Expand test suite

[Yehyoung Kang]

It would be nice to expand our test suite and test our library more rigorously. I don't have a clear plan, so I'm open to suggestions.

Some ideas:

Opening file

• Fail: Empty file
• Fail: File is too large (>2GB)

File Header

• Fail: File Header is too small/truncated
• Fail: Normal file with invalid signature (not ‘8BPS’, e.g. ‘FAIL’)
• Fail: Normal file with lowercase signature (‘8bps’)
• Fail: Normal file with invalid version (not 1)
  • PSB uses version number 2
• Fail: Reserved segment contains nonzero values
• Fail: Number of channels exceeds max (>56)
• Fail: Image height > 30000
  • PSB has image height limit of 300,000
• Fail: Image width > 30000
  • PSB has image width limit of 300,000
• Fail: Invalid bits per channel (not in { 1, 8, 16, 32 })
• Fail: Invalid color mode (not in { 0, 1, 2, 3, 4, 7, 8, 9 })

Color Mode

• Fail: Missing or truncated color mode section
• Success: Non-(indexed (2) or duotone (8)) image has empty Color Mode section
• Fail: Non-indexed/duotone image has non-empty Color Mode section
• Fail: Indexed image has invalid color table size (not 768)
• ???: Duotone images have undocumented format—do we want to handle this?
  • Other apps should ignore/preserve this section if the image is duotone

Resources

• Fail: Missing or truncated resources section

Resource block

• Fail: Resource block is too small/truncated
• Fail: Resource block has invalid signature (not ‘8BIM’)
• Fail: Resource block has lowercase signature (‘8bim’)
• Fail: Resource block has duplicate ID
• Fail: Resource block has unknown ID value
(see https://www.adobe.com/devnet-apps/photoshop/fileformatashtml/#50577409_38034 for list of valid IDs)
• Fail: Resource block name string is invalid
• Fail: Resource block name string is not padded with zero (should we even check this?)
• Fail: Resource data section is invalid (need more info)

Layer and Mask

• Fail: L&M is missing or truncated

Layer Info

• Fail: Layer length is not a multiple of 2
• Fail: Layer info section is missing or truncated
• Fail: Layer records are bad
• Fail: Channel image data is bad

Layer Record

• Fail: Blend mode signature is invalid (not ‘8BIM’)
• Fail: Blend mode key is unknown (see Layer records for the full list)
• Fail: Clipping value is invalid
• Fail: Bits 5~7 are nonzero (should we even check this?)
• Fail: Filler is nonzero

Layer mask/adjustment layer data

• Fail: Length is not one of 0, 20, 36
• Fail: Default color is neither 0 or 255
• Fail: Bits 5~7 are nonzero (should we even check this?)

Layer blending ranges

• Fail: Section is missing or truncated

Channel Image Data

• Fail: Invalid compression method (not one of 0, 1, 2, 3)
• Fail: Image data is missing or truncated

Additional Layer Info

• Fail: ALI section is missing or truncated
• Fail: Unknown key (see

Global layer mask info

• Fail: Section is missing or truncated
• Fail: Length is too short (< 13)

Image Data

• Fail: Invalid compression method
• Fail: Missing or truncated compressed data
• Fail: Compressed data does not match compression method