Fixed Identifier.TryParse to not throw when passed null or empty string values.

Fixes Trac issue 15.

2 files changed, 21 insertions, 1 deletions

diff --git a/src/DotNetOpenAuth.Test/OpenId/IdentifierTests.cs b/src/DotNetOpenAuth.Test/OpenId/IdentifierTests.cs
index 2b012dd..53df6c8 100644
--- a/src/DotNetOpenAuth.Test/OpenId/IdentifierTests.cs
+++ b/src/DotNetOpenAuth.Test/OpenId/IdentifierTests.cs
@@ -19,6 +19,22 @@ namespace DotNetOpenAuth.Test.OpenId {
 		private string xri = "=arnott*andrew";
 
 		[TestMethod]
+		public void TryParseNoThrow() {
+			Identifier id;
+			Assert.IsFalse(Identifier.TryParse(null, out id));
+			Assert.IsFalse(Identifier.TryParse("", out id));
+		}
+
+		[TestMethod]
+		public void TryParse() {
+			Identifier id;
+			Assert.IsTrue(Identifier.TryParse("http://host/path", out id));
+			Assert.AreEqual("http://host/path", id.ToString());
+			Assert.IsTrue(Identifier.TryParse("=arnott", out id));
+			Assert.AreEqual("=arnott", id.ToString());
+		}
+
+		[TestMethod]
 		public void Parse() {
 			Assert.IsInstanceOfType(Identifier.Parse(this.uri), typeof(UriIdentifier));
 			Assert.IsInstanceOfType(Identifier.Parse(this.xri), typeof(XriIdentifier));
diff --git a/src/DotNetOpenAuth/OpenId/Identifier.cs b/src/DotNetOpenAuth/OpenId/Identifier.cs
index 53f5094..1b9570e 100644
--- a/src/DotNetOpenAuth/OpenId/Identifier.cs
+++ b/src/DotNetOpenAuth/OpenId/Identifier.cs
@@ -114,7 +114,11 @@ namespace DotNetOpenAuth.OpenId {
 		/// True if the operation was successful.  False if the string was not a valid OpenId Identifier.
 		/// </returns>
 		public static bool TryParse(string value, out Identifier result) {
-			Contract.Requires(!string.IsNullOrEmpty(value));
+			if (string.IsNullOrEmpty(value)) {
+				result = null;
+				return false;
+			}
+
 			if (IsValid(value)) {
 				result = Parse(value);
 				return true;