From 75c7a68a63bdb17b94e3d90beecfae25d2a1f615 Mon Sep 17 00:00:00 2001
From: David Rupp <david@ruppworks.com>
Date: Sun, 17 Mar 2013 17:27:43 -0700
Subject: [PATCH] Added edges function.

---
 src/graffy/core.clj       |  4 ++++
 test/graffy/core_test.clj | 10 ++++++++++
 2 files changed, 14 insertions(+)

diff --git a/src/graffy/core.clj b/src/graffy/core.clj
index 3ef937b..7ac5475 100644
--- a/src/graffy/core.clj
+++ b/src/graffy/core.clj
@@ -4,6 +4,7 @@
   (add-node [this n])
   (add-edge [this s d])
   (nodes [this])
+  (edges [this n])
   (neighbors [this n]))
 
 (defn make-graph []
@@ -20,6 +21,9 @@
         this)
       (nodes [this]
         (keys @state))
+      (edges [this n]
+        (for [dest (neighbors this n)]
+          [n dest]))
       (neighbors [this n]
         (or (@state n)
             #{}))
diff --git a/test/graffy/core_test.clj b/test/graffy/core_test.clj
index d722043..5fc9dd1 100644
--- a/test/graffy/core_test.clj
+++ b/test/graffy/core_test.clj
@@ -16,3 +16,13 @@
       (is (= #{:b} (into #{} (neighbors g :a))))
       (is (= #{:a} (into #{} (neighbors g :b))))
       (is (= #{} (into #{} (neighbors g :c)))))))
+
+(deftest test-edges
+  (testing "edges"
+    (let [g (make-graph)]
+      (-> g (add-edge :a :b)
+            (add-edge :a :c)
+            (add-edge :a :d)
+            (add-edge :b :d))
+      (is (= #{[:a :b] [:a :c] [:a :d]} (into #{} (edges g :a))))
+      (is (= #{[:d :a] [:d :b]} (into #{} (edges g :d)))))))