[Backport 2.x] add checks to existing unit tests

[opensearch-trigger-bot]

Backport c098d8b from #1104.

[dblock]

@al-niessner looks like the backport failed as expected, I hear @Xtansia is looking into it, but don't hold back if you know/have/want to try a fix before him

[al-niessner]

I am really shooting in the dark here but will give a whirl.

[al-niessner]

@dblock @Xtansia @jordanpadams @tloubrieu-jpl

I traced it down to PathEncoder and it is exactly what @Xtansia thought. I reduced the checks to:

    String base = "a:b:c::2.0";
    String expected = "/a%3Ab%3Ac%3A%3A2.0";
    assertEquals(expected, org.apache.http.client.utils.URLEncodedUtils.formatSegments(base));
    assertEquals(expected, org.apache.http.client.utils.URLEncodedUtils.formatSegments(Collections.singletonList(base), StandardCharsets.UTF_8));
    assertEquals(expected, org.apache.hc.core5.net.URLEncodedUtils.formatSegments(Collections.singletonList(base), StandardCharsets.UTF_8));

The simplest thing to say is that org.apache.http.client.utils.URLEncodedUtils.formatSegments() does not treat the ':' as a special character while org.apache.hc.core5.net.URLEncodedUtils.formatSegments() does. Other than altering apache code and waiting for its next release or rolling your own encoder fraught with all of its own problems, there is no solution here.

Do you have a snapshot or future release that is based solely on httpClient5? I know this potentially introduces a host of new problems, but at least they will be consistent to fix.

Actual errorr:

org.junit.ComparisonFailure: expected:</a[%3Ab%3Ac%3A%3A]2.0> but was:</a[:b:c::]2.0>

[al-niessner]

Oh, you know what. We can reverse the checks in PathEncoder so that if it finds httpClient5 first then use it but fail back to 4 with all of its known warts. This would essentially fix our problem because httpClient5 is in our classpath already for localhost issues. Would you be alright with such a change?

[al-niessner]

Now I understand what you mean by 2.x prioritizing apache 4. My suggestion above is in contrast to idea.