`@SpringBatchTest` with JUnit `@Nested` triggers new test context creation

[scordio]

Bug description
When using @SpringBatchTest on a test class enclosing a @Nested class, two separate Spring test contexts are created, one to execute the test methods in the outer class and another for the ones in the inner class.

Environment
Spring Batch 5.2.1 (originally detected on Spring Batch 4.3.10)

Steps to reproduce

import org.junit.jupiter.api.Nested;
import org.junit.jupiter.api.Test;
import org.springframework.batch.test.context.SpringBatchTest;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.context.ApplicationContext;
import org.springframework.test.context.junit.jupiter.SpringJUnitConfig;

import static org.junit.jupiter.api.Assertions.assertSame;

@SpringJUnitConfig
@SpringBatchTest
class WithAnnotationTest {

  @Autowired
  ApplicationContext context;

  @Nested
  class Inner {

    @Autowired
    ApplicationContext context;

    @Test
    void test() {
      assertSame(WithAnnotationTest.this.context, context); // should succeed but fails
    }

  }

}

Expected behavior
A single test context should be available for both the outer and the inner class, like in the following example:

import org.junit.jupiter.api.Nested;
import org.junit.jupiter.api.Test;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.context.ApplicationContext;
import org.springframework.test.context.junit.jupiter.SpringJUnitConfig;

import static org.junit.jupiter.api.Assertions.assertSame;

@SpringJUnitConfig
class WithoutAnnotationTest {

  @Autowired
  ApplicationContext context;

  @Nested
  class Inner {

    @Autowired
    ApplicationContext context;

    @Test
    void test() {
      assertSame(WithoutAnnotationTest.this.context, context); // succeeds
    }

  }

}

Workaround
Applying @SpringBatchTest also on the inner class prevents the creation of the additional test context:

import org.junit.jupiter.api.Nested;
import org.junit.jupiter.api.Test;
import org.springframework.batch.test.context.SpringBatchTest;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.context.ApplicationContext;
import org.springframework.test.context.junit.jupiter.SpringJUnitConfig;

import static org.junit.jupiter.api.Assertions.assertSame;

@SpringJUnitConfig
@SpringBatchTest
class WithDoubleAnnotationTest {

  @Autowired
  ApplicationContext context;

  @Nested
  @SpringBatchTest
  class Inner {

    @Autowired
    ApplicationContext context;

    @Test
    void test() {
      assertSame(WithDoubleAnnotationTest.this.context, context); // succeeds
    }

  }

}

Minimal Complete Reproducible example
https://github.com/scordio/spring-boot-playground/tree/spring-batch-4738-reproducer

[fmbenhassine]

Resolved with #4739