From 9591210a7ac5289fa00f15d5068383612d3225b9 Mon Sep 17 00:00:00 2001
From: Ruslan Shestopalyuk <rshest@meta.com>
Date: Mon, 30 Dec 2024 12:38:48 -0800
Subject: [PATCH] Add more unit tests for rounding values to pixel grid (#1776)

Summary:
Pull Request resolved: https://github.com/facebook/yoga/pull/1776

# Changelog:
[Internal] -

I was looking into some profiling results and noticed that Yoga has some quirky custom logic when it comes to rounding to the pixel grid, especially for the values that are halfway through.

There are already unit tests in place, but those cases weren't covered, so I am adding these extra corner cases here, to make sure they are covered in case that the actual rounding function may get modified (which it might make sense to, as it's currently can be more expensive than it could have been in some scenarios).

Reviewed By: christophpurrer

Differential Revision: D67712673

fbshipit-source-id: da1b7339a8939ced8d91f15441bc7d1f8af768c8
---
 tests/YGRoundingFunctionTest.cpp | 40 ++++++++++++++++++++++++++++++++
 1 file changed, 40 insertions(+)

diff --git a/tests/YGRoundingFunctionTest.cpp b/tests/YGRoundingFunctionTest.cpp
index b49d0644..55b5e86d 100644
--- a/tests/YGRoundingFunctionTest.cpp
+++ b/tests/YGRoundingFunctionTest.cpp
@@ -8,6 +8,8 @@
 #include <gtest/gtest.h>
 #include <yoga/Yoga.h>
 
+#include <cmath>
+
 TEST(YogaTest, rounding_value) {
   // Test that whole numbers are rounded to whole despite ceil/floor flags
   ASSERT_FLOAT_EQ(6.0, YGRoundValueToPixelGrid(6.000001, 2.0, false, false));
@@ -39,6 +41,44 @@ TEST(YogaTest, rounding_value) {
   ASSERT_FLOAT_EQ(-6.0, YGRoundValueToPixelGrid(-5.99, 2.0, false, false));
   ASSERT_FLOAT_EQ(-5.5, YGRoundValueToPixelGrid(-5.99, 2.0, true, false));
   ASSERT_FLOAT_EQ(-6.0, YGRoundValueToPixelGrid(-5.99, 2.0, false, true));
+
+  // Rounding up/down halfway values is as expected for both positive and
+  // negative numbers
+  ASSERT_FLOAT_EQ(-3, YGRoundValueToPixelGrid(-3.5, 1.0, false, false));
+  ASSERT_FLOAT_EQ(-3, YGRoundValueToPixelGrid(-3.4, 1.0, false, false));
+  ASSERT_FLOAT_EQ(-4, YGRoundValueToPixelGrid(-3.6, 1.0, false, false));
+  ASSERT_FLOAT_EQ(-3, YGRoundValueToPixelGrid(-3.499999, 1.0, false, false));
+  ASSERT_FLOAT_EQ(-3, YGRoundValueToPixelGrid(-3.500001, 1.0, false, false));
+  ASSERT_FLOAT_EQ(-4, YGRoundValueToPixelGrid(-3.5001, 1.0, false, false));
+
+  ASSERT_FLOAT_EQ(-3, YGRoundValueToPixelGrid(-3.5, 1.0, true, false));
+  ASSERT_FLOAT_EQ(-3, YGRoundValueToPixelGrid(-3.4, 1.0, true, false));
+  ASSERT_FLOAT_EQ(-3, YGRoundValueToPixelGrid(-3.6, 1.0, true, false));
+  ASSERT_FLOAT_EQ(-3, YGRoundValueToPixelGrid(-3.499999, 1.0, true, false));
+  ASSERT_FLOAT_EQ(-3, YGRoundValueToPixelGrid(-3.500001, 1.0, true, false));
+  ASSERT_FLOAT_EQ(-3, YGRoundValueToPixelGrid(-3.5001, 1.0, true, false));
+  ASSERT_FLOAT_EQ(-3, YGRoundValueToPixelGrid(-3.00001, 1.0, true, false));
+  ASSERT_FLOAT_EQ(-3, YGRoundValueToPixelGrid(-3, 1.0, true, false));
+
+  ASSERT_FLOAT_EQ(-4, YGRoundValueToPixelGrid(-3.5, 1.0, false, true));
+  ASSERT_FLOAT_EQ(-4, YGRoundValueToPixelGrid(-3.4, 1.0, false, true));
+  ASSERT_FLOAT_EQ(-4, YGRoundValueToPixelGrid(-3.6, 1.0, false, true));
+  ASSERT_FLOAT_EQ(-4, YGRoundValueToPixelGrid(-3.499999, 1.0, false, true));
+  ASSERT_FLOAT_EQ(-4, YGRoundValueToPixelGrid(-3.500001, 1.0, false, true));
+  ASSERT_FLOAT_EQ(-4, YGRoundValueToPixelGrid(-3.5001, 1.0, false, true));
+  ASSERT_FLOAT_EQ(-3, YGRoundValueToPixelGrid(-3.00001, 1.0, false, true));
+  ASSERT_FLOAT_EQ(-3, YGRoundValueToPixelGrid(-3, 1.0, false, true));
+
+  // NAN is treated as expected:
+  ASSERT_TRUE(std::isnan(YGRoundValueToPixelGrid(
+      std::numeric_limits<double>::quiet_NaN(), 1.5, false, false)));
+  ASSERT_TRUE(std::isnan(YGRoundValueToPixelGrid(
+      1.5, std::numeric_limits<double>::quiet_NaN(), false, false)));
+  ASSERT_TRUE(std::isnan(YGRoundValueToPixelGrid(
+      std::numeric_limits<double>::quiet_NaN(),
+      std::numeric_limits<double>::quiet_NaN(),
+      false,
+      false)));
 }
 
 static YGSize measureText(