[ThomasWaldmann]

Adds tests for the fixed chunker reading from a pipe / FIFO, see #10565.

Reading via the OS-level file handle of a pipe gives short reads, and posix_fadvise() fails with ESPIPE there (e.g. on Linux). master already handles both: short reads since #10166, and posix_fadvise() errors via safe_fadvise(). But no test covered the fixed chunker reading from a pipe. borg 1.4 and 1.2 had both bugs: #10563 / #10564.

• fixed_test.py: new test_chunkify_pipe, chunks a pipe's file handle with ChunkerFixed, with a writer that pauses between bursts.
• test_create_read_special_big_fifo: now also runs with --chunker-params=fixed,1048576.

Checked on Linux: with the bare os.posix_fadvise() call put back into dread(), test_chunkify_pipe fails with OSError: [Errno 29] Illegal seek; with the current code all tests pass.

🤖 Generated with Claude Code

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 89.35%. Comparing base (144a83b) to head (184cae0).
⚠️ Report is 5 commits behind head on master.
✅ All tests successful. No failed tests found.

Additional details and impacted files

@@            Coverage Diff             @@
##           master   #10568      +/-   ##
==========================================
+ Coverage   89.34%   89.35%   +0.01%     
==========================================
  Files         104      104              
  Lines       20091    20091              
  Branches     3154     3154              
==========================================
+ Hits        17950    17953       +3     
+ Misses       1484     1481       -3     
  Partials      657      657              

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