What standards do we need to follow while testing aesthetic conditions of a program? Is there any particular set of rules/standards to follow? That is, if we are writing test cases for a program, what do we need to keep in mind for testing? This is difficult because everyone has their own aesthetic sense.
I think some of those 'aesthetic conditions' you refer to can be measured, but to prevent subjective opinions from taking over, I'd analyse them rather as a consequence of measuring usability.
You can test how easily a user locates information, how likely he/she is to click on a call to action. I think it's ok to assume that, if not necessarily beautiful, an easy to use interface will probably mean a pleasing interface (good distribution of elements, readability, white space, consistency, etc).
UX tests allow for feedback, too. I've run and taken 5-minute tests that asked for ratings on 'aesthetic beauty', using direct or indirect questions.
I don't think there is a set of rules, but there has been some interesting work around the subject:
From Interaction Design Foundation's Visual Aesthetics in human-computer interaction and interaction design, the conclussion reads:
As was pointed out by Tractinsky, the visual judgment on beauty is very fast, thus plays an important role in drawing the attention of customers. And the visual beauty is dominated by rather simple and traditional rules. But too much emphasis on the beauty will lead to a difficult-to-use designs
The article divides aesthetic input as subjective quality characteristics: Beauty, pleasure or hedonic attributes; and the objective quality characteristics: Usability, functionality, performance, reliability, safety, and maintenability.
Even if a product is attractively designed and have an acceptable level of objective quality, that product will be useless if it doesn't have a meaning.
You define your own standards by the needs and opinions of YOUR PRODUCT's end-users. No other standards for software aesthetics testing exist or matter.
If you really care about how the looks of your software will affect your end-users, I suggest you gather as much feedback from them as possible.