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.h

@@ -7,9 +7,10 @@
 
 #pragma once
 
+#include <yoga/YGNode.h>
 #include <yoga/event/event.h>
-
 #include <functional>
+#include <string_view>
 
 namespace facebook::yoga::test {
 
@@ -24,4 +25,19 @@ struct ScopedEventSubscription {
   ~ScopedEventSubscription();
 };
 
+YGSize IntrinsicSizeMeasure(
+    YGNodeConstRef node,
+    float width,
+    YGMeasureMode widthMode,
+    float height,
+    YGMeasureMode heightMode);
+
+float longestWordWidth(std::string_view text, float widthPerChar);
+
+float calculateHeight(
+    std::string_view text,
+    float measuredWidth,
+    float widthPerChar,
+    float heightPerChar);
+
 } // namespace facebook::yoga::test