Overview
"Test" is the first block in Redstone CG. It was used to find out how to change blocks texture when a Redstone Signal was applied. When Redstone Signal level greater than 0 was applied to it, the texture changed to "Test On" blocks texture. "Test On" is the second block, with no functionality - used as a placeholder for a texture and a model.
Both blocks have served their purpose since even before the release of 0.0.0, but kept until 0.1.0 (inclusive).
Obtaining
These were only obtainable with commands:
/give @s redstonecg:test
/give @s redstonecg:test_on