What is conditional test execution in JUnit 6 and what built-in conditions are available?

import org.junit.jupiter.api.condition.*;

class ConditionalTests {

    @Test
    @EnabledOnOs(OS.LINUX)
    void linuxOnlyTest() { ... }

    @Test
    @DisabledOnOs({OS.WINDOWS, OS.MAC})
    void notOnWindowsOrMac() { ... }

    @Test
    @EnabledOnJre(JRE.JAVA_21)
    void java21Feature() { ... }

    @Test
    @EnabledForJreRange(min = JRE.JAVA_17, max = JRE.JAVA_21)
    void java17to21Only() { ... }

    @Test
    @EnabledIfEnvironmentVariable(named = "ENV", matches = "CI")
    void ciOnlyTest() { ... }

    @Test
    @EnabledIfSystemProperty(named = "db.available", matches = "true")
    void databaseTest() { ... }

    // @EnabledIf: call a custom static method
    @Test
    @EnabledIf("isWeekend")
    void weekendTest() { ... }

    static boolean isWeekend() {
        DayOfWeek day = LocalDate.now().getDayOfWeek();
        return day == DayOfWeek.SATURDAY || day == DayOfWeek.SUNDAY;
    }
}