Add tsconfig.karma and fix karma tests

Author: cgewecke

karma.conf.js

@@ -13,7 +13,8 @@ module.exports = function (config) {
     karmaTypescriptConfig: {
       bundlerOptions: {
         entrypoints: /\.spec\.ts$/
-      }
+      },
+      tsconfig: "./tsconfig.karma.json",
     },
 
     browsers: ['FirefoxHeadless', 'ChromeHeadless'],

tsconfig.karma.json

@@ -0,0 +1,10 @@
+{
+  "extends": "@ethereumjs/config-typescript",
+  "include": ["bin", "lib", "test"],
+  "compilerOptions": {
+    "typeRoots": [
+      "node_modules/@polkadot/ts"
+    ],
+    "skipLibCheck": true
+  }
+}