jasmine tests for Sankey - warning / error test (and defaults.js improv)

Author: monfera

src/traces/sankey/defaults.js

@@ -83,11 +83,11 @@ module.exports = function supplyDefaults(traceIn, traceOut, defaultColor, layout
     };
 
     if(traceOut.node.label.some(missing)) {
-        Lib.log('Some of the nodes are neither sources nor targets, please remove them.');
+        Lib.warn('Some of the nodes are neither sources nor targets, please remove them.');
     }
 
     if(circularityPresent(traceOut.node.label, traceOut.link.source, traceOut.link.target)) {
-        Lib.log('Circularity is present in the Sankey data. Removing all nodes and links.');
+        Lib.error('Circularity is present in the Sankey data. Removing all nodes and links.');
         traceOut.link.label = [];
         traceOut.link.source = [];
         traceOut.link.target = [];

test/jasmine/tests/sankey_test.js

@@ -2,7 +2,7 @@ var Lib = require('@src/lib');
 var Sankey = require('@src/traces/sankey');
 var attributes = require('@src/traces/sankey/attributes');
 
-describe('sankey initialization tests', function() {
+describe('sankey tests', function() {
 
     'use strict';
 
@@ -88,6 +88,54 @@ describe('sankey initialization tests', function() {
 
     });
 
+    describe('log warning if issue is encountered with graph structure',
+        function() {
+
+            it('some nodes are not linked', function() {
+
+                var warnings = [];
+                spyOn(Lib, 'warn').and.callFake(function(msg) {
+                    warnings.push(msg);
+                });
+
+                _supply({
+                    node: {
+                        label: ['a', 'b', 'c']
+                    },
+                    link: {
+                        value: [1],
+                        source: [0],
+                        target: [1]
+                    }
+                });
+
+                expect(warnings.length).toEqual(1);
+            });
+
+            it('circularity is detected', function() {
+
+                var errors = [];
+                spyOn(Lib, 'error').and.callFake(function(msg) {
+                    errors.push(msg);
+                });
+
+                _supply({
+                    node: {
+                        label: ['a', 'b', 'c']
+                    },
+                    link: {
+                        value: [1, 1, 1],
+                        source: [0, 1, 2],
+                        target: [1, 2, 0]
+                    }
+                });
+
+                expect(errors.length).toEqual(1);
+            });
+
+
+        });
+
     describe('sankey defaults', function() {
 
         it('\'Sankey\' specification should have proper arrays where mandatory',