add mocks and baselines for circular Sankey

Author: antoinerg

test/image/baselines/sankey_circular.png

@@ -3,7 +3,7 @@
         {
             "type": "sankey",
             "node": {
-                "pad": 1,
+                "pad": 5,
                 "label": ["0", "1", "2", "3", "4", "5", "6"]
             },
             "link": {

test/image/baselines/sankey_circular_process.png

@@ -0,0 +1,20 @@
+{
+  "data": [{
+    "type": "sankey",
+    "node": {
+      "pad": 5,
+      "label": ["startA", "startB", "process1", "process2", "process3", "process4", "process5", "process6", "process7", "process8", "process9", "process10", "process11", "process12", "process13", "process14", "process15", "process16", "finishA", "finishB"]
+    },
+    "link": {
+      "source": [0, 0, 0, 1, 1, 2, 5, 3, 2, 6, 7, 5, 7, 5, 4, 4, 16, 14, 8, 9, 9, 17, 9, 12, 5, 13, 8, 16, 11, 11, 15, 10, 17, 10, 16, 16, 12],
+      "target": [9, 6, 7, 2, 6, 5, 2, 8, 4, 2, 0, 3, 9, 1, 3, 1, 14, 10, 1, 2, 17, 10, 12, 11, 13, 12, 16, 15, 14, 17, 19, 18, 9, 19, 19, 18, 16],
+      "value": [20, 20, 20, 15, 15, 30, 10, 35, 20, 20, 5, 5, 15, 5, 15, 5, 10, 10, 20, 10, 10, 10, 25, 20, 10, 10, 15, 10, 10, 10, 10, 10, 10, 10, 10, 10, 25]
+    }
+  }],
+  "layout": {
+    "title": "Example process",
+    "margin": {"t": 100, "b": 0, "l": 25, "r": 25},
+    "width": 1000,
+    "height": 800
+  }
+}