how to test if rest api login code example

Example 1: how do you do positive api testing

How I do positive testing in api, 
	- I send valid path and query parameters, 
	- valid headers, 
	- valid request body to valid url and verify that 
	- response status code is correct and 
	- response body is as expected
    
How I do negative testing in api,
	- I send invalid request parameters
	- or invalid headers
	- or invalid request json body and verify 
    that response status code is not 200 
	- and response body contains error message 
    (for example there are 100 employees numbered
    from 1 to 100 I send 101 as a parameter and I
    should be able see 404 Not Found 
    The requested resource was not found.)

Example 2: api test strategy

API test strategy 
API testing involves APIs directly
and checks whether the API meets
expectations in terms of functionality,
reliability, performance, and security
of an application. My first concern is
functional testing which ensures that
the API functions correctly.
The main objectives in functional
testing of the API are: 
•	to ensure that the implementation
is working correctly as expected - no bugs!
•	to ensure that the implementation
is working as specified according
to API documentation.
•	to prevent regressions between
code merges and releases.