diff --git a/scripts/mbedtls_dev/test_case.py b/scripts/mbedtls_dev/test_case.py
new file mode 100644
index 000000000..8ef18510c
--- /dev/null
+++ b/scripts/mbedtls_dev/test_case.py
@@ -0,0 +1,88 @@
+"""Library for generating Mbed TLS test data.
+"""
+
+# Copyright The Mbed TLS Contributors
+# SPDX-License-Identifier: Apache-2.0
+#
+# Licensed under the Apache License, Version 2.0 (the "License"); you may
+# not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+# http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+# WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+import binascii
+from typing import Any, List, Optional
+import typing_extensions #pylint: disable=import-error
+
+class Writable(typing_extensions.Protocol):
+    """Abstract class for typing hints."""
+    # pylint: disable=no-self-use,too-few-public-methods,unused-argument
+    def write(self, text: str) -> Any:
+        ...
+
+
+def hex_string(data: bytes) -> str:
+    return '"' + binascii.hexlify(data).decode('ascii') + '"'
+
+
+class MissingDescription(Exception):
+    pass
+
+class MissingFunction(Exception):
+    pass
+
+class TestCase:
+    """An Mbed TLS test case."""
+
+    def __init__(self, description: Optional[str] = None):
+        self.comments = [] #type: List[str]
+        self.description = description #type: Optional[str]
+        self.dependencies = [] #type: List[str]
+        self.function = None #type: Optional[str]
+        self.arguments = [] #type: List[str]
+
+    def add_comment(self, *lines: str) -> None:
+        self.comments += lines
+
+    def set_description(self, description: str) -> None:
+        self.description = description
+
+    def set_dependencies(self, dependencies: List[str]) -> None:
+        self.dependencies = dependencies
+
+    def set_function(self, function: str) -> None:
+        self.function = function
+
+    def set_arguments(self, arguments: List[str]) -> None:
+        self.arguments = arguments
+
+    def check_completeness(self) -> None:
+        if self.description is None:
+            raise MissingDescription
+        if self.function is None:
+            raise MissingFunction
+
+    def write(self, out: Writable) -> None:
+        """Write the .data file paragraph for this test case.
+
+        The output starts and ends with a single newline character. If the
+        surrounding code writes lines (consisting of non-newline characters
+        and a final newline), you will end up with a blank line before, but
+        not after the test case.
+        """
+        self.check_completeness()
+        assert self.description is not None # guide mypy
+        assert self.function is not None # guide mypy
+        out.write('\n')
+        for line in self.comments:
+            out.write('# ' + line + '\n')
+        out.write(self.description + '\n')
+        if self.dependencies:
+            out.write('depends_on:' + ':'.join(self.dependencies) + '\n')
+        out.write(self.function + ':' + ':'.join(self.arguments) + '\n')