SpringBoot Properties not available when using SpringBootTest.UseMainMethod.ALWAYS

When using useMainMethod = SpringBootTest.UseMainMethod.NEVER, properties are passed into the Environment, so this test passes:

@SpringBootTest(properties = "test=1", useMainMethod = SpringBootTest.UseMainMethod.NEVER)
class UseMainMethodsApplicationTests {

    @Test
    void contextLoads(@Autowired Environment environment) {
        assertThat(environment.getProperty("test")).isEqualTo("1");
    }

}

When setting useMainMethod = SpringBootTest.UseMainMethod.WHEN_AVAILABLE or useMainMethod = SpringBootTest.UseMainMethod.ALWAYS, the properties passed via properties attribute are not in the environment. This test fails:

@SpringBootTest(properties = "test=1", useMainMethod = SpringBootTest.UseMainMethod.ALWAYS)
class UseMainMethodsApplicationTests {

    @Test
    void contextLoads(@Autowired Environment environment) {
        assertThat(environment.getProperty("test")).isEqualTo("1");
    }

}

expected: "1"
 but was: null

If this is intended, we should add a note to the docs.

Observed in Spring Boot 3.0.0 RC1.