test: add bargap 0 mock

Author: etpinard

test/image/baselines/bar_bargap0.png

@@ -0,0 +1,40 @@
+{
+  "data": [
+    {
+      "x": [
+        "giraffes",
+        "orangutans",
+        "monkeys"
+      ],
+      "y": [
+        20,
+        14,
+        23
+      ],
+      "name": "SF Zoo",
+      "type": "bar"
+    }
+  ],
+  "layout": {
+    "bargap": 0,
+    "xaxis": {
+      "type": "category",
+      "range": [
+        -0.5,
+        2.5
+      ],
+      "autorange": true
+    },
+    "yaxis": {
+      "type": "linear",
+      "range": [
+        0,
+        24.210526315789473
+      ],
+      "autorange": true
+    },
+    "height": 450,
+    "width": 1100,
+    "autosize": false
+  }
+}