Test Engeneer's Day on September 9

9 September 1947 (sometimes erroneously reported as 1945) - the day when "First actual case of bug being found."

In 1947, Grace Murray Hopper was working on the Harvard University Mark II Aiken Relay Calculator (a primitive computer).
On the 9th of September, 1947, when the machine was experiencing problems, an investigation showed that there was a moth trapped between the points of Relay #70, in Panel F.
The operators removed the moth and affixed it to the log. (See the picture above.) The entry reads: "First actual case of bug being found."

Let's selebrate Test Engineer's Day on September 9!