Added test case to check the length of a sliced TransformedCorpus.
Added test case to check the length of a sliced TransformedCorpus.

mattilyra/gensim,dsquareindia/gensim,gojomo/gensim,bhargavvader/gensim,summanlp/gensim,robotcator/gensim,ziky90/gensim,jaksmid/gensim,akutuzov/gensim,akutuzov/gensim,akutuzov/gensim,markroxor/gensim,macks22/gensim,quole/gensim,isohyt/gensim,robotcator/gensim,jaksmid/gensim,laic/gensim,ELind77/gensim,manasRK/gensim,ziky90/gensim,piskvorky/gensim,quole/gensim,manasRK/gensim,macks22/gensim,davechallis/gensim,ELind77/gensim,piskvorky/gensim,pombredanne/gensim,loisaidasam/gensim,Kreiswolke/gensim,bhargavvader/gensim,ELind77/gensim,loisaidasam/gensim,RaRe-Technologies/gensim,pombredanne/gensim,piskvorky/gensim,Kreiswolke/gensim,zachmayer/gensim,davechallis/gensim,summanlp/gensim,markroxor/gensim,olavurmortensen/gensim,zachmayer/gensim,ziky90/gensim,dsquareindia/gensim,laic/gensim,mattilyra/gensim,pombredanne/gensim,dsquareindia/gensim,olavurmortensen/gensim,davechallis/gensim,markroxor/gensim,loisaidasam/gensim,summanlp/gensim,tzoiker/gensim,laic/gensim,isohyt/gensim,robotcator/gensim,quole/gensim,zachmayer/gensim,olavurmortensen/gensim,RaRe-Technologies/gensim,manasRK/gensim,RaRe-Technologies/gensim,jaksmid/gensim,tzoiker/gensim,tzoiker/gensim,Kreiswolke/gensim,RaRe-Technologies/gensim,macks22/gensim,bhargavvader/gensim,gojomo/gensim,gojomo/gensim,gojomo/gensim,isohyt/gensim,mattilyra/gensim