(opts::Base.JLOptions)
    @ Base ./client.jl:261
 [10] _start()
    @ Base ./client.jl:485
basic use train_pos: Test Failed at /Users/anthony/.julia/packages/CorpusLoaders/RkzqR/test/test_IMDB.jl:22
  Expression: typeof(flatten_levels(docs, (!lvls)(IMDB, :sentences)) |> full_consolidate) == Vector{String}
   Evaluated: Vector{Any} == Vector{String}
Stacktrace:
  [1] macro expansion
    @ ~/.julia/packages/CorpusLoaders/RkzqR/test/test_IMDB.jl:22 [inlined]
  [2] top-level scope
    @ /Users/julia/buildbot/worker/package_macos64/build/usr/share/julia/stdlib/v1.6/Test/src/Test.jl:1226
  [3] include(fname::String)
    @ Base.MainInclude ./client.jl:444
  [4] macro expansion
    @ ~/.julia/packages/CorpusLoaders/RkzqR/test/runtests.jl:20 [inlined]
  [5] top-level scope
    @ /Users/julia/buildbot/worker/package_macos64/build/usr/share/julia/stdlib/v1.6/Test/src/Test.jl:1226
  [6] include(fname::String)
    @ Base.MainInclude ./client.jl:444
  [7] top-level scope
    @ none:6
  [8] eval
    @ ./boot.jl:360 [inlined]
  [9] exec_options(opts::Base.JLOptions)
    @ Base ./client.jl:261
 [10] _start()
    @ Base ./client.jl:485
Test Summary:         | Pass  Fail  Error  Total
IMDB                  |   19     4      1     24
  basic use train_pos |    1     4      1      6
  basic use train_neg |    6                   6
  basic use test_pos  |    6                   6
  basic use test_neg  |    6                   6
Test Summary:         | Pass  Fail  Error  Total
IMDB                  |   19     4      1     24
  basic use train_pos |    1     4      1      6
  basic use train_neg |    6                   6
  basic use test_pos  |    6                   6
  basic use test_neg  |    6                   6
ERROR: LoadError: Some tests did not pass: 19 passed, 4 failed, 1 errored, 0 broken.
in expression starting at /Users/anthony/.julia/packages/CorpusLoaders/RkzqR/test/runtests.jl:19

caused by: Some tests did not pass: 19 passed, 4 failed, 1 errored, 0 broken.
ERROR: Package CorpusLoaders errored during testing

(jl_4k2h6c) pkg> st
      Status `/private/var/folders/4n/gvbmlhdc8xj973001s6vdyw00000gq/T/jl_4k2h6c/Project.toml`
  [214a0ac2] CorpusLoaders v0.3.2

julia> versioninfo()
Julia Version 1.6.0
Commit f9720dc2eb (2021-03-24 12:55 UTC)
Platform Info:
  OS: macOS (x86_64-apple-darwin19.6.0)
  CPU: Intel(R) Core(TM) i7-8850H CPU @ 2.60GHz
  WORD_SIZE: 64
  LIBM: libopenlibm
  LLVM: libLLVM-11.0.1 (ORCJIT, skylake)
Environment:
  JULIA_LTS_PATH = /Applications/Julia-1.0.app/Contents/Resources/julia/bin/julia
  JULIA_PATH = /Applications/Julia-1.6.app/Contents/Resources/julia/bin/julia
  JULIA_EGLOT_PATH = /Applications/Julia-1.5.app/Contents/Resources/julia/bin/julia
  JULIA_NUM_THREADS = 5
  JULIA_NIGHTLY_PATH = /Applications/Julia-1.7.app/Contents/Resources/julia/bin/julia

[oxinabox]

Weird.
I wonder if it i a bug here, or in MultiResolutionIterators.jl.

Could it be that the IMDB data isn't loading an an empty collection can't infer?