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tests/TC036-file-read-random.md

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+# Test Case: Random Regular-File Reads
+
+**Test ID**: TC036-file-read-random
+
+## Objective
+
+Verify independent start, middle, and end `pread(2)` ranges from a deterministic
+1 MiB regular file.
+
+## Fixture
+
+Use `images/flat.erofs`, `source/flat/random-test.bin`, and the three
+`expected/random-*.bin` files. Evidence asserts layout 0 and exact size.
+
+## Procedure
+
+```sh
+./read_probe pread "$mnt/random-test.bin" 0 10240 /tmp/tc036-start
+./read_probe pread "$mnt/random-test.bin" 512000 10240 /tmp/tc036-mid
+./read_probe pread "$mnt/random-test.bin" 1024000 24576 /tmp/tc036-end
+cmp /tmp/repo22-g1/expected/random-start.bin /tmp/tc036-start
+cmp /tmp/repo22-g1/expected/random-mid.bin /tmp/tc036-mid
+cmp /tmp/repo22-g1/expected/random-end.bin /tmp/tc036-end
+sha256 /tmp/tc036-start /tmp/tc036-mid /tmp/tc036-end
+```
+
+## Expected Results
+
+- Every bounded `pread` reports its requested byte count and exact offset.
+- All three ranges match independently generated source ranges; cleanup passes.