MockMvc : handling unique constraints - spring-boot

Question

In my project I have a unique constraint on a name value which I annotated like so:
#Column(unique = true)
protected String name;
this is fine, and works...what I want to do in the project deployment, is when a user tries to enter an object in the database with a name that already exists, they'll be presented with an error message "an entry with that name already exists" or something similar and then be redirected back to their form.
In testing with MockMvc, I have something like this:
try {
mockMvc.perform(post(uri)
.contentType(MediaType.APPLICATION_JSON)
.content(widgetJson)
.accept(MediaType.APPLICATION_JSON))
.andDo(print())
.andExpect(status().isNotFound());
} catch (Exception e) {
logger.error("we got expected exception here", e);
threwException = true;
e.printStackTrace();
}
after that block, if the threwException var is false, the test fails. Normally, I do not have try/catch in my MockMvc unit tests, rather a throws Exception in the signature.
The way I have it now works, and gives me the results I expect, but I don't get a response. I tried adding a MvcResult result = before the perform call, and adding the .andReturn() at the end, but I never get an actual response and can't determine what the response code is.
I figure this has to be a pretty common use case and was wondering if there is a best practice as to how to set up the test.
thanks!

Answer 1

This might help to solve your problem:
MvcResult result = null;
try {
ResultActions resultActions = mockMvc.perform(post(uri)
.contentType(MediaType.APPLICATION_JSON)
.content(widgetJson)
.accept(MediaType.APPLICATION_JSON));
result = resultActions.andReturn();
resultActions
.andDo(print())
.andExpect(status().isNotFound());
} catch (Exception e) {
if(result != null) {
logger.error("Response Body", result.getResponse().getContentAsString());
logger.error("Response Status", result.getResponse().getStatus() ());
}
logger.error("we got expected exception here", e);
threwException = true;
e.printStackTrace();
}
Reference:
https://docs.spring.io/spring-framework/docs/current/javadoc-api/org/springframework/test/web/servlet/MvcResult.html#getResponse--
https://docs.spring.io/spring-framework/docs/current/javadoc-api/org/springframework/mock/web/MockHttpServletResponse.html#getContentAsString--
https://docs.spring.io/spring-framework/docs/current/javadoc-api/org/springframework/test/web/servlet/ResultActions.html#andReturn--