diff --git a/tests/scripts/generate_psa_tests.py b/tests/scripts/generate_psa_tests.py
old mode 100644
new mode 100755
index 8e57f01..da15d84
--- a/tests/scripts/generate_psa_tests.py
+++ b/tests/scripts/generate_psa_tests.py
@@ -230,12 +230,14 @@
     def __init__(self, *, description: str, **kwargs) -> None:
         super().__init__(**kwargs)
         self.description = description #type: str
+        self.usage = self.original_usage #type: psa_storage.Expr
+
 class StorageKeyBuilder:
-    def __init__(self) -> None:
-        pass
+    def __init__(self, usage_extension: bool) -> None:
+        self.usage_extension = usage_extension #type: bool
 
     def build(self, **kwargs) -> StorageKey:
-        return StorageKey(**kwargs)
+        return StorageKey(usage_extension = self.usage_extension, **kwargs)
 
 class StorageFormat:
     """Storage format stability test cases."""
@@ -253,7 +255,7 @@
         self.constructors = info.constructors #type: macro_collector.PSAMacroEnumerator
         self.version = version #type: int
         self.forward = forward #type: bool
-        self.key_builder = StorageKeyBuilder() #type: StorageKeyBuilder
+        self.key_builder = StorageKeyBuilder(usage_extension = True) #type: StorageKeyBuilder
 
     def make_test_case(self, key: StorageKey) -> test_case.TestCase:
         """Construct a storage format test case for the given key.
@@ -467,6 +469,24 @@
     def __init__(self, info: Information) -> None:
         super().__init__(info, 0, False)
 
+    def all_keys_for_usage_flags(self) -> List[StorageKey]:
+        """Generate test keys covering usage flags."""
+        # First generate keys without usage policy extension for
+        # compatibility testing, then generate the keys with extension
+        # to check the extension is working.
+        keys = [] #type: List[StorageKey]
+        prev_builder = self.key_builder
+
+        self.key_builder = StorageKeyBuilder(usage_extension = False)
+        keys += super().all_keys_for_usage_flags(extra_desc = 'without extension')
+
+        self.key_builder = StorageKeyBuilder(usage_extension = True)
+        keys += super().all_keys_for_usage_flags(extra_desc = 'with extension')
+
+        self.key_builder = prev_builder
+        return keys
+
+
 class TestGenerator:
     """Generate test data."""