Refactor WASM binding directory structure

* All tests moved into wasm/codegen/tests folder
* Merged wasm/codegen/helpers/ into wasm/codegen/generators/

PiperOrigin-RevId: 829471173
Change-Id: I2dbc5d9351771817ec260c7ddf87c31e66a9eabe

wasm/codegen/tests/coverage_test.py

@@ -0,0 +1,152 @@
+# Copyright 2025 DeepMind Technologies Limited
+#
+# 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.
+
+"""Tests to ensure that all Mujoco functions and structs are correctly handled.
+
+This file contains tests that verify:
+- All functions defined in Mujoco's introspect module are either bound in the
+  generated bindings.cc file or explicitly excluded in constants.py.
+- All structs defined in Mujoco's introspect module are either bound in the
+  generated bindings.cc file or explicitly skipped in SKIPPED_STRUCTS in
+  constants.py.
+
+These tests help maintain the integrity of the generated WASM bindings by
+ensuring that no functions or structs are accidentally missed or incorrectly
+handled during the code generation process.
+"""
+
+from pathlib import Path
+import re
+
+from absl.testing import absltest
+from introspect import functions as introspect_functions
+from introspect import structs as introspect_structs
+
+from wasm.codegen.generators import common
+from wasm.codegen.generators import constants
+from wasm.codegen.generators import functions
+
+
+def _get_resource_content(file_path: str) -> str:
+  """Reads resource file content using resources.GetResource."""
+  try:
+    with open(file_path, 'r') as f:
+      return f.read()
+  except FileNotFoundError:
+    print(f'Warning: Resource {file_path} not found.')
+    return ''
+  except IOError as e:
+    print(f'Error reading resource {file_path}: {e}')
+    return ''
+
+
+def _get_bound_functions_from_cc() -> set[str]:
+  """Reads bindings.cc and extracts the names of bound functions."""
+  content = _get_resource_content(
+      Path(__file__).parent / 'generated/bindings.cc'
+  )
+  if not content:
+    return set()
+
+  bound_functions = set()
+  # Find all strings within function("...") calls.
+  matches = re.findall(r'function\("([^"]+)"', content)
+  bound_functions.update(matches)
+  return bound_functions
+
+
+def _get_bound_structs_from_cc() -> set[str]:
+  """Reads bindings.cc and extracts the names of bound structs."""
+  content = _get_resource_content(
+      Path(__file__).parent / 'generated/bindings.cc'
+  )
+  if not content:
+    return set()
+
+  bound_structs = set()
+  # Find all strings within class_<...>("...") calls.
+  matches = re.findall(r'class_<[^>]+>\("([^"]+)"\)', content)
+  bound_structs.update(matches)
+  return bound_structs
+
+
+class BindingCoverageTest(absltest.TestCase):
+
+  def test_function_coverage(self):
+    """Asserts that each function is either excluded or bound."""
+    all_functions = set(introspect_functions.FUNCTIONS.keys())
+    excluded_functions = {
+        name
+        for name in all_functions
+        if functions.is_excluded_function_name(name)
+    }
+    bound_functions = _get_bound_functions_from_cc()
+
+    missing_functions = []
+    for func_name in all_functions:
+      if (
+          func_name not in excluded_functions
+          and func_name not in bound_functions
+      ):
+        missing_functions.append(func_name)
+
+    if missing_functions:
+      error_message = (
+          f"""The following functions from functions.py are neither excluded in
+          constants.py nor bound in bindings.cc:
+
+          {", ".join(sorted(missing_functions))}
+
+          Please either add them to a exclusion list in
+          constants.py or create a binding in bindings.cc."""
+      )
+      self.fail(error_message)
+
+  def test_struct_coverage(self):
+    """Asserts that each struct is either not bound or bound in structs.cc."""
+    bound_structs = _get_bound_structs_from_cc()
+    all_structs = {
+        common.uppercase_first_letter(struct_name)
+        for struct_name in introspect_structs.STRUCTS.keys()
+    }
+    skipped_structs = {
+        common.uppercase_first_letter(struct_name)
+        for struct_name in constants.SKIPPED_STRUCTS
+    }
+    missing_structs = []
+    for struct_name in all_structs:
+      if (
+          struct_name not in skipped_structs
+          and struct_name not in bound_structs
+      ):
+        missing_structs.append(struct_name)
+    error_messages = []
+
+    if missing_structs:
+      error_messages.append(
+          f"""The following structs are defined in structs.py but are neither
+            bound in bindings.cc nor listed in SKIPPED_STRUCTS:
+
+            {", ".join(sorted(missing_structs))}
+
+            Please either add them to SKIPPED_STRUCTS or create its binding
+            in bindings.cc."""
+      )
+
+    if error_messages:
+      self.fail('\n\n'.join(error_messages))
+
+
+if __name__ == '__main__':
+  absltest.main()