1 files changed, 304 insertions, 0 deletions
diff --git a/Xamarin.Forms.Core.UnitTests/NavigationModelTests.cs b/Xamarin.Forms.Core.UnitTests/NavigationModelTests.cs
new file mode 100644
index 00000000..ec3aaf5f
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+++ b/Xamarin.Forms.Core.UnitTests/NavigationModelTests.cs
@@ -0,0 +1,304 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Text;
+using System.Threading.Tasks;
+using NUnit.Framework;
+
+namespace Xamarin.Forms.Core.UnitTests
+{
+	[TestFixture]
+	public class NavigationModelTests : BaseTestFixture
+	{
+		[Test]
+		public void CurrentNullWhenEmpty ()
+		{
+			var navModel = new NavigationModel ();
+			Assert.Null (navModel.CurrentPage);
+		}
+
+		[Test]
+		public void CurrentGivesLastViewWithoutModal ()
+		{
+			var navModel = new NavigationModel ();
+
+			var page1 = new ContentPage ();
+			var page2 = new ContentPage ();
+
+			navModel.Push (page1, null);
+			navModel.Push (page2, page1);
+
+			Assert.AreEqual (page2, navModel.CurrentPage);
+		}
+
+		[Test]
+		public void CurrentGivesLastViewWithModal()
+		{
+			var navModel = new NavigationModel ();
+
+			var page1 = new ContentPage ();
+			var page2 = new ContentPage ();
+
+			var modal1 = new ContentPage ();
+			var modal2 = new ContentPage ();
+
+			navModel.Push (page1, null);
+			navModel.Push (page2, page1);
+
+			navModel.PushModal (modal1);
+			navModel.Push (modal2, modal1);
+
+			Assert.AreEqual (modal2, navModel.CurrentPage);
+		}
+
+		[Test]
+		public void Roots ()
+		{
+			var navModel = new NavigationModel ();
+
+			var page1 = new ContentPage ();
+			var page2 = new ContentPage ();
+
+			var modal1 = new ContentPage ();
+			var modal2 = new ContentPage ();
+
+			navModel.Push (page1, null);
+			navModel.Push (page2, page1);
+
+			navModel.PushModal (modal1);
+			navModel.Push (modal2, modal1);
+
+			Assert.True (navModel.Roots.SequenceEqual (new[] {page1, modal1}));
+		}
+
+		[Test]
+		public void PushFirstItem ()
+		{
+			var navModel = new NavigationModel ();
+
+			var page1 = new ContentPage ();
+			navModel.Push (page1, null);
+
+			Assert.AreEqual (page1, navModel.CurrentPage);
+			Assert.AreEqual (page1, navModel.Roots.First ());
+		}
+
+		[Test]
+		public void ThrowsWhenPushingWithoutAncestor ()
+		{
+			var navModel = new NavigationModel ();
+
+			var page1 = new ContentPage ();
+			var page2 = new ContentPage ();
+
+			navModel.Push (page1, null);
+			Assert.Throws<InvalidNavigationException> (() => navModel.Push (page2, null));
+		}
+
+		[Test]
+		public void PushFromNonRootAncestor ()
+		{
+			var navModel = new NavigationModel ();
+
+			var page1 = new ContentPage ();
+			var page2 = new ContentPage ();
+			var page3 = new ContentPage ();
+
+			page2.Parent = page1;
+			page3.Parent = page2;
+
+			navModel.Push (page1, null);
+			navModel.Push (page2, page1);
+			navModel.Push (page3, page2);
+
+			Assert.AreEqual (page3, navModel.CurrentPage);
+		}
+
+		[Test]
+		public void ThrowsWhenPushFromInvalidAncestor ()
+		{
+			var navModel = new NavigationModel ();
+
+			var page1 = new ContentPage ();
+			var page2 = new ContentPage ();
+
+			Assert.Throws<InvalidNavigationException> (() => navModel.Push (page2, page1));
+		}
+
+		[Test]
+		public void Pop ()
+		{
+			var navModel = new NavigationModel ();
+
+			var page1 = new ContentPage ();
+			var page2 = new ContentPage ();
+
+			navModel.Push (page1, null);
+			navModel.Push (page2, page1);
+
+			navModel.Pop (page1);
+
+			Assert.AreEqual (page1, navModel.CurrentPage);
+		}
+
+		[Test]
