test(plugin): compare a real-plugin install against upstream Composer

Run upstream Composer and Shirabe over pristine copies of a fixture
project at the same path and require composer.lock, the whole vendor tree
(including the plugin-generated GeneratedConfig.php), the plugin's IO
lines and the exit code to match byte for byte.

The plugin under test (phpstan/extension-installer 1.4.3) is downloaded by
fixtures/e2e/fetch — pinned to an upstream commit and hash-verified — into
a git-ignored directory rather than committed; the test skips while it is
absent, like the other real-PHP prerequisites. Its dependencies are
minimal stand-ins resolved from local repositories, so test runs stay
offline. A zip dist would exercise the known lossy-string byte-precision
debt in RemoteFilesystem, so the fixture serves the plugin through a path
dist until that is resolved.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

1 files changed, 5 insertions, 0 deletions

diff --git a/crates/shirabe/tests/plugin/fixtures/e2e/packages/phpstan-phpstan/composer.json b/crates/shirabe/tests/plugin/fixtures/e2e/packages/phpstan-phpstan/composer.json
new file mode 100644
index 00000000..cbd11818
--- /dev/null
+++ b/crates/shirabe/tests/plugin/fixtures/e2e/packages/phpstan-phpstan/composer.json
@@ -0,0 +1,5 @@
+{
+    "name": "phpstan/phpstan",
+    "version": "2.1.0",
+    "description": "Minimal stand-in for phpstan/phpstan used by the extension-installer E2E fixture."
+}