Integration: keep the ATN contract tests, drop the extra workflow (#7561)

The contract tests no longer compiled on main (AtnItem::dictionary is now
Vec<u8>, so it is compared with b"Future event"), sat outside main's
tests/it layout, and the new atn.yml added six legs (two macOS) to every
PR against ci.yml's policy. Move the tests into tests/it so the existing
CI runs them, drop atn.yml and docs/atn-testing.md, keep main's ci.yml and
fuzz target, and note the committed fixtures in ATTRIBUTION.md.

Co-authored-by: denstu473 <63150090+denstu473@users.noreply.github.com>
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

crates/psd/fuzz/fuzz_targets/atn.rs

@@ -1,12 +1,14 @@
 //! Fuzz the `.atn` actions parser: any input must return `Ok` or `Err`, never panic, and
-//! anything that parses must survive writing, reparsing and stable canonical writing.
+//! anything that parses must survive a write and parse back equal.
 #![no_main]
 
 use libfuzzer_sys::fuzz_target;
-
-#[path = "../../tests/common/atn_roundtrip.rs"]
-mod atn_roundtrip;
+use photocraft_psd::atn;
 
 fuzz_target!(|data: &[u8]| {
-    atn_roundtrip::check(data);
+    if let Ok(f) = atn::parse(data) {
+        let bytes = atn::write(&f).expect("a parsed set is writable");
+        let again = atn::parse(&bytes).expect("a written set parses");
+        assert_eq!(again.actions, f.actions);
+    }
 });

crates/psd/tests/fixtures/atn/README.md

@@ -13,7 +13,7 @@ oracles.
 | `descriptors.atn` | 859 | Every descriptor value variant and every reference form currently represented by the parser | `6c76502822c1f36c8060a71adb227c4540663518785bbab1b70951dac0ef58ad` |
 | `float-bits.atn` | 428 | NaN payload, negative zero, infinities, and floats inside lists, objects and arrays | `0aa6278a569c777f249b305e889896132c2a87e44a24cb1a55d1d3fc0928fd0c` |
 
-`tests/atn_contract.rs` checks the independently encoded bytes and expected public structures.
-The ATN fuzz job copies the same files into its seed corpus. A fixture change should explain
+`tests/it/atn_contract.rs` checks the independently encoded bytes and expected public structures.
+A fixture change should explain
 the changed wire fields and update this table; do not regenerate expectations merely to make a
 failing parser pass.

crates/psd/tests/it/atn_contract.rs

@@ -1,4 +1,4 @@
-//! Portable public-API contract, executed natively in debug and release by ATN CI.
+//! Public-API contract for the `.atn` parser, against independently encoded wire fixtures.
 use photocraft_psd::PsdError;
 use photocraft_psd::atn::{self, AtnAction, AtnEvent, AtnFile, AtnItem};
 use photocraft_psd::descriptor::{Class, Descriptor, Id, MAX_DEPTH, ObjectArray, ReferenceItem, UnicodeString, Value};
@@ -7,10 +7,10 @@ use photocraft_psd::descriptor::{Class, Descriptor, Id, MAX_DEPTH, ObjectArray,
 mod atn_roundtrip;
 
 const FIXTURES: &[(&str, &[u8])] = &[
-    ("empty", include_bytes!("fixtures/atn/empty.atn")),
-    ("metadata", include_bytes!("fixtures/atn/metadata.atn")),
-    ("descriptors", include_bytes!("fixtures/atn/descriptors.atn")),
-    ("float bits", include_bytes!("fixtures/atn/float-bits.atn")),
+    ("empty", include_bytes!("../fixtures/atn/empty.atn")),
+    ("metadata", include_bytes!("../fixtures/atn/metadata.atn")),
+    ("descriptors", include_bytes!("../fixtures/atn/descriptors.atn")),
+    ("float bits", include_bytes!("../fixtures/atn/float-bits.atn")),
 ];
 
 fn file_with(desc: Descriptor) -> AtnFile {
@@ -55,7 +55,7 @@ fn unicode_metadata_unknown_events_and_dialog_flags_are_preserved() {
     let future = &action.items[1];
     assert_eq!(future.event, AtnEvent::Name("syntheticFutureEvent".into()));
     assert_eq!((future.expanded, future.enabled, future.with_dialog, future.dialog_options), (false, false, true, 255));
-    assert_eq!(future.dictionary, "Future event");
+    assert_eq!(future.dictionary, b"Future event");
     assert!(future.descriptor.is_none());
     assert_eq!(file.actions[1].name, UnicodeString::new_nul("Empty"));
     assert!(file.actions[1].items.is_empty());

crates/psd/tests/it/common/atn_roundtrip.rs

@@ -1,4 +1,4 @@
-//! Shared invariant for the parser contract suite and the actual cargo-fuzz target.
+//! Shared round-trip invariant for the `.atn` parser contract suite.
 use photocraft_psd::atn::{self, AtnFile};
 use photocraft_psd::descriptor::{Descriptor, Value};
 

crates/psd/tests/it/main.rs

@@ -1,5 +1,6 @@
 //! The crate's integration tests, linked into one test binary.
 
+mod atn_contract;
 mod builder;
 mod corpus;
 mod corpus_atn;