add regression test

e2etests/regression_test.go

@@ -248,6 +248,20 @@ code: |go
     b := a + 7
     fmt.Printf("%d", b)
 |
+`,
+		},
+		{
+			name: "elk_img_empty_label_panic",
+			script: `
+img: {
+	label: ""
+	shape: image
+	icon: https://icons.terrastruct.com/infra/019-network.svg
+}
+ico: {
+	label: ""
+	icon: https://icons.terrastruct.com/infra/019-network.svg
+}
 `,
 		},
 	}

e2etests/testdata/regression/elk_img_empty_label_panic/dagre/board.exp.json

@@ -0,0 +1,57 @@
+{
+  "name": "",
+  "fontFamily": "SourceSansPro",
+  "shapes": [
+    {
+      "id": "img",
+      "type": "image",
+      "pos": {
+        "x": 0,
+        "y": 0
+      },
+      "width": 128,
+      "height": 128,
+      "opacity": 1,
+      "strokeDash": 0,
+      "strokeWidth": 2,
+      "borderRadius": 0,
+      "fill": "#FFFFFF",
+      "stroke": "#0D32B2",
+      "shadow": false,
+      "3d": false,
+      "multiple": false,
+      "tooltip": "",
+      "link": "",
+      "icon": {
+        "Scheme": "https",
+        "Opaque": "",
+        "User": null,
+        "Host": "icons.terrastruct.com",
+        "Path": "/infra/019-network.svg",
+        "RawPath": "",
+        "ForceQuery": false,
+        "RawQuery": "",
+        "Fragment": "",
+        "RawFragment": ""
+      },
+      "iconPosition": "INSIDE_MIDDLE_CENTER",
+      "blend": false,
+      "fields": null,
+      "methods": null,
+      "columns": null,
+      "label": "",
+      "fontSize": 16,
+      "fontFamily": "DEFAULT",
+      "language": "",
+      "color": "#0A0F25",
+      "italic": false,
+      "bold": true,
+      "underline": false,
+      "labelWidth": 0,
+      "labelHeight": 0,
+      "zIndex": 0,
+      "level": 1
+    }
+  ],
+  "connections": []
+}

e2etests/testdata/regression/elk_img_empty_label_panic/dagre/sketch.exp.svg

@@ -0,0 +1,24 @@
+<?xml version="1.0" encoding="utf-8"?>
+<svg
+style="background: white;"
+xmlns="http://www.w3.org/2000/svg" xmlns:xlink="http://www.w3.org/1999/xlink"
+width="328" height="328" viewBox="-100 -100 328 328"><style type="text/css">
+<![CDATA[
+.shape {
+  shape-rendering: geometricPrecision;
+  stroke-linejoin: round;
+}
+.connection {
+  stroke-linecap: round;
+  stroke-linejoin: round;
+}
+.blend {
+  mix-blend-mode: multiply;
+  opacity: 0.5;
+}
+
+]]>
+</style><g id="img"><g class="shape" ><image href="https://icons.terrastruct.com/infra/019-network.svg" x="0" y="0" width="128" height="128" style="fill:#FFFFFF;stroke:#0D32B2;opacity:1.000000;stroke-width:2;" /></g></g><mask id="1647785219" maskUnits="userSpaceOnUse" x="-100" y="-100" width="328" height="328">
+<rect x="-100" y="-100" width="328" height="328" fill="white"></rect>
+
+</mask><style type="text/css"><![CDATA[]]></style></svg>