A test is a term used to refer to the shell of sea urchins, and also the shell of certain microorganisms, such as testate foraminifera and testate amoebae. In ascidians the test is composed largely of cellulose (historically termed “tunicine”). From 1845 (when this was discovered by Schmidt) until 1958 (when cellulose fibres were found in mammalian connective tissue), ascidians were studied under the belief to be the only animals that synthesised cellulose.