contrib/gin-gonic: add option to ignore request

[mackjmr]

This PR add's an option to ignore requests for contrib/gin-gonic.

Fixes: #1060

[gbbr]

Looks good! Just a few nits.

[gbbr]

Suggested change

	mt := mocktracer.Start()
	defer mt.Stop()
	r := httptest.NewRequest("GET", "http://localhost"+test.url, nil)
	w := httptest.NewRecorder()
	router.ServeHTTP(w, r)
	spans := mt.FinishedSpans()
	assert.Equal(t, test.spanCount, len(spans))
	mt := mocktracer.Start()
	defer mt.Reset()
	r := httptest.NewRequest("GET", "http://localhost"+test.url, nil)
	router.ServeHTTP(httptest.NewRecorder(), r)
	assert.Equal(t, test.spanCount, len(mt.FinishedSpans()))

No need to create variables that are not used. Also, we can use Reset instead of Stop, on the mocktracer.

[mackjmr]

Sounds good, addressed in latest commit.

[gbbr]

I would prefer it if we didn't create the tests variable. There is no need for it, it's not used in more than one place. You can just inline all the tests. If you like (up to you), it could also be a map:

Suggested change

	for _, test := range tests {
	for path, count := range map[string]int{
	"/OK": 1,
	// ...
	} {

[prithvihv]

can add a field called expectedToSkip bool (to represent a table driven tests).

[gbbr]

Perhaps you can meet both the suggested requirements by doing something like this:

for path, shouldSkip := range map[string]bool{
    "/OK": false,
    // ...
} {
   // ...
}

[mackjmr]

Sounds good, made the change 👍

[gbbr]

Wonderful! Thank you!