Segfault running tests on OS X

[springmeyer]

$ ruby -v
ruby 2.0.0p451 (2014-02-24 revision 45167) [universal.x86_64-darwin13]

Thread 0 Crashed:: Dispatch queue: com.apple.main-thread
0   libsystem_kernel.dylib          0x00007fff90e4e866 __pthread_kill + 10
1   libsystem_pthread.dylib         0x00007fff92ae835c pthread_kill + 92
2   libsystem_c.dylib               0x00007fff88993b1a abort + 125
3   libruby.2.0.0.dylib             0x000000010d5f6d19 rb_bug + 184
4   libruby.2.0.0.dylib             0x000000010d68be9e 0x10d5cd000 + 781982
5   libsystem_platform.dylib        0x00007fff8eaaa5aa _sigtramp + 26
6   ???                             000000000000000000 0 + 0
7   ruby_mapnik.bundle              0x000000010dd20fe4 std::_Rb_tree<Rice::Data_Type<void>*, Rice::Data_Type<void>*, std::_Identity<Rice::Data_Type<void>*>, std::less<Rice::Data_Type<void>*>, std::allocator<Rice::Data_Type<void>*> >::_M_insert_unique(Rice::Data_Type<void>* const&) + 100 (stl_tree.h:200)
8   ruby_mapnik.bundle              0x000000010dd20f57 Rice::Data_Type<void>::Data_Type() + 231 (Data_Type_defn.hpp:77)
9   ruby_mapnik.bundle              0x000000010dd22c9a Rice::Data_Type<mapnik::color> Rice::Data_Type<mapnik::color>::bind<void>(Rice::Module const&) + 602 (Data_Type.ipp:91)
10  ruby_mapnik.bundle              0x000000010dd1ebdb Rice::Data_Type<mapnik::color> Rice::define_class_under<mapnik::color>(Rice::Object, char const*) + 91 (Module_impl.hpp:20)
11  ruby_mapnik.bundle              0x000000010dd1de2b register_color(Rice::Module) + 75 (_mapnik_color.rb.cpp:84)
12  ruby_mapnik.bundle              0x000000010dd1caf2 register_mapnik() + 130 (Module_impl.hpp:20)
13  ruby_mapnik.bundle              0x000000010ddfdb3d Init_ruby_mapnik + 61 (ruby_mapnik.cpp:30)
14  libruby.2.0.0.dylib             0x000000010d5cdcde dln_load + 186

$ gem list

*** LOCAL GEMS ***

addressable (2.3.6, 2.3.5)
backports (3.6.0)
bigdecimal (1.2.5, 1.2.0)
blankslate (3.1.3, 3.1.2, 2.1.2.4)
cairo (1.12.9)
celluloid (0.15.2)
CFPropertyList (2.2.8, 2.2.0)
chunky_png (1.3.1)
classifier (1.3.4)
coderay (1.1.0)
coffee-script (2.2.0)
coffee-script-source (1.7.0)
colorator (0.1)
colored (1.2)
commander (4.2.0, 4.1.6)
diff-lcs (1.2.5)
ethon (0.7.1, 0.7.0, 0.6.3)
execjs (2.2.1, 2.1.0)
faraday (0.9.0, 0.8.9)
faraday_middleware (0.9.1, 0.9.0)
fast-stemmer (1.0.2)
ffi (1.9.3)
gh (0.13.2)
git-up (0.5.12)
grit (2.5.0)
highline (1.6.21)
hitimes (1.2.1)
hoe (3.12.0)
io-console (0.4.2)
jekyll (2.1.0, 2.0.3, 1.5.1, 1.4.3)
jekyll-coffeescript (1.0.0)
jekyll-gist (1.1.0)
jekyll-paginate (1.0.0)
jekyll-sass-converter (1.0.0)
jekyll-watch (1.0.0)
json (1.8.1, 1.7.7)
kramdown (1.4.0, 1.3.3)
launchy (2.4.2)
libxml-ruby (2.7.0, 2.6.0)
liquid (2.6.1, 2.5.5)
listen (2.7.9, 2.7.5, 1.3.1)
maruku (0.7.2, 0.7.1, 0.7.0)
mercenary (0.3.3)
method_source (0.8.2)
mime-types (2.3, 1.25.1)
mini_portile (0.6.0)
minitest (5.3.5, 5.3.4, 4.3.2)
multi_json (1.10.1, 1.9.0)
multipart-post (2.0.0, 1.2.0)
net-http-persistent (2.9.4)
net-http-pipeline (1.0.1)
nokogiri (1.6.2.1, 1.5.6)
parslet (1.6.1, 1.5.0)
pkg-config (1.1.5)
posix-spawn (0.3.8)
pry (0.10.0, 0.9.12.6)
psych (2.0.5, 2.0.0)
pusher-client (0.6.0, 0.4.0)
pygments.rb (0.6.0, 0.5.4)
rake (10.3.2, 0.9.6)
rake-compiler (0.9.2)
rb-fsevent (0.9.4)
rb-inotify (0.9.5, 0.9.4, 0.9.3)
rb-kqueue (0.2.3, 0.2.2)
rdiscount (2.1.7.1, 2.1.7)
rdoc (4.1.1, 4.0.0)
redcarpet (3.1.2, 2.3.0)
rice (1.6.2)
safe_yaml (1.0.3, 1.0.2, 0.9.7)
sass (3.3.9, 3.3.7)
slop (3.5.0, 3.4.7)
sqlite3 (1.3.9, 1.3.7)
test-unit (2.5.5, 2.0.0.0)
timers (3.0.1, 1.1.0)
toml (0.1.1)
travis (1.6.14, 1.6.11, 1.6.8, 1.6.7)
typhoeus (0.6.9, 0.6.8, 0.6.7)
websocket (1.1.4, 1.0.7)
yajl-ruby (1.2.1, 1.2.0, 1.1.0)