fix unit tests

Signed-off-by: Roman <ixrock@gmail.com>

__mocks__/assetMock.ts

@@ -3,4 +3,4 @@
  * Licensed under MIT License. See LICENSE in root directory for more information.
  */
 
-export default {};
+export default ""; // mostly path to bundled file or data-url (webpack)

package.json

@@ -62,7 +62,7 @@
     },
     "moduleNameMapper": {
       "\\.(css|scss)$": "<rootDir>/__mocks__/styleMock.ts",
-      "\\.(svg)$": "<rootDir>/__mocks__/imageMock.ts"
+      "\\.(svg|png|jpg|eot|woff2?|ttf)$": "<rootDir>/__mocks__/assetMock.ts"
     },
     "modulePathIgnorePatterns": [
       "<rootDir>/dist",

src/renderer/components/icon/icon.tsx

@@ -104,8 +104,9 @@ export class Icon extends React.PureComponent<IconProps> {
     // render as inline svg-icon
     if (typeof svg === "string") {
       const dataUrlPrefix = "data:image/svg+xml;base64,";
-      const svgIconDataUrl: string = svg.startsWith(dataUrlPrefix) ? svg : require(`./${svg}.svg`);
-      const svgIconText = decode(svgIconDataUrl.replace(dataUrlPrefix, "")); // get raw xml
+      const svgIconDataUrl = svg.startsWith(dataUrlPrefix) ? svg : require(`./${svg}.svg`);
+      const svgIconText = typeof svgIconDataUrl == "string" // decode xml from data-url
+        ? decode(svgIconDataUrl.replace(dataUrlPrefix, "")) : "";
 
       iconContent = <span className="icon" dangerouslySetInnerHTML={{ __html: svgIconText }} />;
     }

types/mocks.d.ts

@@ -27,6 +27,7 @@ declare module "*.scss" {
 }
 
 // Declare everything what's bundled as webpack's type="asset/resource"
+// Should be mocked for tests support in jestConfig.moduleNameMapper (currently in "/package.json")
 declare module "*.svg";
 declare module "*.jpg";
 declare module "*.png";