diff --git a/OpenRa.TechTreeTest/Building.cs b/OpenRa.TechTreeTest/Building.cs
index d11b8882d5..6347c72f8e 100644
--- a/OpenRa.TechTreeTest/Building.cs
+++ b/OpenRa.TechTreeTest/Building.cs
@@ -46,6 +46,12 @@ namespace OpenRa.TechTreeTest
 
 		public bool ShouldMakeBuildable(IEnumerable<string> buildings)
 		{
+			if (techLevel > 10 || techLevel < 0)
+				return false;
+
+			if (prerequisites.Length == 0)
+				return true;
+
 			List<string> p = new List<string>(prerequisites);
 			foreach (string b in buildings)
 				p.Remove(b);
@@ -55,6 +61,9 @@ namespace OpenRa.TechTreeTest
 
 		public bool ShouldMakeUnbuildable(IEnumerable<string> buildings)
 		{
+			if (prerequisites.Length == 0)
+				return false;
+
 			List<string> p = new List<string>(prerequisites);
 			foreach (string b in buildings)
 				p.Remove(b);
diff --git a/OpenRa.TechTreeTest/TechTree.cs b/OpenRa.TechTreeTest/TechTree.cs
index 92c9c0100e..b310f58a03 100644
--- a/OpenRa.TechTreeTest/TechTree.cs
+++ b/OpenRa.TechTreeTest/TechTree.cs
@@ -29,7 +29,7 @@ namespace OpenRa.TechTreeTest
 				IniSection section = rulesFile.GetSection(key);
 				Building b = buildings[key];
 				string s = section.GetValue("Prerequisite", "").ToUpper();
-				b.Prerequisites = s.Split(',');
+				b.Prerequisites = s.Split(new char[] { ',' }, StringSplitOptions.RemoveEmptyEntries);
 				b.TechLevel = int.Parse(section.GetValue("TechLevel", "-1"));
 			}
 		}