Add tests for SetMeasureFunction

Summary: Add tests for checking C side asserts in managed

Reviewed By: emilsjolander

Differential Revision: D4154869

fbshipit-source-id: 5203db27eff963d46f188de448f607a24ed63fab

csharp/tests/Facebook.CSSLayout/CSSNodeTest.cs

@@ -161,6 +161,30 @@ namespace Facebook.CSSLayout
             Assert.AreEqual(150, (int)node.LayoutHeight);
         }
 
+        [Test]
+        [ExpectedException("System.InvalidOperationException")]
+        public void TestChildWithMeasureFunc()
+        {
+            CSSNode node = new CSSNode();
+            node.SetMeasureFunction((_, width, widthMode, height, heightMode) => {
+                return MeasureOutput.Make(100, 150);
+            });
+            CSSNode child = new CSSNode();
+            node.Insert(0, child);
+        }
+
+        [Test]
+        [ExpectedException("System.InvalidOperationException")]
+        public void TestMeasureFuncWithChild()
+        {
+            CSSNode node = new CSSNode();
+            CSSNode child = new CSSNode();
+            node.Insert(0, child);
+            node.SetMeasureFunction((_, width, widthMode, height, heightMode) => {
+                return MeasureOutput.Make(100, 150);
+            });
+        }
+
         [Test]
         public void TestPrint()
         {