Fix TSR  for / nodes before param nodes

Fixes #90

tree.go

diff --git a/tree.go b/tree.go
index a15bc2c..af95bd4 100644
--- a/tree.go
+++ b/tree.go
@@ -33,9 +33,10 @@
 type nodeType uint8
 
 const (
-	static   nodeType = 0
-	param    nodeType = 1
-	catchAll nodeType = 2
+	static nodeType = iota // default
+	root
+	param
+	catchAll
 )
 
 type node struct {
@@ -195,6 +196,7 @@
 		}
 	} else { // Empty tree
 		n.insertChild(numParams, path, fullPath, handle)
+		n.nType = root
 	}
 }
 
@@ -411,6 +413,11 @@
 				return
 			}
 
+			if path == "/" && n.wildChild && n.nType != root {
+				tsr = true
+				return
+			}
+
 			// No handle found. Check if a handle for this path + a
 			// trailing slash exists for trailing slash recommendation
 			for i := 0; i < len(n.indices); i++ {

tree_test.go

diff --git a/tree_test.go b/tree_test.go
index 64f26d1..46d3299 100644
--- a/tree_test.go
+++ b/tree_test.go
@@ -89,7 +89,7 @@
 			maxParams = params
 		}
 	}
-	if n.nType != static && !n.wildChild {
+	if n.nType > root && !n.wildChild {
 		maxParams++
 	}
 
@@ -394,6 +394,9 @@
 		"/1/:id/2",
 		"/aa",
 		"/a/",
+		"/admin",
+		"/admin/:category",
+		"/admin/:category/:page",
 		"/doc",
 		"/doc/go_faq.html",
 		"/doc/go1.html",
@@ -423,6 +426,9 @@
 		"/0/go/",
 		"/1/go",
 		"/a",
+		"/admin/",
+		"/admin/config/",
+		"/admin/config/permissions/",
 		"/doc/",
 	}
 	for _, route := range tsrRoutes {
@@ -452,6 +458,24 @@
 	}
 }
 
+func TestTreeRootTrailingSlashRedirect(t *testing.T) {
+	tree := &node{}
+
+	recv := catchPanic(func() {
+		tree.addRoute("/:test", fakeHandler("/:test"))
+	})
+	if recv != nil {
+		t.Fatalf("panic inserting test route: %v", recv)
+	}
+
+	handler, _, tsr := tree.getValue("/")
+	if handler != nil {
+		t.Fatalf("non-nil handler")
+	} else if tsr {
+		t.Errorf("expected no TSR recommendation")
+	}
+}
+
 func TestTreeFindCaseInsensitivePath(t *testing.T) {
 	tree := &node{}