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diff --git a/src/3rdparty/resonance-audio/resonance_audio/geometrical_acoustics/acoustic_source_test.cc b/src/3rdparty/resonance-audio/resonance_audio/geometrical_acoustics/acoustic_source_test.cc
new file mode 100644
index 000000000..aa05a8112
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+++ b/src/3rdparty/resonance-audio/resonance_audio/geometrical_acoustics/acoustic_source_test.cc
@@ -0,0 +1,136 @@
+/*
+Copyright 2018 Google Inc. All Rights Reserved.
+
+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.
+*/
+
+#include "geometrical_acoustics/acoustic_source.h"
+
+#include <cmath>
+#include <random>
+#include <vector>
+
+#include "third_party/googletest/googletest/include/gtest/gtest.h"
+#include "base/constants_and_types.h"
+#include "geometrical_acoustics/test_util.h"
+
+namespace vraudio {
+
+namespace {
+
+TEST(AcousticSource, GeneratedRayNonDirectionalDataTest) {
+  std::default_random_engine engine(0);
+  std::uniform_real_distribution<float> distribution(0.0f, 1.0f);
+  const std::array<float, kNumReverbOctaveBands> energies{
+      {1.0f, 2.0f, 3.0f, 4.0f, 5.0f, 6.0f, 7.0f, 8.0f, 9.0f}};
+  AcousticSource source({0.1f, 0.2f, 0.3f}, energies, [&engine, &distribution] {
+    return distribution(engine);
+  });
+  AcousticRay ray = source.GenerateRay();
+
+  EXPECT_EQ(ray.type(), AcousticRay::RayType::kSpecular);
+  for (size_t i = 0; i < kNumReverbOctaveBands; ++i) {
+    EXPECT_FLOAT_EQ(ray.energies().at(i), energies.at(i));
+  }
+  EXPECT_FLOAT_EQ(ray.t_near(), 0.0f);
+  const float expected_origin[3] = {0.1f, 0.2f, 0.3f};
+  ExpectFloat3Close(ray.origin(), expected_origin);
+}
+
+TEST(AcousticSource, GeneratedRayDirectionDistributionTest) {
+  std::default_random_engine engine(0);
+  std::uniform_real_distribution<float> distribution(0.0f, 1.0f);
+  const std::array<float, kNumReverbOctaveBands> energies{
+      {1.0f, 1.0f, 1.0f, 1.0f, 1.0f, 1.0f, 1.0f, 1.0f, 1.0f}};
+  AcousticSource source({0.0f, 0.0f, 0.0f}, energies, [&engine, &distribution] {
+    return distribution(engine);
+  });
+
+  // Check that the direction vectors on generated rays are all normalized,
+  // i.e., of unit lengths.
+  for (size_t i = 0; i < 1000; ++i) {
+    AcousticRay ray = source.GenerateRay();
+    const float direction_squared_norm =
+        ray.direction()[0] * ray.direction()[0] +
+        ray.direction()[1] * ray.direction()[1] +
+        ray.direction()[2] * ray.direction()[2];
+    EXPECT_FLOAT_EQ(direction_squared_norm, 1.0f);
+  }
+
+  // For a ray whose direction is uniformly distributed over a sphere:
+  // - The PDF of theta is sin(theta), and the CDF is (1 - cos(theta)) / 2.
+  // - The PDF of phi is 1 / 2 pi, and the CDF is 0.5 + phi / 2 pi.
+  ValidateDistribution(100000, 100, [&source]() {
+    AcousticRay ray = source.GenerateRay();
+    const float cos_theta = ray.direction()[2];
+    return 0.5f * (1.0f - cos_theta);
+  });
+
+  ValidateDistribution(100000, 100, [&source]() {
+    AcousticRay ray = source.GenerateRay();
+    const float* direction = ray.direction();
+    const float phi = std::atan2(direction[1], direction[0]);
+    return 0.5f + phi / 2.0f / static_cast<float>(M_PI);
+  });
+}
+
+// Similar to GeneratedRayDirectionDistributionTest, but tests on the whole
+// set of rays generated by AcousticSource::GenerateStratifiedRays() that they
+// are uniformly distributed.
+TEST(AcousticSource, GeneratedStratifiedRaysDirectionDistributionTest) {
+  std::default_random_engine engine(0);
+  std::uniform_real_distribution<float> distribution(0.0f, 1.0f);
+  const std::array<float, kNumReverbOctaveBands> energies{
+      {1.0f, 1.0f, 1.0f, 1.0f, 1.0f, 1.0f, 1.0f, 1.0f, 1.0f}};
+  AcousticSource source({0.0f, 0.0f, 0.0f}, energies, [&engine, &distribution] {
+    return distribution(engine);
+  });
+
+  // Check that the direction vectors on generated rays are all normalized,
+  // i.e., of unit lengths.
+  const size_t num_rays = 10000;
+  const size_t sqrt_num_rays = 100;
+  std::vector<AcousticRay> rays =
+      source.GenerateStratifiedRays(num_rays, sqrt_num_rays);
+  for (const AcousticRay& ray : rays) {
+    const float direction_squared_norm =
+        ray.direction()[0] * ray.direction()[0] +
+        ray.direction()[1] * ray.direction()[1] +
+        ray.direction()[2] * ray.direction()[2];
+    EXPECT_FLOAT_EQ(direction_squared_norm, 1.0f);
+  }
+
+  // For a ray whose direction is uniformly distributed over a sphere:
+  // - The PDF of theta is sin(theta), and the CDF is (1 - cos(theta)) / 2.
+  // - The PDF of phi is 1 / 2 pi, and the CDF is 0.5 + phi / 2 pi.
+  size_t ray_index = 0;
+  ValidateDistribution(num_rays, 100, [&rays, &ray_index]() {
+    const AcousticRay& ray = rays[ray_index];
+    ++ray_index;
+    const float cos_theta = ray.direction()[2];
+    return 0.5f * (1.0f - cos_theta);
+  });
+
+  ray_index = 0;
+  ValidateDistribution(num_rays, 100, [&rays, &ray_index]() {
+    const AcousticRay& ray = rays[ray_index];
+    ++ray_index;
+    const float* direction = ray.direction();
+    const float phi = std::atan2(direction[1], direction[0]);
+    return 0.5f + phi / kTwoPi;
+  });
+}
+
+}  // namespace
+
+}  // namespace vraudio