To have attribute improvement + improved test coverage

[Harry-Liversedge]

• Adds a parameter check to distinguish between toHaveAttribute('attrib') toHaveAttribute('attrib', 'value')
• Adds test cases for toHaveAttribute
• Updates all matchers that make use of toHaveAttribute
• Adds test cases for all matchers that make use of toHaveAttribute

In support of #2 improving unit test coverage
closes #438

[mgrybyk]

I'd only add tests and avoid refactoring of matchers.

[Harry-Liversedge]

That is what I initially was doing I do agree, but in #438 I had noticed that there was an unexpected behaviour whereby if you pass in a non-string it previously would always succeed i.e this test would fail:

test('failure with non-string attribute value as expected', async () => {
   el.getAttribute = jest.fn().mockImplementation((attribute: string) => {
      return "Correct Value"
   })
   const result = await toHaveAttribute(el, "attribute_name", 123, { ignoreCase: true });
   expect(result.pass).toBe(false)
})

[christian-bromann]

This looks good to me 👍

@mgrybyk good to merge from your side too?

[christian-bromann]

@Harry-Liversedge thanks so much for this contribution!