test: add more mock images of bar plots

* Added mock images of bar plots using the attributes base, offset and
  width.

Author: n-riesco

test/image/baselines/bar_attrs_group.png

@@ -0,0 +1,33 @@
+{
+    "data":[
+        {
+            "base":[0,1,2,3],
+            "width":0.2,
+            "y":[1,1,1,1],
+            "x":[1,2,3,4],
+            "type":"bar"
+        }, {
+            "base":[4,3,2,1],
+            "y":[-1,-1,-1,-1],
+            "x":[1,2,3,4],
+            "type":"bar"
+        }, {
+            "base":[0,1,3,2],
+            "width":0.125,
+            "y":[1,2,-1,2],
+            "x":[1,2,3,4],
+            "type":"bar"
+        }, {
+            "base":[1,3,2,4],
+            "y":[-1,-2,1,-2],
+            "x":[1,2,3,4],
+            "type":"bar"
+        }
+    ],
+    "layout":{
+        "height":400,
+        "width":400,
+        "barmode":"group",
+        "barnorm":false
+    }
+}

test/image/baselines/bar_attrs_group_norm.png

@@ -0,0 +1,19 @@
+{
+    "data":[
+        {
+            "base":4,
+            "x":[3,2,1,0],
+            "type":"bar"
+        }, {
+            "base":[7,6,5,4],
+            "x":[1,2,3,4],
+            "type":"bar"
+        }
+    ],
+    "layout":{
+        "height":400,
+        "width":400,
+        "barmode":"group",
+        "barnorm":"percent"
+    }
+}

test/image/baselines/bar_attrs_overlay.png

@@ -0,0 +1,38 @@
+{
+    "data":[
+        {
+            "base":[0,1,2,3],
+            "width":[1,0.8,0.6,0.4],
+            "offset":[0,0,-0.2,-0.6],
+            "y":[1,1,1,1],
+            "x":[1,2,3,4],
+            "type":"bar"
+        }, {
+            "base":[4,3,2,1],
+            "width":[0.4,0.6,0.8,1],
+            "offset":[-0.2,-0.8,-1.2,-1.4],
+            "y":[-1,-1,-1,-1],
+            "x":[5,6,7,8],
+            "type":"bar"
+        }, {
+            "base":[0,1,3,2],
+            "width":1,
+            "offset":[1.5],
+            "y":[1,2,-1,2],
+            "x":[9,10,11,12],
+            "type":"bar"
+        }, {
+            "base":[1,3,2,4],
+            "y":[-1,-2,1,-2],
+            "x":[13,14,15,16],
+            "type":"bar"
+        }
+    ],
+    "layout":{
+        "xaxis": {"showgrid":true},
+        "height":400,
+        "width":400,
+        "barmode":"overlay",
+        "barnorm":false
+    }
+}

test/image/baselines/bar_attrs_relative.png

@@ -0,0 +1,31 @@
+{
+    "data":[
+        {
+            "width":[1,0.8,0.6,0.4],
+            "y":[1,2,3,4],
+            "x":[1,2,3,4],
+            "type":"bar"
+        }, {
+            "width":[0.4,0.6,0.8,1],
+            "y":[3,2,1,0],
+            "x":[1,2,3,4],
+            "type":"bar"
+        }, {
+            "width":1,
+            "y":[-1,-3,-2,-4],
+            "x":[1,2,3,4],
+            "type":"bar"
+        }, {
+            "y":[0,-1,-3,-2],
+            "x":[1,2,3,4],
+            "type":"bar"
+        }
+    ],
+    "layout":{
+        "xaxis": {"showgrid":true},
+        "height":400,
+        "width":400,
+        "barmode":"relative",
+        "barnorm":false
+    }
+}