1 files changed, 51 insertions, 0 deletions
diff --git a/third_party/jpeg-xl/lib/jxl/enc_photon_noise_test.cc b/third_party/jpeg-xl/lib/jxl/enc_photon_noise_test.cc
new file mode 100644
index 0000000000..be11b465ad
--- /dev/null
+++ b/third_party/jpeg-xl/lib/jxl/enc_photon_noise_test.cc
@@ -0,0 +1,51 @@
+// Copyright (c) the JPEG XL Project Authors. All rights reserved.
+//
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+#include "lib/jxl/enc_photon_noise.h"
+
+#include "lib/jxl/test_utils.h"
+#include "lib/jxl/testing.h"
+
+namespace jxl {
+namespace {
+
+using ::testing::FloatNear;
+using ::testing::Pointwise;
+
+MATCHER(AreApproximatelyEqual, "") {
+  constexpr float kTolerance = 1e-6;
+  const float actual = std::get<0>(arg);
+  const float expected = std::get<1>(arg);
+  return testing::ExplainMatchResult(FloatNear(expected, kTolerance), actual,
+                                     result_listener);
+}
+
+TEST(EncPhotonNoiseTest, LUTs) {
+  EXPECT_THAT(
+      SimulatePhotonNoise(/*xsize=*/6000, /*ysize=*/4000, /*iso=*/100).lut,
+      Pointwise(AreApproximatelyEqual(),
+                {0.00259652, 0.0139648, 0.00681551, 0.00632582, 0.00694917,
+                 0.00803922, 0.00934574, 0.0107607}));
+  EXPECT_THAT(
+      SimulatePhotonNoise(/*xsize=*/6000, /*ysize=*/4000, /*iso=*/800).lut,
+      Pointwise(AreApproximatelyEqual(),
+                {0.02077220, 0.0420923, 0.01820690, 0.01439020, 0.01293670,
+                 0.01254030, 0.01277390, 0.0134161}));
+  EXPECT_THAT(
+      SimulatePhotonNoise(/*xsize=*/6000, /*ysize=*/4000, /*iso=*/6400).lut,
+      Pointwise(AreApproximatelyEqual(),
+                {0.1661770, 0.1691120, 0.05309080, 0.03963960, 0.03357410,
+                 0.03001650, 0.02776740, 0.0263478}));
+
+  // Lower when measured on a per-pixel basis as there are fewer of them.
+  EXPECT_THAT(
+      SimulatePhotonNoise(/*xsize=*/4000, /*ysize=*/3000, /*iso=*/6400).lut,
+      Pointwise(AreApproximatelyEqual(),
+                {0.0830886, 0.1008720, 0.0367748, 0.0280305, 0.0240236,
+                 0.0218040, 0.0205771, 0.0200058}));
+}
+
+}  // namespace
+}  // namespace jxl