fix tests

Author: gfx

test/ExtensionCodec.test.ts

@@ -98,16 +98,22 @@ describe("ExtensionCodec", () => {
 
   context("custom extensions with custom context", () => {
     class Context {
+      public ctxVal: number;
       public expectations: Array<any> = [];
-      constructor(public ctxVal: number) {}
+      constructor(ctxVal: number) {
+        this.ctxVal = ctxVal;
+      }
       public hasVisited(val: any) {
         this.expectations.push(val);
       }
     }
     const extensionCodec = new ExtensionCodec<Context>();
 
     class Magic<T> {
-      constructor(public val: T) {}
+      public val: T;
+      constructor(val: T) {
+        this.val = val;
+      }
     }
 
     // Magic