Initial open sourcing of MuJoCo.

PiperOrigin-RevId: 450374687
Change-Id: Ie3225a46ce095fc28ae8e63c326a640261f562bb

test/fixture.h

@@ -0,0 +1,60 @@
+// Copyright 2021 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.
+
+#ifndef MUJOCO_TEST_FIXTURE_H_
+#define MUJOCO_TEST_FIXTURE_H_
+
+#include <gtest/gtest.h>
+#include <absl/strings/string_view.h>
+#include <mujoco/mjmodel.h>
+
+namespace mujoco {
+
+// Installs and uninstalls error callbacks on MuJoCo that fail the currently
+// running test if triggered. Prefer the use of MujocoTest, unless using a
+// test fixture is not possible.
+class MujocoErrorTestGuard {
+ public:
+  // Sets up error and warning callbacks on MuJoCo that will fail the test if
+  // triggered.
+  MujocoErrorTestGuard();
+
+  // Clears up the callbacks from the constructor.
+  ~MujocoErrorTestGuard();
+};
+
+// A test fixture which simplifies writing tests for the MuJoCo C API.
+// By default, any MuJoCo operation which triggers a warning or error will
+// trigger a test failure.
+class MujocoTest : public ::testing::Test {
+ private:
+  MujocoErrorTestGuard error_guard;
+};
+
+// Returns a path to a data file, under the mujoco/test directory.
+const std::string GetTestDataFilePath(absl::string_view path);
+
+// Returns a path to a data file, under the mujoco/model directory.
+const std::string GetModelPath(absl::string_view path);
+
+// Returns a newly-allocated mjModel, loaded from the contents of xml.
+// On failure returns nullptr and populates the error array if present.
+mjModel* LoadModelFromString(absl::string_view xml, char* error = nullptr,
+                             int error_size = 0);
+
+// Returns a string loaded from first saving the model given an input.
+const std::string SaveAndReadXml(const mjModel* model);
+
+}  // namespace mujoco
+#endif  // MUJOCO_TEST_FIXTURE_H_