#406 Url ctor that takes Uri

Test/Flurl.Test/UrlBuilderTests.cs

@@ -37,6 +37,14 @@ public class UrlBuilderTests
 			Assert.AreEqual("foo", url.Fragment);
 		}
 
+		[Test]
+		public void can_construct_from_uri() {
+			var s = "http://www.mysite.com/more?x=1&y=2#foo";
+			var uri = new Uri(s);
+			var url = new Url(uri);
+			Assert.AreEqual(s, url.ToString());
+		}
+
 		[Test]
 		public void can_parse_query_params() {
 			var q = new Url("http://www.mysite.com/more?x=1&y=2&z=3&y=4&abc&xyz&foo=&=bar&y=6").QueryParams;
@@ -199,7 +207,8 @@ public class UrlBuilderTests
 
 		[Test]
 		public void constructor_requires_nonnull_arg() {
-			Assert.Throws<ArgumentNullException>(() => new Url(null));
+			Assert.Throws<ArgumentNullException>(() => new Url((string)null));
+			Assert.Throws<ArgumentNullException>(() => new Url((Uri)null));
 		}
 
 		[Test]

src/Flurl/Url.cs

@@ -34,16 +34,32 @@ public class Url
 		/// </summary>
 		public QueryParamCollection QueryParams { get; private set; }
 
-	    /// <summary>
-	    /// Constructs a Url object from a string.
-	    /// </summary>
-	    /// <param name="baseUrl">The URL to use as a starting point (required)</param>
-	    /// <exception cref="ArgumentNullException"><paramref name="baseUrl"/> is <see langword="null" />.</exception>
-	    public Url(string baseUrl) {
+		/// <summary>
+		/// Constructs a Url object from a string.
+		/// </summary>
+		/// <param name="baseUrl">The URL to use as a starting point (required)</param>
+		/// <exception cref="ArgumentNullException"><paramref name="baseUrl"/> is <see langword="null" />.</exception>
+		public Url(string baseUrl) {
 			if (baseUrl == null)
 				throw new ArgumentNullException(nameof(baseUrl));
 
-			var parts = baseUrl.SplitOnFirstOccurence('#');
+			Parse(baseUrl);
+		}
+
+		/// <summary>
+		/// Constructs a Url object from a System.Uri.
+		/// </summary>
+		/// <param name="uri">The System.Uri (required)</param>
+		/// <exception cref="ArgumentNullException"><paramref name="uri"/> is <see langword="null" />.</exception>
+		public Url(Uri uri) {
+			if (uri == null)
+				throw new ArgumentNullException(nameof(uri));
+
+			Parse(uri.ToString());
+		}
+
+		private void Parse(string url) {
+			var parts = url.SplitOnFirstOccurence('#');
 			Fragment = (parts.Length == 2) ? parts[1] : "";
 			parts = parts[0].SplitOnFirstOccurence('?');
 			Query = (parts.Length == 2) ? parts[1] : "";