From 5db9ad5da775ff73aa8d859c334935d01f01b930 Mon Sep 17 00:00:00 2001
From: Dan Vanderkam <danvdk@gmail.com>
Date: Sat, 28 Mar 2015 14:31:57 -0400
Subject: [PATCH] Test non-existent divs

---
 auto_tests/tests/pathological_cases.js | 14 ++++++++++++++
 src/dygraph.js                         |  2 +-
 2 files changed, 15 insertions(+), 1 deletion(-)

diff --git a/auto_tests/tests/pathological_cases.js b/auto_tests/tests/pathological_cases.js
index ade714c..40e877f 100644
--- a/auto_tests/tests/pathological_cases.js
+++ b/auto_tests/tests/pathological_cases.js
@@ -160,4 +160,18 @@ it('testConstantSeriesNegativeIncludeZero', function() {
   assert.deepEqual([-1.1, 0], g.yAxisRange());
 });
 
+it('should throw with non-existent divs', function() {
+  var data = "X,Y\n" +
+             "1,-1\n" +
+             "2,1\n";
+
+  assert.throws(function() {
+    new Dygraph(null, data);
+  }, /non-existent div/);
+
+  assert.throws(function() {
+    new Dygraph('non-existent-div-id', data);
+  }, /non-existent div/);
+});
+
 });
diff --git a/src/dygraph.js b/src/dygraph.js
index 7121458..735ddca 100644
--- a/src/dygraph.js
+++ b/src/dygraph.js
@@ -403,7 +403,7 @@ Dygraph.prototype.__init__ = function(div, file, attrs) {
   }
 
   if (!div) {
-    throw 'Constructing dygraph with a non-existent div!';
+    throw new Error('Constructing dygraph with a non-existent div!');
   }
 
   // Copy the important bits into the object
-- 
2.7.4