Let gentest properly create *Auto methods for sizes (#1719)

Summary:
Pull Request resolved: https://github.com/facebook/yoga/pull/1719

Right now there is no way to test fixtures with `auto` widths, heights, or flex basis - even though we expose those functions. I updated gentest to generate those functions. Notably, position and margin (the other auto-able props) already account for this.

 I also created `YGAutoTest.html` to test this. Not really testing the capabilities of `auto` here, just if we can create a test about it.

Reviewed By: NickGerleman

Differential Revision: D64125522

fbshipit-source-id: 291ec82003cf53f99c21943142a63e2ef30402a5

gentest/gentest-java.js

@@ -21,6 +21,23 @@ function toMethodName(value) {
   return '';
 }
 
+function keywordMethod(methodPrefix, nodeName, value) {
+  const methodSuffix = toMethodName(value);
+  if (methodSuffix == 'Auto') {
+    return nodeName + '.' + methodPrefix + methodSuffix + '();';
+  } else {
+    return (
+      nodeName +
+      '.' +
+      methodPrefix +
+      methodSuffix +
+      '(' +
+      toValueJava(value) +
+      'f);'
+    );
+  }
+}
+
 const JavaEmitter = function () {
   Emitter.call(this, 'java', '  ');
 };
@@ -273,14 +290,7 @@ JavaEmitter.prototype = Object.create(Emitter.prototype, {
 
   YGNodeStyleSetFlexBasis: {
     value: function (nodeName, value) {
-      this.push(
-        nodeName +
-          '.setFlexBasis' +
-          toMethodName(value) +
-          '(' +
-          toValueJava(value) +
-          'f);',
-      );
+      this.push(keywordMethod('setFlexBasis', nodeName, value));
     },
   },
 
@@ -308,19 +318,6 @@ JavaEmitter.prototype = Object.create(Emitter.prototype, {
     },
   },
 
-  YGNodeStyleSetHeight: {
-    value: function (nodeName, value) {
-      this.push(
-        nodeName +
-          '.setHeight' +
-          toMethodName(value) +
-          '(' +
-          toValueJava(value) +
-          'f);',
-      );
-    },
-  },
-
   YGNodeStyleSetJustifyContent: {
     value: function (nodeName, value) {
       this.push(nodeName + '.setJustifyContent(' + toValueJava(value) + ');');
@@ -348,6 +345,18 @@ JavaEmitter.prototype = Object.create(Emitter.prototype, {
     },
   },
 
+  YGNodeStyleSetHeight: {
+    value: function (nodeName, value) {
+      this.push(keywordMethod('setHeight', nodeName, value));
+    },
+  },
+
+  YGNodeStyleSetWidth: {
+    value: function (nodeName, value) {
+      this.push(keywordMethod('setWidth', nodeName, value));
+    },
+  },
+
   YGNodeStyleSetMaxHeight: {
     value: function (nodeName, value) {
       this.push(
@@ -448,19 +457,6 @@ JavaEmitter.prototype = Object.create(Emitter.prototype, {
     },
   },
 
-  YGNodeStyleSetWidth: {
-    value: function (nodeName, value) {
-      this.push(
-        nodeName +
-          '.setWidth' +
-          toMethodName(value) +
-          '(' +
-          toValueJava(value) +
-          'f);',
-      );
-    },
-  },
-
   YGNodeStyleSetGap: {
     value: function (nodeName, gap, value) {
       this.push(