Add test support for intrinsic sized nodes (#1671)

Summary:
Pull Request resolved: https://github.com/facebook/yoga/pull/1671

This diff adds support for intrinsic sizing in generated tests. This is done by importing a testing font called "Ahem" which, as used, has an exact width and height of 10px for each character. Support has been added for C++, Java, and Javascript generated tests.

Reviewed By: NickGerleman

Differential Revision: D58307002

fbshipit-source-id: e1dcc1e03310d35a32e0c70f71994880d8f7de55

tests/util/TestUtil.cpp

@@ -7,8 +7,14 @@
 
 #include "TestUtil.h"
 
+#include <yoga/YGEnums.h>
+#include <yoga/YGNode.h>
 #include <yoga/event/event.h>
 #include <yoga/node/Node.h>
+#include <iostream>
+#include <sstream>
+#include <string>
+#include <string_view>
 
 namespace facebook::yoga::test {
 
@@ -58,4 +64,95 @@ ScopedEventSubscription::~ScopedEventSubscription() {
   Event::reset();
 }
 
+YGSize IntrinsicSizeMeasure(
+    YGNodeConstRef node,
+    float width,
+    YGMeasureMode widthMode,
+    float height,
+    YGMeasureMode heightMode) {
+  std::string_view innerText((char*)YGNodeGetContext(node));
+  float heightPerChar = 10;
+  float widthPerChar = 10;
+  float measuredWidth;
+  float measuredHeight;
+
+  if (widthMode == YGMeasureModeExactly) {
+    measuredWidth = width;
+  } else if (widthMode == YGMeasureModeAtMost) {
+    measuredWidth = std::min((float)innerText.size() * widthPerChar, width);
+  } else {
+    measuredWidth = (float)innerText.size() * widthPerChar;
+  }
+
+  if (heightMode == YGMeasureModeExactly) {
+    measuredHeight = height;
+  } else if (heightMode == YGMeasureModeAtMost) {
+    measuredHeight = std::min(
+        calculateHeight(
+            innerText,
+            std::max(longestWordWidth(innerText, widthPerChar), measuredWidth),
+            widthPerChar,
+            heightPerChar),
+        height);
+  } else {
+    measuredHeight = calculateHeight(
+        innerText,
+        std::max(longestWordWidth(innerText, widthPerChar), measuredWidth),
+        widthPerChar,
+        heightPerChar);
+  }
+
+  return YGSize{measuredWidth, measuredHeight};
+}
+
+float longestWordWidth(std::string_view text, float widthPerChar) {
+  int maxLength = 0;
+  int currentLength = 0;
+  for (auto c : text) {
+    if (c == ' ') {
+      maxLength = std::max(currentLength, maxLength);
+      currentLength = 0;
+    } else {
+      currentLength++;
+    }
+  }
+  return (float)std::max(currentLength, maxLength) * widthPerChar;
+}
+
+float calculateHeight(
+    std::string_view text,
+    float measuredWidth,
+    float widthPerChar,
+    float heightPerChar) {
+  if ((float)text.size() * widthPerChar <= measuredWidth) {
+    return heightPerChar;
+  }
+
+  std::vector<std::string> words;
+  std::istringstream iss((std::string)text);
+  std::string currentWord;
+  while (getline(iss, currentWord, ' ')) {
+    words.push_back(currentWord);
+  }
+
+  float lines = 1;
+  float currentLineLength = 0;
+  for (const std::string& word : words) {
+    float wordWidth = (float)word.length() * widthPerChar;
+    if (wordWidth > measuredWidth) {
+      if (currentLineLength > 0) {
+        lines++;
+      }
+      lines++;
+      currentLineLength = 0;
+    } else if (currentLineLength + wordWidth <= measuredWidth) {
+      currentLineLength += wordWidth + widthPerChar;
+    } else {
+      lines++;
+      currentLineLength = wordWidth + widthPerChar;
+    }
+  }
+  return (currentLineLength == 0 ? lines - 1 : lines) * heightPerChar;
+}
+
 } // namespace facebook::yoga::test