max / makenotwork

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1	//! Seal: every file in `static/bases/` still hashes to the name it is filed
2	//! under, and the README table lists exactly those files.
3	//!
4	//! The directory is a content-addressed mirror of the font bases `quasi-type`
5	//! pins, served by the `/static` `ServeDir` with no route of its own. Nothing
6	//! else in the server reads it, so a rename, a truncation or a flipped byte
7	//! ships without a compile error and without a failing request: the mirror
8	//! answers 404 or serves bytes that fail `quasi-type`'s own digest check, and
9	//! every Alloy build silently falls back to the upstream host the mirror exists
10	//! to stop depending on.
11	//!
12	//! Hashing four files costs nothing, and the name already states the expected
13	//! answer, so the check needs no fixture and no constant to maintain.
14	//!
15	//! Run with: cargo test --test bases_mirror
16
17	use std::fmt::Write as _;
18	use std::fs;
19	use std::path::{Path, PathBuf};
20
21	use sha2::{Digest, Sha256};
22
23	const BASES_DIR: &str = "static/bases";
24
25	/// The mirror's files, README excluded, sorted by name.
26	fn mirrored_files() -> Vec<PathBuf> {
27	let dir = Path::new(env!("CARGO_MANIFEST_DIR")).join(BASES_DIR);
28	let mut out: Vec<PathBuf> = fs::read_dir(&dir)
29	.expect("static/bases/ is readable")
30	.map(\|entry\| entry.expect("readable dir entry").path())
31	.filter(\|path\| path.is_file())
32	.filter(\|path\| path.file_name().is_some_and(\|n\| n != "README.md"))
33	.collect();
34	out.sort();
35	out
36	}
37
38	fn sha256_hex(bytes: &[u8]) -> String {
39	Sha256::digest(bytes)
40	.iter()
41	.fold(String::new(), \|mut out, b\| {
42	let _ = write!(out, "{b:02x}");
43	out
44	})
45	}
46
47	fn file_name(path: &Path) -> String {
48	path.file_name()
49	.expect("mirror path has a file name")
50	.to_string_lossy()
51	.into_owned()
52	}
53
54	#[test]
55	fn every_mirrored_base_is_named_by_its_digest() {
56	let files = mirrored_files();
57	assert!(
58	!files.is_empty(),
59	"static/bases/ holds no mirrored files. An empty mirror sends every \
60	Alloy build back to the upstream host.",
61	);
62
63	let mut wrong: Vec<String> = Vec::new();
64	for path in &files {
65	let name = file_name(path);
66	let bytes = fs::read(path).expect("read mirrored base");
67	let digest = sha256_hex(&bytes);
68	if digest != name {
69	wrong.push(format!("{name} hashes to {digest}"));
70	}
71	}
72
73	assert!(
74	wrong.is_empty(),
75	"mirrored files whose name is not their sha256: {wrong:?}\n\
76	`quasi-type` fetches by digest, so a file filed under any other name \
77	is unreachable. Rename it to the digest reported here, or restore the \
78	bytes if they were corrupted.",
79	);
80	}
81
82	#[test]
83	fn readme_table_lists_exactly_the_mirrored_files() {
84	let readme = Path::new(env!("CARGO_MANIFEST_DIR"))
85	.join(BASES_DIR)
86	.join("README.md");
87	let text = fs::read_to_string(&readme).expect("static/bases/README.md is readable");
88
89	// Table rows are `\| `<digest>` \| <upstream file> \|`; the digest is the only
90	// backticked field on a row that starts one.
91	let mut documented: Vec<String> = text
92	.lines()
93	.filter_map(\|line\| line.strip_prefix("\| `"))
94	.filter_map(\|rest\| rest.split('`').next())
95	.map(str::to_owned)
96	.collect();
97	documented.sort();
98
99	let present: Vec<String> = mirrored_files().iter().map(\|p\| file_name(p)).collect();
100
101	assert_eq!(
102	documented, present,
103	"the README table and static/bases/ disagree.\n\
104	Adding a base to `pins.toml` means adding its files here and a row \
105	each; the row says which upstream file the digest is.",
106	);
107	}
108