diff --git a/scripts/mbedtls_framework/test_driver.py b/scripts/mbedtls_framework/test_driver.py
index d3878918e..7ea2ccc6d 100644
--- a/scripts/mbedtls_framework/test_driver.py
+++ b/scripts/mbedtls_framework/test_driver.py
@@ -33,50 +33,6 @@ def get_parsearg_base() -> argparse.ArgumentParser:
                         "name defaults to '<DRIVER>-list-vars.cmake'.")
     return parser
 
-def iter_code_files(root: Path) -> Iterable[Path]:
-    """
-    Iterate over all "*.c" and "*.h" files found recursively under the `include`
-    and `src` subdirectories of `root`.
-    """
-    for directory in ("include", "src"):
-        directory_path = root / directory
-        for ext in (".c", ".h"):
-            yield from directory_path.rglob(f"*{ext}")
-
-def get_src_relpaths(builtin: Path, exclude_files: Set[str]) -> List[Path]:
-    """
-    Return the relative paths of all *.c and *.h files under `builtin`,
-    excluding those whose names match any of the patterns in `exclude_files`.
-
-    The returned paths are relative to `builtin`.
-    """
-
-    out = []
-    for file in iter_code_files(builtin):
-        if not any(fnmatch(file.name, pattern) for pattern in exclude_files):
-            out.append(file.relative_to(builtin))
-    out.sort()
-    return out
-
-def get_dst_relpaths(src_relpaths: List[Path], driver: str) -> List[Path]:
-    """
-    Return the relative paths of the *.c and *.h files generated by the script.
-
-    These paths are the same as in `src_relpaths`, except that occurrences of
-    `mbedtls` in `include/mbedtls/...` paths are replaced with `driver`.
-
-    The returned paths are relative to `dst_dir`.
-    """
-
-    out = []
-    for path in src_relpaths:
-        parts = list(path.parts)
-        if parts[0] == "include" and parts[1] == "mbedtls":
-            parts[1] = driver
-        out.append(Path(*parts))
-
-    return out
-
 def run_ctags(file: Path) -> Set[str]:
     """
     Extract the C identifiers in `file` using ctags.
@@ -153,15 +109,15 @@ class TestDriverGenerator:
             raise RuntimeError(f'"src" directory in {src_dir} not found')
 
     def write_list_vars_for_cmake(self, fname: str) -> None:
-        src_relpaths = get_src_relpaths(self.src_dir, self.exclude_files)
+        src_relpaths = self.__iter_src_code_files()
         with open(self.dst_dir / fname, "w") as f:
             f.write(f"set({self.driver}_input_files " + \
                      " ".join(str(path) for path in src_relpaths) + ")\n\n")
             f.write(f"set({self.driver}_files " + \
-                    " ".join(str(path) \
-                    for path in get_dst_relpaths(src_relpaths, self.driver)) + ")\n\n")
+                    " ".join(str(self.__get_dst_relpath(path.relative_to(self.src_dir))) \
+                     for path in src_relpaths) + ")\n\n")
             f.write(f"set({self.driver}_src_files " + \
-                    " ".join(str(path) \
+                    " ".join(str(path.relative_to(self.src_dir)) \
                     for path in src_relpaths if path.suffix == ".c") + ")")
 
     def build_tree(self) -> None:
@@ -203,7 +159,7 @@ class TestDriverGenerator:
             f.relative_to(test_driver_include_dir).as_posix() \
             for f in test_driver_include_dir.rglob("*.h")
         }
-        for f in iter_code_files(self.dst_dir):
+        for f in self.__iter_code_files(self.dst_dir):
             self.__rewrite_inclusions_in_file(f, headers, \
                                               src_include_dir_name, self.driver)
 
@@ -217,7 +173,7 @@ class TestDriverGenerator:
         need to be prefixed.
         """
         identifiers = set()
-        for file in iter_code_files(self.dst_dir):
+        for file in self.__iter_code_files(self.dst_dir):
             identifiers.update(run_ctags(file))
 
         identifiers_with_prefixes = set()
@@ -232,9 +188,20 @@ class TestDriverGenerator:
         with the test driver prefix: <DRIVER>_ for uppercase identifiers,
         and <driver>_ for lowercase ones.
         """
-        for f in iter_code_files(self.dst_dir):
+        for f in self.__iter_code_files(self.dst_dir):
             self.__prefix_identifiers_in_file(f, identifiers_to_prefix, self.driver)
 
+    @staticmethod
+    def __iter_code_files(root: Path) -> Iterable[Path]:
+        """
+        Iterate over all "*.c" and "*.h" files found recursively under the
+        `include` and `src` subdirectories of `root`.
+        """
+        for directory in ("include", "src"):
+            directory_path = root / directory
+            for ext in (".c", ".h"):
+                yield from directory_path.rglob(f"*{ext}")
+
     def __iter_src_code_files(self) -> List[Path]:
         """
         Iterate over all "*.c" and "*.h" files found recursively under the
@@ -243,7 +210,7 @@ class TestDriverGenerator:
         `self.exclude_files`.
         """
         out = []
-        for file in iter_code_files(self.src_dir):
+        for file in self.__iter_code_files(self.src_dir):
             if not any(fnmatch(file.name, pattern) for pattern in self.exclude_files):
                 out.append(file)
         return out