spring-boot-demo/problem-details/src/test/java/com/ankurm/problems/AdviceContractTest.java

package com.ankurm.problems;

import org.junit.jupiter.api.Test;

import org.springframework.boot.test.context.SpringBootTest;
import org.springframework.boot.test.web.server.LocalServerPort;
import org.springframework.test.context.ActiveProfiles;

import static org.assertj.core.api.Assertions.assertThat;

/**
 * The contract of the recommended setup (profiles advice + errors): every failure, including the
 * ones produced outside Spring MVC, is application/problem+json with the right status.
 */
@SpringBootTest(webEnvironment = SpringBootTest.WebEnvironment.RANDOM_PORT)
@ActiveProfiles({"advice", "errors"})
class AdviceContractTest {

    private static final String PROBLEM = "application/problem+json";

    @LocalServerPort
    int port;

    @Test
    void domainExceptionIs404WithStableType() throws Exception {
        Http.Response r = Http.get(port, "/orders/999");
        assertThat(r.status()).isEqualTo(404);
        assertThat(r.contentType()).isEqualTo(PROBLEM);
        assertThat(r.body()).contains("\"type\":\"https://ankurm.com/problems/order-not-found\"")
                .contains("\"orderId\":999")
                .contains("\"instance\":\"/orders/999\"");
    }

    @Test
    void validationListsEveryViolationWithAPointer() throws Exception {
        Http.Response r = Http.send(port, "POST", "/orders", "{\"sku\":\"\",\"quantity\":0,\"customerEmail\":\"nope\"}");
        assertThat(r.status()).isEqualTo(400);
        assertThat(r.contentType()).isEqualTo(PROBLEM);
        // Order of the three is not stable between runs - assert membership, not position.
        assertThat(r.body()).contains("\"pointer\":\"#/sku\"", "\"pointer\":\"#/quantity\"",
                "\"pointer\":\"#/customerEmail\"");
    }

    @Test
    void unexpectedExceptionDoesNotLeakItsMessage() throws Exception {
        Http.Response r = Http.get(port, "/orders/boom");
        assertThat(r.status()).isEqualTo(500);
        assertThat(r.contentType()).isEqualTo(PROBLEM);
        assertThat(r.body()).contains("\"errorId\":").doesNotContain("jdbc:").doesNotContain("orders_rw");
    }

    @Test
    void filterExceptionReachesTheErrorControllerNotTheAdvice() throws Exception {
        Http.Response r = Http.get(port, "/orders/1", "X-Tenant", "BAD!");
        assertThat(r.status()).isEqualTo(500);
        assertThat(r.contentType()).isEqualTo(PROBLEM);
        assertThat(r.body()).doesNotContain("X-Tenant").doesNotContain("errorId");
    }

    @Test
    void securityResponsesAreProblemsToo() throws Exception {
        Http.Response anonymous = Http.get(port, "/admin/orders");
        assertThat(anonymous.status()).isEqualTo(401);
        assertThat(anonymous.contentType()).isEqualTo(PROBLEM);
        assertThat(anonymous.headers().firstValue("WWW-Authenticate")).hasValue("Basic realm=\"orders\"");

        Http.Response user = Http.get(port, "/admin/orders", "Authorization", Http.basic("user", "user"));
        assertThat(user.status()).isEqualTo(403);
        assertThat(user.contentType()).isEqualTo(PROBLEM);
    }

    @Test
    void anAcceptOfApplicationXmlStillGetsJson() throws Exception {
        // application/xml is not compatible with application/problem+xml, so the error falls back
        // to problem+json - while a successful response to the same Accept header is XML.
        assertThat(Http.get(port, "/orders/1", "Accept", "application/xml").contentType())
                .startsWith("application/xml");
        assertThat(Http.get(port, "/orders/999", "Accept", "application/xml").contentType())
                .isEqualTo(PROBLEM);
        assertThat(Http.get(port, "/orders/999", "Accept", "application/problem+xml").contentType())
                .isEqualTo("application/problem+xml");
    }

    @Test
    void anUnsatisfiableAcceptDoesNotTurnTheErrorInto406() throws Exception {
        Http.Response r = Http.get(port, "/orders/999", "Accept", "image/png");
        assertThat(r.status()).isEqualTo(404);
        assertThat(r.contentType()).isEqualTo(PROBLEM);
    }

    @Test
    void messageSourceOverridesTitleAndDetailPerLocale() throws Exception {
        String body = "{\"sku\":\"SKU-2\",\"quantity\":3,\"customerEmail\":\"[email protected]\"}";
        assertThat(Http.send(port, "POST", "/orders", body).body())
                .contains("\"title\":\"Out of stock\"")
                .contains("\"detail\":\"Only 0 unit(s) of SKU-2 are available.\"");
        assertThat(Http.send(port, "POST", "/orders", body, "Accept-Language", "de").body())
                .contains("\"title\":\"Nicht vorrätig\"");
    }
}