1 files changed, 22 insertions, 2 deletions

diff --git a/test/lib/ansible_test/_internal/io.py b/test/lib/ansible_test/_internal/io.py
index 8daa4dda01..0f61cd2df2 100644
--- a/test/lib/ansible_test/_internal/io.py
+++ b/test/lib/ansible_test/_internal/io.py
@@ -41,9 +41,20 @@ def make_dirs(path):  # type: (str) -> None
             raise
 
 
-def write_json_file(path, content, create_directories=False, formatted=True):  # type: (str, t.Union[t.List[t.Any], t.Dict[str, t.Any]], bool, bool) -> None
+def write_json_file(path,  # type: str
+                    content,  # type: t.Union[t.List[t.Any], t.Dict[str, t.Any]]
+                    create_directories=False,  # type: bool
+                    formatted=True,  # type: bool
+                    encoder=None,  # type: t.Optional[t.Callable[[t.Any], t.Any]]
+                    ):  # type: (...) -> None
     """Write the given json content to the specified path, optionally creating missing directories."""
-    text_content = json.dumps(content, sort_keys=formatted, indent=4 if formatted else None, separators=(', ', ': ') if formatted else (',', ':')) + '\n'
+    text_content = json.dumps(content,
+                              sort_keys=formatted,
+                              indent=4 if formatted else None,
+                              separators=(', ', ': ') if formatted else (',', ':'),
+                              cls=encoder,
+                              ) + '\n'
+
     write_text_file(path, text_content, create_directories=create_directories)
 
 
@@ -72,3 +83,12 @@ def open_binary_file(path, mode='rb'):  # type: (str, str) -> t.BinaryIO
 
     # noinspection PyTypeChecker
     return io.open(to_bytes(path), mode)
+
+
+class SortedSetEncoder(json.JSONEncoder):
+    """Encode sets as sorted lists."""
+    def default(self, obj):  # pylint: disable=method-hidden, arguments-differ
+        if isinstance(obj, set):
+            return sorted(obj)
+
+        return super(SortedSetEncoder).default(self, obj)