Add tests for declaform.

tsconfig.json

@@ -7,6 +7,7 @@
 
     // Environment Settings
     // See also https://aka.ms/tsconfig/module
+    "esModuleInterop": true,
     "module": "esnext",
     "target": "es6",
     "types": [],
@@ -40,5 +41,6 @@
     "noUncheckedSideEffectImports": true,
     "moduleDetection": "force",
     "skipLibCheck": true,
-  }
+  },
+  "exclude": ["./src/**/*.test.ts"]
 }