Feature Test Specification

Seamonkey (5.0)
Browser Imaging (Black Box)

 
Written by: <Eli Goldberg>

History:

Date	Change Description	Revision	Updated By
<12/28/98>	Skeleton test plan	0.5	eli@netscape.com
<1/4/98>	Added some muscular tissue.	0.6	eli@netscape.com
<5/5/98>	First draft. <Submitted to review by Pam Nunn and Beth Epperson.>	1.0	eli@netscape.com
<5/7/99>	Beth's feedback incorporated	1.0.1	eli@netscape.com
<8/6/99>	Revised.	1.1	eli@netscape.com

References:
UI and/or Functional Specifications: 

PNG (Portable Network Graphics) Home Site
Imagelib: The Image Library
Pam's Imaging Testing Notes (Stored on a Netscape internal server; list of image files and suggested testing equivalence classes.)

Other:

Pam Nunn's publish/pngpix directory on Jazz (Stored on a Netscape internal server; contains some sample PNG files, some docs)
James Cape's PNG test suite

"Browser Imaging" consists testing end-user imaging. Testing of imaging-related HTML elements (e.g. IMG, MAP & AREA) is covered by the Browser Standards Compliance team.

Will-Test Areas/Testing Strategy:

Testing of browser imaging emphasizes destructive testing, as well as the "use cases" that are unlikely to regularly appear in casual, daily usage. The component testing strategy is to assume that the multitudes of Mozilla users will cover the most frequent use cases, allowing testing to focus on the bugs that Mozilla testers are less likely to encounter from casual usage.

Won't-Test Areas:

Imagelib's interaction with CSS & XML will not be tested; testing of whether images invoked by CSS or XML tags should be covered by the individuals testing CSS and XML. Likewise, imaging from within Java or JavaScript applets will not be tested.

Special Areas:

• PNG (an extremely well-architected and documented new lossless image format, positioned as a replacement for the aging GIF format). Our having excellent support for the PNG format in Seamonkey will be a huge boon to the format's adoption.
  
  Greg Roelofs has been actively providing feedback on the PNG implementation, and has volunteered to assist in seeking out and coordinating net community members interested in testing Seamonkey's PNG support.
  
  Since the format's originators and proponents are far more qualified to evaluate the quality of our implementation than the author of this test plan, when the implementation is more finalized, we should work with Greg (and the png-discuss list) to solicit useful bug reports. (Of course, taking into account the constraints of our resources to implement, and noting that major additional feature work will only be possible if contributed by net volunteers.)
  
  Image Display
  1. Natively handled Image Formats
     1. PNG
     2. GIF
     3. GIF87
     4. GIF (animated) - single and multiple
     5. JPEG/jfif
        
        
  2. Non-natively handled Image Formats
     1. XBM
        
        
  3. Stress Tests
     1. Confirm proper display (or rejection) of a few equivalence classes of invalid or unusual GIFs.
        
        
  4. Miscellaneous Scenarios
     1. Proper dithering at 8 & 16-bit resolutions cross-platform.
     2. Proper display of cached images (including when loading the image file as document, rather than when embedded within a page)
        
        

1. Imaging Interactions
   1. Dynamic screen bit-depth & resolution changes, especially to lower bit depths.

Future Testing Directions: (re-evaluate around M12 or so)

1. what parts of PNG, JPEG & GIF are we supporting and not supporting? (pnunn)
2. Imaging aspects of "Page Info" (when implemented)
3. Expand bad-img-gif to cover additional equivalence classes listed by Pam. (noted in the test case)
4. Create a suite (or apply Pam's suite) of negative JPEG & PNG image test cases, to see how we handle different types of invalid images.