Add Button text ctor

.vscode/tasks.json

@@ -11,6 +11,14 @@
             ],
             "isBuildCommand": true,
             "problemMatcher": "$msCompile"
+        },
+        {
+            "taskName": "test",
+            "args": [
+                "${workspaceRoot}/Tests/Tests.csproj"
+            ],
+            "isTestCommand": true,
+            "problemMatcher": "$msCompile"
         }
     ]
 }

Ooui/Button.cs

@@ -15,5 +15,14 @@ namespace Ooui
             get => val;
             set => SetProperty (ref val, value, "value");
         }
+
+        public Button ()
+        {
+        }
+
+        public Button (string text)
+        {
+            Text = text;
+        }
     }
 }

Ooui/TextNode.cs

@@ -11,7 +11,7 @@ namespace Ooui
         }
 
         public TextNode ()
-        {            
+        {
         }
 
         public TextNode (string text)

Tests/ButtonTests.cs

@@ -14,5 +14,12 @@ namespace Tests
             var b = new Button ();
             Assert.AreEqual ("", b.Text);
         }
+
+        [TestMethod]
+        public void TextCtor ()
+        {
+            var b = new Button ("Hello World!");
+            Assert.AreEqual ("Hello World!", b.Text);
+        }
     }
 }