Spring Boot org.springframework.web.util.NestedServletException caused by missing resource

I am testing that if there is no charity with the ID specified, the page should show the 404 page which contains the string "No matching charity". I have done...

@Test
    public void shouldReturn404IfThereIsNoMatchingCharity() throws Exception {
        Charity nspcc = new Charity(1L,
                "12345678",
                "National Society for the Prevention of Cruelty to Children",
                "Kids charity",
                "nspcc",
                "NSPCC",
                true);

        given(charityService.findById(1L)).willReturn(Optional.of(nspcc));
        given(charityService.findById(2L)).willReturn(Optional.empty());

        this.mockMvc.perform(get("/charity/2"))
                .andDo(print())
                .andExpect(status().isNotFound())
                .andExpect(content()
                        .string(containsString("No matching charity")));
    }

But I get this error:

org.springframework.web.util.NestedServletException: Request processing failed; nested exception is com.nsa.charitystarter.controllers.exceptions.MissingResourceException: No matching charity

at org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:1013) at org.springframework.web.servlet.FrameworkServlet.doGet(FrameworkServlet.java:897) at javax.servlet.http.HttpServlet.service(HttpServlet.java:634) at org.springframework.web.servlet.FrameworkServlet.service(FrameworkServlet.java:882) at org.springframework.test.web.servlet.TestDispatcherServlet.service(TestDispatcherServlet.java:71) at javax.servlet.http.HttpServlet.service(HttpServlet.java:741) at org.springframework.mock.web.MockFilterChain$ServletFilterProxy.doFilter(MockFilterChain.java:166) at org.springframework.mock.web.MockFilterChain.doFilter(MockFilterChain.java:133) at org.springframework.web.filter.RequestContextFilter.doFilterInternal(RequestContextFilter.java:99) at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:118) at org.springframework.mock.web.MockFilterChain.doFilter(MockFilterChain.java:133) at org.springframework.web.filter.FormContentFilter.doFilterInternal(FormContentFilter.java:92) at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:118) at org.springframework.mock.web.MockFilterChain.doFilter(MockFilterChain.java:133) at org.springframework.web.filter.HiddenHttpMethodFilter.doFilterInternal(HiddenHttpMethodFilter.java:93) at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:118) at org.springframework.mock.web.MockFilterChain.doFilter(MockFilterChain.java:133) at org.springframework.test.web.servlet.MockMvc.perform(MockMvc.java:182) at com.nsa.charitystarter.controllers.CharityProfileTest.shouldReturn404IfThereIsNoMatchingCharity(CharityProfileTest.java:69) at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke0(Native Method) at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62) at java.base/jdk.internal.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) at java.base/java.lang.reflect.Method.invoke(Method.java:566) at org.junit.runners.model.FrameworkMethod$1.runReflectiveCall(FrameworkMethod.java:50) at org.junit.internal.runners.model.ReflectiveCallable.run(ReflectiveCallable.java:12) at org.junit.runners.model.FrameworkMethod.invokeExplosively(FrameworkMethod.java:47) at org.junit.internal.runners.statements.InvokeMethod.evaluate(InvokeMethod.java:17) at org.springframework.test.context.junit4.statements.RunBeforeTestExecutionCallbacks.evaluate(RunBeforeTestExecutionCallbacks.java:74) at org.springframework.test.context.junit4.statements.RunAfterTestExecutionCallbacks.evaluate(RunAfterTestExecutionCallbacks.java:84) at org.springframework.test.context.junit4.statements.RunBeforeTestMethodCallbacks.evaluate(RunBeforeTestMethodCallbacks.java:75) at org.springframework.test.context.junit4.statements.RunAfterTestMethodCallbacks.evaluate(RunAfterTestMethodCallbacks.java:86) at org.springframework.test.context.junit4.statements.SpringRepeat.evaluate(SpringRepeat.java:84) at org.junit.runners.ParentRunner.runLeaf(ParentRunner.java:325) at org.springframework.test.context.junit4.SpringJUnit4ClassRunner.runChild(SpringJUnit4ClassRunner.java:251) at org.springframework.test.context.junit4.SpringJUnit4ClassRunner.runChild(SpringJUnit4ClassRunner.java:97) at org.junit.runners.ParentRunner$3.run(ParentRunner.java:290) at org.junit.runners.ParentRunner$1.schedule(ParentRunner.java:71) at org.junit.runners.ParentRunner.runChildren(ParentRunner.java:288) at org.junit.runners.ParentRunner.access$000(ParentRunner.java:58) at org.junit.runners.ParentRunner$2.evaluate(ParentRunner.java:268) at org.springframework.test.context.junit4.statements.RunBeforeTestClassCallbacks.evaluate(RunBeforeTestClassCallbacks.java:61) at org.springframework.test.context.junit4.statements.RunAfterTestClassCallbacks.evaluate(RunAfterTestClassCallbacks.java:70) at org.junit.runners.ParentRunner.run(ParentRunner.java:363) at org.springframework.test.context.junit4.SpringJUnit4ClassRunner.run(SpringJUnit4ClassRunner.java:190) at org.junit.runner.JUnitCore.run(JUnitCore.java:137) at com.intellij.junit4.JUnit4IdeaTestRunner.startRunnerWithArgs(JUnit4IdeaTestRunner.java:68) at com.intellij.rt.execution.junit.IdeaTestRunner$Repeater.startRunnerWithArgs(IdeaTestRunner.java:47) at com.intellij.rt.execution.junit.JUnitStarter.prepareStreamsAndStart(JUnitStarter.java:242) at com.intellij.rt.execution.junit.JUnitStarter.main(JUnitStarter.java:70) Caused by: com.nsa.charitystarter.controllers.exceptions.MissingResourceException: No matching charity at com.nsa.charitystarter.controllers.CharityProfile.getCharityProfile(CharityProfile.java:38)

The missing resource exception is defined as follows...

public class MissingResourceException extends RuntimeException {
    protected String returnUrl;

    public MissingResourceException(String msg, String returnUrl) {
        super(msg);
        this.returnUrl = returnUrl;
    }

    public MissingResourceException(String msg) {
        this(msg, "/");
    }

    public MissingResourceException() {
        this("Missing Resource", "/");
    }
}

It gets used as follows...

@ControllerAdvice(annotations = RestController.class)
public class RestResponseEntityExceptionHandler extends ResponseEntityExceptionHandler {
    @ExceptionHandler(MissingResourceException.class)
    protected ResponseEntity<Object> handleMissingResource(RuntimeException ex,
                                                           WebRequest request) {
        String bodyOfResponse = ex.getMessage();
        return handleExceptionInternal(ex, bodyOfResponse,
                new HttpHeaders(), HttpStatus.NOT_FOUND, request);
    }

    @ExceptionHandler(NonUniqueResourceException.class)
    protected ResponseEntity<Object> handleNonUniqueResource(RuntimeException ex,
                                                             WebRequest request) {
        String bodyOfResponse = ex.getMessage();
        return handleExceptionInternal(ex, bodyOfResponse,
                new HttpHeaders(), HttpStatus.CONFLICT, request);
    }
}

Not sure why the error is occuring. Any advice on how this can be fixed?