Move sentinel truthy test away from test/narrow.rs

Author: hrolfurgylfa

pyrefly/lib/test/narrow.rs

@@ -3288,21 +3288,6 @@ def f(x: int | bool | MISSING):
     "#,
 );
 
-testcase!(
-    sentinel_is_truthy,
-    r#"
-from typing_extensions import Sentinel
-from typing import Literal, assert_type
-
-MISSING = Sentinel("MISSING")
-x: MISSING | None = MISSING
-if x:
-    assert_type(x, MISSING)
-else:
-    assert_type(x, None)
-    "#,
-);
-
 testcase!(
     sentinel_narrow_with_type_param,
     r#"

pyrefly/lib/test/sentinel.rs

@@ -234,3 +234,18 @@ MISSING = Sentinel("MISSING")
 MISSING.__name__  # E: Object of class `Sentinel` has no attribute `__name__`
     "#,
 );
+
+testcase!(
+    sentinel_is_truthy,
+    r#"
+from typing_extensions import Sentinel
+from typing import Literal, assert_type
+
+MISSING = Sentinel("MISSING")
+x: MISSING | None = MISSING
+if x:
+    assert_type(x, MISSING)
+else:
+    assert_type(x, None)
+    "#,
+);