@Test
    void duplicateMappingsWithRegex() {
        // Ensure that 3 routers are created first really.
        assertThat(Routers.routers(ImmutableList.of(Route.builder().path("/foo/:bar").build(),
                                                    Route.builder().regex("not-trie-compatible").build(),
                                                    Route.builder().path("/bar/:baz").build()),
                                   null, null, Function.identity(), REJECT, false)).hasSize(3);

        testDuplicateRoutes(Route.builder().path("/foo/:bar").build(),
                            Route.builder().regex("not-trie-compatible").build(),
                            Route.builder().path("/foo/:qux").build());
    }
Should detect the duplicates even if the mappings are split into more than one router.
core/src/test/java/com/linecorp/armeria/server/RouterTest.java