feat: generate test data with junk contents

Also, add "obnam generate-junk" command, for testing this.

Sponsored-by: author

1 files changed, 19 insertions, 0 deletions

diff --git a/obnam-benchmark.md b/obnam-benchmark.md
index 709260d..2fc1452 100644
--- a/obnam-benchmark.md
+++ b/obnam-benchmark.md
@@ -71,6 +71,25 @@ file can describe synthetic benchmarks for different use cases.
 
 # Acceptance criteria
 
+## Generate random data for a backup
+
+_Requirement: The benchmark tool can generate random test data._
+
+We verify this by having the benchmark generate some test data, using
+a subcommand for this purpose. If the data doesn't compress well, we
+assume it's sufficiently random. We can safely assume that the same
+code is used to generate test data for benchmarks, though of course
+the scenario can't verify that. Instead, it can be verified via manual
+code inspection.
+
+~~~scenario
+given an installed Rust program obnam-benchmark
+when I run obnam-benchmark generate-junk 123000 junk.dat
+when I run gzip junk.dat
+then file junk.dat.gz is at least 100100 bytes long
+~~~
+
+
 ## Parses a specification file
 
 _Requirement: The benchmark tool can parse a specification file._