下文是有关微体古生物学文献中的一段文字，不管是百度还是知网，都查不到红色字体tests的意思，感觉应该是类似于shells之类的东西。请赐教！谢谢！

Foramanifera comprise one of the most diverse groups of microscopic protists in the modern ocean. Many of these protozoans, members of the eukaryotic super-kingdom Rhizaria, develop a variety of carbonate biominerals as shells, or tests. Of the 15 foraminiferal orders recognized by the micropaleontological community, seven are capable of secreting calcite exoskeletons (Sen Gupta, 1999; Armstrong and Brasier, 2006). Others mineralize aragonite and opaline silica, and two groups can assemble foreign particles into tests using carbonate or organic matter as cements.

非常感谢刘进平老师赐教！

刘进平老师：tests：动物的甲壳，介壳，或被囊