I can't produce a capx right now (computer down), but if I remember well, the JSON for an array in C2 is 3 dimensional in the datas, as the array is. So you would have to load it with :
{"c2array":true,"size":[3,1,1],"data":[[["test1"]],[["test2"]],[["test3"]]]}
and not :
{"c2array":true,"size":[3,1,1],"data":["test1","test2","test3"]}
witch is consistant with your current result (taking the [0][0] of a string is the first letter)