docs: name the tools that are actually required
flac and magick were both required and neither was listed. flac is the one that matters most: it is what proves an archived file is intact, and without it a truncated download is promoted as a master because ffmpeg reports nothing. It ships with metaflac, so it arrives with any flac package. Also points at the edge-case fixtures, which are a different set from the ordinary ones and answer a different question.
diff --git a/README.md b/README.md
@@ -27,9 +27,15 @@ produces a clean, consistently tagged, consistently named library: lossless mast
## Requirements
-- `ffmpeg`, `metaflac`, `vorbiscomment`
+- `ffmpeg`, `metaflac`, `flac`, `vorbiscomment`
+- `magick` (ImageMagick), for measuring, optimising and generating cover art
- `chafa` is optional, for previews on terminals without Kitty graphics
+`flac` is not optional in practice: it is what proves an archived file is intact.
+ffmpeg decodes a truncated flac without reporting anything at all, so without the
+reference decoder a half-finished download would be promoted as a master.
+`flac` ships with `metaflac`, so it comes along with a flac package.
+
## Usage
```sh
@@ -90,6 +96,13 @@ scripts/make-fixtures.sh # into ~/music/staging
scripts/make-fixtures.sh /tmp/staging # or anywhere else
```
+`scripts/make-edge-fixtures.sh` builds a second set for the opposite purpose:
+the shapes downloads actually arrive in, rather than tidy ones. Nested album
+folders, CD1/CD2 folders, junk cover art, truncated files, text files wearing an
+audio extension, every sidecar a rip ships with, and names built from emoji,
+zero-width characters or nothing but punctuation. Each case carries an `EDGE.md`
+saying what is odd about it and what intake is expected to do.
+
It is idempotent and takes a couple of seconds. Each fixture directory has a `FIXTURE.md`
saying what it tests and what the expected behaviour is.