Changed the Python console window command line history so it behaves the same as ipy. Previously after reaching the start/end of the command line history the start/end command line would be shown again when moving the other way through the history.

git-svn-id: svn://svn.sharpdevelop.net/sharpdevelop/branches/3.0@3632 1ccf3a8d-04fe-1044-b7c0-cef0b8235c61

src/AddIns/BackendBindings/Python/PythonBinding/Project/Src/CommandLineHistory.cs

@@ -16,7 +16,7 @@ namespace ICSharpCode.PythonBinding
 	public class CommandLineHistory
 	{
 		List<string> lines = new List<string>();
-		int position = -1;
+		int position;
 		
 		public CommandLineHistory()
 		{
@@ -55,20 +55,26 @@ namespace ICSharpCode.PythonBinding
 		/// <summary>
 		/// Moves to the next command line.
 		/// </summary>
+		/// <returns>False if the current position is at the end of the command line history.</returns>
 		public bool MoveNext()
 		{
-			if (position < lines.Count) {
+			int nextPosition = position + 1;
+			if (nextPosition < lines.Count) {
 				++position;
 			}
-			return position < lines.Count;
+			return nextPosition < lines.Count;
 		}
 		
 		/// <summary>
 		/// Moves to the previous command line.
 		/// </summary>
+		/// <returns>False if the current position is at the start of the command line history.</returns>
 		public bool MovePrevious()
 		{
 			if (position >= 0) {
+				if (position == 0) {
+					return false;
+				}
 				--position;
 			}
 			return position >= 0;

src/AddIns/BackendBindings/Python/PythonBinding/Test/Console/CommandLineHistoryTestFixture.cs

@@ -64,5 +64,19 @@ namespace PythonBinding.Tests.Console
 			history.MovePrevious();
 			Assert.AreEqual("c", history.Current);
 		}
+		
+		/// <summary>
+		/// After trying to move beyond the end of the list moving previous should not show the last
+		/// item again.
+		/// </summary>
+		[Test]
+		public void MovePreviousThenNextTwiceThenPreviousAgain()
+		{
+			history.MovePrevious();
+			history.MoveNext();
+			history.MoveNext();
+			history.MovePrevious();
+			Assert.AreEqual("b", history.Current);
+		}
 	}
 }

src/AddIns/BackendBindings/Python/PythonBinding/Test/Console/OneItemCommandLineHistoryTestFixture.cs

@@ -60,7 +60,7 @@ namespace PythonBinding.Tests.Console
 		{
 			history.MovePrevious();
 			history.MovePrevious();
-			Assert.IsNull(history.Current);
+			Assert.AreEqual("a", history.Current);
 		}		
 		
 		[Test]
@@ -75,7 +75,7 @@ namespace PythonBinding.Tests.Console
 		{
 			history.MovePrevious();
 			history.MoveNext();
-			Assert.IsNull(history.Current);
+			Assert.AreEqual("a", history.Current);
 		}
 				
 		[Test]