@Override
    public IndexSpecs getIndexSpecs(Scheme scheme) {
        var keySpace = getKeySpace(scheme);
        var result = extensionIndexSpecs.get(keySpace);
        if (result == null) {
            throw new IllegalArgumentException(
                "No index specs found for extension type: " + scheme.groupVersionKind()
                    + ", make sure you have called indexFor() before calling getIndexSpecs()");

        }
        return result;
    }
@Test
    void getIndexSpecs() {
        assertThatThrownBy(() -> indexSpecRegistry.getIndexSpecs(scheme))
            .isInstanceOf(IllegalArgumentException.class)
            .hasMessageContaining("No index specs found for extension type: ");

        indexSpecRegistry.indexFor(scheme);
        var specs = indexSpecRegistry.getIndexSpecs(scheme);
        assertThat(specs).isNotNull();
    }