add different caching structures to inverted_index tests
add different caching structures to inverted_index tests

saq7/MeTA,esparza83/meta,gef756/meta,husseinhazimeh/meta,gef756/meta,esparza83/meta,gef756/meta,gef756/meta,gef756/meta,esparza83/meta,husseinhazimeh/meta,esparza83/meta,husseinhazimeh/meta,saq7/MeTA,husseinhazimeh/meta,saq7/MeTA,husseinhazimeh/meta,esparza83/meta