add tests for legend resize and this forum [post](http://community.pl…

…ot.ly/t/default-showlegend-changed-with-update/708)

test/jasmine/tests/legend_scroll_test.js

@@ -20,6 +20,11 @@ describe('The legend', function() {
         return gd._fullLayout._topdefs.selectAll('#legend' + uid).size();
     }
 
+    function getPlotHeight(gd) {
+        return gd._fullLayout.height - gd._fullLayout.margin.t - gd._fullLayout.margin.b;
+    }
+
+
     describe('when plotted with many traces', function() {
         beforeEach(function() {
             gd = createGraph();
@@ -30,10 +35,9 @@ describe('The legend', function() {
         afterEach(destroyGraph);
 
         it('should not exceed plot height', function() {
-            var legendHeight = getBBox(legend).height,
-                plotHeight = gd._fullLayout.height - gd._fullLayout.margin.t - gd._fullLayout.margin.b;
+            var legendHeight = getBBox(legend).height;
 
-            expect(+legendHeight).toBe(plotHeight);
+            expect(+legendHeight).toBe(getPlotHeight(gd));
         });
 
         it('should insert a scrollbar', function() {
@@ -88,10 +92,29 @@ describe('The legend', function() {
                 done();
             });
         });
+
+        it('should resize when relayout\'ed with new height', function(done) {
+            var origLegendHeight = getBBox(legend).height;
+
+            Plotly.relayout(gd, {'height': gd._fullLayout.height/2}).then(function() {
+                var legendHeight = getBBox(legend).height;
+
+                //legend still exists and not duplicated
+                expect(countLegendGroups(gd)).toBe(1);
+                expect(countLegendClipPaths(gd)).toBe(1);
+
+                // clippath resized to new height less than new plot height
+                expect(+legendHeight).toBe(getPlotHeight(gd));
+                expect(+legendHeight).toBeLessThan(+origLegendHeight);
+
+                done();
+            });
+        });
     });
 
+
     describe('when plotted with few traces', function() {
-        var gd;
+        var gd, legend;
 
         beforeEach(function() {
             gd = createGraph();
@@ -122,6 +145,21 @@ describe('The legend', function() {
                 done();
             });
         });
+
+        it('should resize when traces added', function(done) {
+            legend = document.getElementsByClassName('legend')[0];
+            var origLegendHeight = getBBox(legend).height;
+
+            Plotly.addTrace(gd, { x: [1,2,3], y: [4,3,2], name: 'Test2' }).then(function() {
+                var legend = document.getElementsByClassName('legend')[0];
+                var legendHeight = getBBox(legend).height;
+                // clippath resized to show new trace
+                expect(+legendHeight).toBeCloseTo(+origLegendHeight+18, 0);
+
+                done();
+            });
+
+        });
     });
 });