Пофиксил эту проблему так:
plugins: [require('karma-babel-preprocessor')],
но появился новый баг:
karma start test/karma.conf.js
/home/finom/Dropbox/Public/sync/ag/my/github/matreshka_develop/node_modules/karma/node_modules/di/lib/injector.js:9
throw error('No provider for "' + name + '"!');
^
Error: No provider for "framework:jasmine"! (Resolving: framework:jasmine)
at error (/home/finom/Dropbox/Public/sync/ag/my/github/matreshka_develop/node_modules/karma/node_modules/di/lib/injector.js:22:68)
at Object.parent.get (/home/finom/Dropbox/Public/sync/ag/my/github/matreshka_develop/node_modules/karma/node_modules/di/lib/injector.js:9:13)
at get (/home/finom/Dropbox/Public/sync/ag/my/github/matreshka_develop/node_modules/karma/node_modules/di/lib/injector.js:54:19)
at /home/finom/Dropbox/Public/sync/ag/my/github/matreshka_develop/node_modules/karma/lib/server.js:133:20
at Array.forEach (native)
at Server._start (/home/finom/Dropbox/Public/sync/ag/my/github/matreshka_develop/node_modules/karma/lib/server.js:132:21)
at invoke (/home/finom/Dropbox/Public/sync/ag/my/github/matreshka_develop/node_modules/karma/node_modules/di/lib/injector.js:75:15)
at Server.start (/home/finom/Dropbox/Public/sync/ag/my/github/matreshka_develop/node_modules/karma/lib/server.js:97:18)
at Object.exports.run (/home/finom/Dropbox/Public/sync/ag/my/github/matreshka_develop/node_modules/karma/lib/cli.js:231:26)
at requireCliAndRun (/usr/lib/node_modules/karma-cli/bin/karma:44:16)
at /usr/lib/node_modules/karma-cli/bin/karma:54:12
at /usr/lib/node_modules/karma-cli/node_modules/resolve/lib/async.js:44:21
at ondir (/usr/lib/node_modules/karma-cli/node_modules/resolve/lib/async.js:187:31)
at /usr/lib/node_modules/karma-cli/node_modules/resolve/lib/async.js:153:39
at onex (/usr/lib/node_modules/karma-cli/node_modules/resolve/lib/async.js:93:22)
at /usr/lib/node_modules/karma-cli/node_modules/resolve/lib/async.js:24:18
Без указания препроцессора работает прекрасно (скрипты компилируются напрямую коммандой babel). karma-jasmine конечно же установлен.