Use createSinonStub

src/core/client/framework/testHelpers/createSinonStub.ts

@@ -1,5 +1,25 @@
 import sinon, { SinonStub } from "sinon";
 
+/**
+ * createSinonStub assist in setting up a stub with different
+ * return paths.
+ *
+ * e.g.
+ * ```
+ * const s = sinon.stub();
+ * s.throws();
+ * s.withArgs("a").returns(0);
+ * s.withArgs("b").returns(1);
+ * ```
+ * is equivalent to.
+ * ```
+ * const s = createSinonStub(
+ *   s => s.throws(),
+ *   s => s.withArgs("a").returns(0),
+ *   s => s.withArgs("b").returns(1),
+ * );
+ * ```
+ */
 export default function createSinonStub(
   ...callbacks: Array<(s: SinonStub) => void>
 ): SinonStub {