tensorflow.rb: Spec fails unpredictably

For some reason the string data spec fails. When I run it for the first time I get these results:

/Users/sebastiandeutsch/.rbenv/versions/2.3.1/bin/ruby -I/Users/sebastiandeutsch/.rbenv/versions/2.3.1/lib/ruby/gems/2.3.0/gems/rspec-core-3.4.2/lib:/Users/sebastiandeutsch/.rbenv/versions/2.3.1/lib/ruby/gems/2.3.0/gems/rspec-support-3.4.1/lib /Users/sebastiandeutsch/.rbenv/versions/2.3.1/lib/ruby/gems/2.3.0/gems/rspec-core-3.4.2/exe/rspec --pattern spec/\*\*\{,/\*/\*\*\}/\*_spec.rb
............................................F

Failures:

  1) Tensorflow::Tensor Should make tensor of string data type.
     Failure/Error: expect(["Ruby", "Tensorflow", "is", "cool"]).to match_array(Tensorflow::string_reader(input1.tensor))

       expected collection contained:  ["", "Ruby", "Tensorf\xD8F7", "\xD6\x94\xAE\x99\x7F\x00\x00\xC0%\x84\xAF\x99\x7F\x00\x00\x04\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x03\x00\x06<\xF8\x9A\xF9\a\x00\xF0\xBE\x0F\xF8\x9A\xF9\a\x000\x00\x00\x00\x00\x00\x00\x000\x00\x00\x00\x00\x00\x00\x000\x1D\x00\x8F\xAF\x99\x7F\x00\x00\x00"]
       actual collection contained:    ["Ruby", "Tensorflow", "cool", "is"]
       the missing elements were:      ["", "Tensorf\xD8F7", "\xD6\x94\xAE\x99\x7F\x00\x00\xC0%\x84\xAF\x99\x7F\x00\x00\x04\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x03\x00\x06<\xF8\x9A\xF9\a\x00\xF0\xBE\x0F\xF8\x9A\xF9\a\x000\x00\x00\x00\x00\x00\x00\x000\x00\x00\x00\x00\x00\x00\x000\x1D\x00\x8F\xAF\x99\x7F\x00\x00\x00"]
       the extra elements were:        ["Tensorflow", "cool", "is"]
     # ./spec/tensor_spec.rb:19:in `block (2 levels) in <top (required)>'

Finished in 0.42225 seconds (files took 0.32834 seconds to load)
45 examples, 1 failure

Failed examples:

rspec ./spec/tensor_spec.rb:17 # Tensorflow::Tensor Should make tensor of string data type.

/Users/sebastiandeutsch/.rbenv/versions/2.3.1/bin/ruby -I/Users/sebastiandeutsch/.rbenv/versions/2.3.1/lib/ruby/gems/2.3.0/gems/rspec-core-3.4.2/lib:/Users/sebastiandeutsch/.rbenv/versions/2.3.1/lib/ruby/gems/2.3.0/gems/rspec-support-3.4.1/lib /Users/sebastiandeutsch/.rbenv/versions/2.3.1/lib/ruby/gems/2.3.0/gems/rspec-core-3.4.2/exe/rspec --pattern spec/\*\*\{,/\*/\*\*\}/\*_spec.rb failed

When I run it again I get this error:

/Users/sebastiandeutsch/.rbenv/versions/2.3.1/bin/ruby -I/Users/sebastiandeutsch/.rbenv/versions/2.3.1/lib/ruby/gems/2.3.0/gems/rspec-core-3.4.2/lib:/Users/sebastiandeutsch/.rbenv/versions/2.3.1/lib/ruby/gems/2.3.0/gems/rspec-support-3.4.1/lib /Users/sebastiandeutsch/.rbenv/versions/2.3.1/lib/ruby/gems/2.3.0/gems/rspec-core-3.4.2/exe/rspec --pattern spec/\*\*\{,/\*/\*\*\}/\*_spec.rb
............................................ruby(7394,0x7fff774d5000) malloc: *** mach_vm_map(size=140481453690880) failed (error code=3)
*** error: can't allocate region
*** set a breakpoint in malloc_error_break to debug
libc++abi.dylib: terminating with uncaught exception of type std::bad_alloc: std::bad_alloc
/Users/sebastiandeutsch/.rbenv/versions/2.3.1/bin/ruby -I/Users/sebastiandeutsch/.rbenv/versions/2.3.1/lib/ruby/gems/2.3.0/gems/rspec-core-3.4.2/lib:/Users/sebastiandeutsch/.rbenv/versions/2.3.1/lib/ruby/gems/2.3.0/gems/rspec-support-3.4.1/lib /Users/sebastiandeutsch/.rbenv/versions/2.3.1/lib/ruby/gems/2.3.0/gems/rspec-core-3.4.2/exe/rspec --pattern spec/\*\*\{,/\*/\*\*\}/\*_spec.rb failed
rake aborted!
TypeError: no implicit conversion from nil to integer
/Users/sebastiandeutsch/.rbenv/versions/2.3.1/bin/bundle:23:in `load'
/Users/sebastiandeutsch/.rbenv/versions/2.3.1/bin/bundle:23:in `<main>'
Tasks: TOP => spec
(See full trace by running task with --trace)

I’m running OSX (El Capitain)

ruby 2.3.1p112 (2016-04-26 revision 54768) [x86_64-darwin15] using rbenv
tensorflow at d2c913aa9b7cb63e466392f76d46ac5fbc1e9825