+		public void ThrowsPoppingRootItem ()
+		{
+			var navModel = new NavigationModel ();
+
+			var page1 = new ContentPage ();
+
+			navModel.Push (page1, null);
+
+			Assert.Throws<InvalidNavigationException> (() => navModel.Pop (page1));
+		}
+
+		[Test]
+		public void ThrowsPoppingRootOfModal ()
+		{
+			var navModel = new NavigationModel ();
+
+			var page1 = new ContentPage ();
+			var page2 = new ContentPage ();
+
+			var modal1 = new ContentPage ();
+
+			navModel.Push (page1, null);
+			navModel.Push (page2, page1);
+
+			navModel.PushModal (modal1);
+			Assert.Throws<InvalidNavigationException> (() => navModel.Pop (modal1));
+		}
+
+		[Test]
+		public void ThrowsPoppingWithInvalidAncestor ()
+		{
+			var navModel = new NavigationModel ();
+
+			var page1 = new ContentPage ();
+
+			navModel.Push (page1, null);
+
+			Assert.Throws<InvalidNavigationException> (() => navModel.Pop (new ContentPage ()));
+		}
+
+		[Test]
+		public void PopToRoot ()
+		{
+			var navModel = new NavigationModel ();
+
+			var page1 = new ContentPage ();
+			var page2 = new ContentPage ();
+			var page3 = new ContentPage ();
+
+			page2.Parent = page1;
+			page3.Parent = page2;
+
+			navModel.Push (page1, null);
+			navModel.Push (page2, page1);
+			navModel.Push (page3, page2);
+
+			navModel.PopToRoot (page2);
+
+			Assert.AreEqual (page1, navModel.CurrentPage);
+		}
+
+		[Test]
+		public void ThrowsWhenPopToRootOnRoot ()
+		{
+			var navModel = new NavigationModel ();
+
+			var page1 = new ContentPage ();
+
+			navModel.Push (page1, null);
+			Assert.Throws<InvalidNavigationException> (() => navModel.PopToRoot (page1));
+		}
+
+		[Test]
+		public void ThrowsWhenPopToRootWithInvalidAncestor()
+		{
+			var navModel = new NavigationModel ();
+
+			var page1 = new ContentPage ();
+			var page2 = new ContentPage ();
+
+			navModel.Push (page1, null);
+			navModel.Push (page2, page1);
+
+			Assert.Throws<InvalidNavigationException> (() => navModel.PopToRoot (new ContentPage ()));
+		}
+
+		[Test]
+		public void PopModal ()
+		{
+			var navModel = new NavigationModel ();
+
+			var child1 = new ContentPage ();
+			var modal1 = new ContentPage ();
+
+			navModel.Push (child1, null);
+			navModel.PushModal (modal1);
+
+			navModel.PopModal ();
+
+			Assert.AreEqual (child1, navModel.CurrentPage);
+			Assert.AreEqual (1, navModel.Roots.Count ());
+		}
+
+		[Test]
+		public void ReturnsCorrectModal ()
+		{
+			var navModel = new NavigationModel ();
+
+			var child1 = new ContentPage ();
+			var modal1 = new ContentPage ();
+			var modal2 = new ContentPage ();
+
+			navModel.Push (child1, null);
+			navModel.PushModal (modal1);
+			navModel.PushModal (modal2);
+
+			Assert.AreEqual (modal2, navModel.PopModal ());
+		}
+
+		[Test]
+		public void PopTopPageWithoutModals ()
+		{
+			var navModel = new NavigationModel ();
+
+			var page1 = new ContentPage ();
+			var page2 = new ContentPage ();
+
+			navModel.Push (page1, null);
+			navModel.Push (page2, page1);
+
+			Assert.AreEqual (page2, navModel.PopTopPage ());
+		}
+
+		[Test]
+		public void PopTopPageWithSinglePage ()
+		{
+			var navModel = new NavigationModel ();
+
+			var page1 = new ContentPage ();
+
+			navModel.Push (page1, null);
+
+			Assert.Null (navModel.PopTopPage ());
+		}
+
+		[Test]
+		public void PopTopPageWithModal ()
+		{
+			var navModel = new NavigationModel ();
+
+			var page1 = new ContentPage ();
+			var modal1 = new ContentPage ();
+
+			navModel.Push (page1, null);
+			navModel.PushModal (modal1);
+
+			Assert.AreEqual (modal1, navModel.PopTopPage ());
+		}
+	}
+}