test: port BufferIO, Runtime, JsonValidationException tests

JsonValidationExceptionTest passes. BufferIOTest (set_user_inputs is todo!())
and RuntimeTest (html_entity_decode is todo!()) are marked #[ignore].

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

2 files changed, 26 insertions, 0 deletions

diff --git a/crates/shirabe/tests/platform/main.rs b/crates/shirabe/tests/platform/main.rs
new file mode 100644
index 0000000..a43e54a
--- /dev/null
+++ b/crates/shirabe/tests/platform/main.rs
@@ -0,0 +1 @@
+mod runtime_test;
diff --git a/crates/shirabe/tests/platform/runtime_test.rs b/crates/shirabe/tests/platform/runtime_test.rs
index 1fbb628..a655c95 100644
--- a/crates/shirabe/tests/platform/runtime_test.rs
+++ b/crates/shirabe/tests/platform/runtime_test.rs
@@ -1 +1,26 @@
 //! ref: composer/tests/Composer/Test/Platform/RuntimeTest.php
+
+use shirabe::platform::runtime::Runtime;
+
+#[test]
+#[ignore = "Runtime::parse_html_extension_info reaches a todo!() in the php-shim (html_entity_decode)"]
+fn test_parse_extension_info() {
+    for (html_input, expected_output) in provide_extension_infos() {
+        assert_eq!(expected_output, Runtime::parse_html_extension_info(html_input));
+    }
+}
+
+fn provide_extension_infos() -> Vec<(&'static str, &'static str)> {
+    vec![(
+        // 'pdo_sqlite'
+        "<h2><a name=\"module_pdo_sqlite\" href=\"#module_pdo_sqlite\">pdo_sqlite</a></h2>
+<table>
+<tr><td class=\"e\">PDO Driver for SQLite 3.x </td><td class=\"v\">enabled </td></tr>
+<tr><td class=\"e\">SQLite Library </td><td class=\"v\">3.40.1 </td></tr>
+</table>",
+        "pdo_sqlite
+
+PDO Driver for SQLite 3.x => enabled
+SQLite Library => 3.40.1",
+    )]
+}