Add coverage tests for stylex extraction

Ultraworked with [Sisyphus](https://github.com/code-yeongyu/oh-my-opencode)

Co-authored-by: Sisyphus <clio-agent@sisyphuslabs.ai>

Author: owjs3901

libs/extractor/src/extractor/extract_style_from_stylex.rs

@@ -323,21 +323,22 @@ fn extract_stylex_dynamic_namespace<'a>(
     if !arrow.expression {
         return None;
     }
-    let stmt = arrow.body.statements.first()?;
-    let Statement::ExpressionStatement(expr_stmt) = stmt else {
-        return None;
-    };
-    // Handle both direct ObjectExpression and ParenthesizedExpression wrapping
-    let body_obj = match &expr_stmt.expression {
-        Expression::ObjectExpression(obj) => obj,
-        Expression::ParenthesizedExpression(paren) => {
-            if let Expression::ObjectExpression(obj) = &paren.expression {
-                obj
-            } else {
-                return None;
-            }
+    // Expression arrow body: Oxc always wraps in ExpressionStatement.
+    // Unwrap ParenthesizedExpression since Oxc preserves parens for `(x) => ({...})`.
+    let body_expr = arrow.body.statements.first().and_then(|stmt| {
+        if let Statement::ExpressionStatement(e) = stmt {
+            Some(&e.expression)
+        } else {
+            None
         }
-        _ => return None,
+    })?;
+    let inner = if let Expression::ParenthesizedExpression(paren) = body_expr {
+        &paren.expression
+    } else {
+        body_expr
+    };
+    let Expression::ObjectExpression(body_obj) = inner else {
+        return None;
     };
 
     // 3. Process each property

libs/extractor/src/lib.rs

@@ -16226,4 +16226,77 @@ const composed = stylex.create({ test: { ...stylex.include(base.empty), color: '
             .unwrap()
         ));
     }
+
+    /// Dynamic namespace with bare expression body (not object): (x) => x
+    /// Covers: extract_style_from_stylex.rs ObjectExpression else branch
+    #[test]
+    #[serial]
+    fn test_stylex_dynamic_bare_expression_body() {
+        reset_class_map();
+        reset_file_map();
+        assert_debug_snapshot!(ToBTreeSet::from(
+            extract(
+                "test.tsx",
+                r#"import stylex from '@stylexjs/stylex';
+const styles = stylex.create({ base: (x) => x });"#,
+                ExtractOption {
+                    package: "@devup-ui/react".to_string(),
+                    css_dir: "@devup-ui/react".to_string(),
+                    single_css: true,
+                    import_main_css: false,
+                    import_aliases: HashMap::new()
+                },
+            )
+            .unwrap()
+        ));
+    }
+
+    /// Dynamic namespace with parenthesized non-object body: (x) => (x)
+    /// Covers: extract_style_from_stylex.rs ParenthesizedExpression unwrap + ObjectExpression else
+    #[test]
+    #[serial]
+    fn test_stylex_dynamic_paren_non_object_body() {
+        reset_class_map();
+        reset_file_map();
+        assert_debug_snapshot!(ToBTreeSet::from(
+            extract(
+                "test.tsx",
+                r#"import stylex from '@stylexjs/stylex';
+const styles = stylex.create({ base: (x) => (x) });"#,
+                ExtractOption {
+                    package: "@devup-ui/react".to_string(),
+                    css_dir: "@devup-ui/react".to_string(),
+                    single_css: true,
+                    import_main_css: false,
+                    import_aliases: HashMap::new()
+                },
+            )
+            .unwrap()
+        ));
+    }
+
+    /// Include-only namespace with no own styles — class_name_str starts empty
+    /// Covers: visit.rs line 332 (class_name_str = included_class when empty)
+    #[test]
+    #[serial]
+    fn test_stylex_include_only_no_own_styles() {
+        reset_class_map();
+        reset_file_map();
+        assert_debug_snapshot!(ToBTreeSet::from(
+            extract(
+                "test.tsx",
+                r#"import stylex from '@stylexjs/stylex';
+const base = stylex.create({ root: { color: 'red' } });
+const composed = stylex.create({ combined: { ...stylex.include(base.root) } });"#,
+                ExtractOption {
+                    package: "@devup-ui/react".to_string(),
+                    css_dir: "@devup-ui/react".to_string(),
+                    single_css: true,
+                    import_main_css: false,
+                    import_aliases: HashMap::new()
+                },
+            )
+            .unwrap()
+        ));
+    }
 }

libs/extractor/src/snapshots/extractor__tests__stylex_dynamic_bare_expression_body.snap

@@ -0,0 +1,8 @@
+---
+source: libs/extractor/src/lib.rs
+expression: "ToBTreeSet::from(extract(\"test.tsx\",\nr#\"import stylex from '@stylexjs/stylex';\nconst styles = stylex.create({ base: (x) => x });\"#,\nExtractOption\n{\n    package: \"@devup-ui/react\".to_string(), css_dir:\n    \"@devup-ui/react\".to_string(), single_css: true, import_main_css: false,\n    import_aliases: HashMap::new()\n},).unwrap())"
+---
+ToBTreeSet {
+    styles: {},
+    code: "import stylex from \"@stylexjs/stylex\";\nconst styles = { \"base\": \"\" };\n",
+}

libs/extractor/src/snapshots/extractor__tests__stylex_dynamic_paren_non_object_body.snap

@@ -0,0 +1,8 @@
+---
+source: libs/extractor/src/lib.rs
+expression: "ToBTreeSet::from(extract(\"test.tsx\",\nr#\"import stylex from '@stylexjs/stylex';\nconst styles = stylex.create({ base: (x) => (x) });\"#,\nExtractOption\n{\n    package: \"@devup-ui/react\".to_string(), css_dir:\n    \"@devup-ui/react\".to_string(), single_css: true, import_main_css: false,\n    import_aliases: HashMap::new()\n},).unwrap())"
+---
+ToBTreeSet {
+    styles: {},
+    code: "import stylex from \"@stylexjs/stylex\";\nconst styles = { \"base\": \"\" };\n",
+}

libs/extractor/src/snapshots/extractor__tests__stylex_include_only_no_own_styles.snap

@@ -0,0 +1,19 @@
+---
+source: libs/extractor/src/lib.rs
+expression: "ToBTreeSet::from(extract(\"test.tsx\",\nr#\"import stylex from '@stylexjs/stylex';\nconst base = stylex.create({ root: { color: 'red' } });\nconst composed = stylex.create({ combined: { ...stylex.include(base.root) } });\"#,\nExtractOption\n{\n    package: \"@devup-ui/react\".to_string(), css_dir:\n    \"@devup-ui/react\".to_string(), single_css: true, import_main_css: false,\n    import_aliases: HashMap::new()\n},).unwrap())"
+---
+ToBTreeSet {
+    styles: {
+        Static(
+            ExtractStaticStyle {
+                property: "color",
+                value: "red",
+                level: 0,
+                selector: None,
+                style_order: None,
+                layer: None,
+            },
+        ),
+    },
+    code: "import \"@devup-ui/react/devup-ui.css\";\nimport stylex from \"@stylexjs/stylex\";\nconst base = { \"root\": \"a\" };\nconst composed = { \"combined\": \"a\" };\n",
+}