Please refer, Article by Ralph daniels (JCE, Vol.37, No.4, 1960 link: https://pubs.acs.org/doi/abs/10.1021/ed037p205). According to this paper, even acetaldehyde is not oxidised by Fehlings solution. They claim these are errors in the text books are carried over for many years.
In this journal, the authors observations are:
Category-1 :Positive fehling test: Glucose and other reducing sugars,glyoxal & pyruvic aldehyde (both of them does not have alpha H).
Category-II: Acetaldehyde, crotnaldehyde, cinnamaldehyde, these aldehydes show a colour change, but they have not observed the presence of Cu+1 in the reaction, (the aldehyde group is not oxidised,hence it is false positive test.)
Negative fehling test: Benzaldehyde other aromatic aldehydes, isobutraldehyde.