test(plugin): compare a plugin-provided installer against upstream Composer

The fixture plugin registers an InstallerInterface implementation of its own
and installs a package of a custom type with it, recording every contract
call it receives. A fresh install produces a byte-identical project tree on
both implementations, trace included.

A second test pins the divergence a re-run and a `remove` expose: the two
implementations consult getInstaller at different points, so the trace
order — and its length once `remove` re-creates the Composer instance —
differs. It is written in full and marked ignored rather than trimmed.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>

1 files changed, 32 insertions, 0 deletions

diff --git a/crates/shirabe/tests/plugin/fixtures/e2e-installer/project/composer.json b/crates/shirabe/tests/plugin/fixtures/e2e-installer/project/composer.json
new file mode 100644
index 00000000..64c1bb32
--- /dev/null
+++ b/crates/shirabe/tests/plugin/fixtures/e2e-installer/project/composer.json
@@ -0,0 +1,32 @@
+{
+    "name": "shirabe/e2e-installer",
+    "description": "E2E fixture project: install a custom package type through a plugin-provided installer.",
+    "repositories": [
+        {
+            "type": "path",
+            "url": "../plugin",
+            "options": {
+                "symlink": false
+            }
+        },
+        {
+            "type": "path",
+            "url": "../packages/*",
+            "options": {
+                "symlink": false
+            }
+        },
+        {
+            "packagist.org": false
+        }
+    ],
+    "require": {
+        "shirabe-test/asset-installer": "1.0.0",
+        "shirabe-test/asset-a": "1.0.0"
+    },
+    "config": {
+        "allow-plugins": {
+            "shirabe-test/asset-installer": true
+        }
+    }
+}