Add GetEndpoint test case for EndpointFunc and fix empty request handling

[sonnes]

No description provided.

[codecov-commenter]

Codecov Report

❌ Patch coverage is 57.14286% with 3 lines in your changes missing coverage. Please review.
✅ Project coverage is 83.58%. Comparing base (6ce2a14) to head (793c488).

Files with missing lines	Patch %	Lines
xapi/endpoint.go	57.14%	2 Missing and 1 partial ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main      #66      +/-   ##
==========================================
+ Coverage   83.30%   83.58%   +0.27%     
==========================================
  Files          60       60              
  Lines        2810     2224     -586     
==========================================
- Hits         2341     1859     -482     
+ Misses        456      351     -105     
- Partials       13       14       +1     

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