Jest testing snippets

Jest testing snippets.md

Mocking console.error

Requires jsdom

describe("module", () => {
  beforeAll(() => {
    jest.spyOn(console, "error").mockImplementation(() => {});
  });

  it("should read valid data from localStorage", () => {
    expect(console.error).toBeCalledWith(
      expect.stringContaining("Unable to parse data from serialised JSON")
    );
  });
});