Add unit tests for model parsing

Source/Model/Model.cs

@@ -647,7 +647,7 @@ public override string ToString()
 
     #region factory methods
 
-    Element ConstructElement(string name)
+    public Element ConstructElement(string name)
     {
       if (name.ToLower() == "true")
       {

Source/UnitTests/CoreTests/Model.cs

@@ -0,0 +1,49 @@
+using Microsoft.Boogie;
+using NUnit.Framework;
+
+namespace ModelTests
+{
+  [TestFixture()]
+  public class ModelTests
+  {
+    [Test]
+    public void ParseRealModelElements()
+    {
+      var m = new Model();
+      var e1 = m.ConstructElement("1e2");
+      Assert.AreEqual(e1.Kind, Model.ElementKind.Real);
+      Assert.AreEqual(e1.ToString(), "1e2");
+      var e2 = m.ConstructElement("-3e5");
+      Assert.AreEqual(e2.Kind, Model.ElementKind.Real);
+      Assert.AreEqual(e2.ToString(), "-3e5");
+      var e3 = m.ConstructElement("1.2e3");
+      Assert.AreEqual(e3.Kind, Model.ElementKind.Real);
+      Assert.AreEqual(e3.ToString(), "1.2e3");
+      var e4 = m.ConstructElement("-3.1e6");
+      Assert.AreEqual(e4.Kind, Model.ElementKind.Real);
+      Assert.AreEqual(e4.ToString(), "-3.1e6");
+    }
+
+    [Test]
+    public void ParseBoolModelElements()
+    {
+      var m = new Model();
+      var e1 = m.ConstructElement("true");
+      Assert.AreEqual(e1, m.True);
+      var e2 = m.ConstructElement("false");
+      Assert.AreEqual(e2, m.False);
+    }
+
+    [Test]
+    public void ParseIntModelElements()
+    {
+      var m = new Model();
+      var e1 = m.ConstructElement("3289");
+      Assert.AreEqual(e1.Kind, Model.ElementKind.Integer);
+      Assert.AreEqual(e1.ToString(), "3289");
+      var e2 = m.ConstructElement("-12389");
+      Assert.AreEqual(e2.Kind, Model.ElementKind.Integer);
+      Assert.AreEqual(e2.ToString(), "-12389");
+    }
+  }
+}