TestRestTemplate and spring security

I am learning spring rest. I am slowly building an application. I had full integration testing working well using TestRestTemplate.
However, I just started adding spring security to my application. Literally as soon as I add the spring security dependency, my testing fails.

<dependency>
    <groupId>org.springframework.boot</groupId>
    <artifactId>spring-boot-starter-security</artifactId>
</dependency>

I get these errors like so:

Error while extracting response for type [class [Lcom.myproject.model.viewobjects.AView;] and content type [application/json]; nested exception is org.springframework.http.converter.HttpMessageNotReadableException: JSON parse error: Cannot deserialize instance of `[Lcom.myproject.model.viewobjects.AView;` out of START_OBJECT token; nested exception is com.fasterxml.jackson.databind.exc.MismatchedInputException: Cannot deserialize instance of `[Lcom.myproject.model.viewobjects.AView;` out of START_OBJECT token
 at [Source: (PushbackInputStream); line: 1, column: 1]

When I debug, the object it returns which it is trying deserialize is null. If I put a breakpoint on the rest controller it doesn't even get there.

It seems like just adding the dependency turns a lot of defaults on. How do I test with security on? 1)Can I disable the security for testing somehow?

2)Can I somehow allow no credentials or send acceptable fake credentials? (I did see examples of @WithMockUser but that doesn't work with TestRestTemplate)

Edit: I tried adding a security implementation to my test class to enable anonymous access and permitall:

@EnableWebSecurity
class TestSecurityConfig extends WebSecurityConfigurerAdapter
    {
    @Override
    protected void configure(HttpSecurity http) throws Exception
        {
        http.anonymous().and().authorizeRequests().antMatchers("/**").permitAll();
        }
    }

The result of this is that @GetMapping work. I can trace that the calls reach the controller. But @PostMapping still do not work. The calls never reach the controller. The post calls look like so:

updatedAView = restTemplate.postForObject(create_aview_url, aView, AView.class);

Why would get work but not post??? Also, to make sure there wasn't something else, I again went and removed the spring-boot-starter-security dependency and all the code that relates. Suddenly everything works. So it is definitely the security config that does this.