unit tests for scrolling selector

tests/selector.cpp

@@ -171,6 +171,30 @@ TEST_CASE("SelectorTest") {
     CHECK(0 == notcurses_render(nc_));
     auto sel = ncselector_selected(ncs);
     REQUIRE(nullptr != sel);
+    CHECK(0 == strcmp(sel, items[0].option));
+    free(sel);
+    CHECK(0 == notcurses_render(nc_));
+    ncselector_nextitem(ncs, &sel);
+    REQUIRE(nullptr != sel);
+    CHECK(0 == strcmp(sel, items[1].option));
+    free(sel);
+    CHECK(0 == notcurses_render(nc_));
+    ncselector_previtem(ncs, &sel);
+    REQUIRE(nullptr != sel);
+    CHECK(0 == strcmp(sel, items[0].option));
+    free(sel);
+    CHECK(0 == notcurses_render(nc_));
+    // wrap around from the top to bottom...
+    ncselector_previtem(ncs, &sel);
+    REQUIRE(nullptr != sel);
+    CHECK(0 == strcmp(sel, items[2].option));
+    free(sel);
+    CHECK(0 == notcurses_render(nc_));
+    // ...and back to the top
+    ncselector_nextitem(ncs, &sel);
+    REQUIRE(nullptr != sel);
+    CHECK(0 == strcmp(sel, items[0].option));
+    free(sel);
     struct ncplane* ncsp = ncselector_plane(ncs);
     REQUIRE(nullptr != ncsp);
     int dimy, dimx;
@@ -193,6 +217,31 @@ TEST_CASE("SelectorTest") {
     struct ncselector* ncs = ncselector_create(notcurses_stdplane(nc_), 0, 0, &opts);
     REQUIRE(nullptr != ncs);
     CHECK(0 == notcurses_render(nc_));
+    auto sel = ncselector_selected(ncs);
+    CHECK(0 == strcmp(sel, items[0].option));
+    free(sel);
+    CHECK(0 == notcurses_render(nc_));
+    ncselector_nextitem(ncs, &sel);
+    REQUIRE(nullptr != sel);
+    CHECK(0 == strcmp(sel, items[1].option));
+    free(sel);
+    CHECK(0 == notcurses_render(nc_));
+    ncselector_previtem(ncs, &sel);
+    REQUIRE(nullptr != sel);
+    CHECK(0 == strcmp(sel, items[0].option));
+    free(sel);
+    CHECK(0 == notcurses_render(nc_));
+    // wrap around from the top to bottom...
+    ncselector_previtem(ncs, &sel);
+    REQUIRE(nullptr != sel);
+    CHECK(0 == strcmp(sel, items[2].option));
+    free(sel);
+    CHECK(0 == notcurses_render(nc_));
+    // ...and back to the top
+    ncselector_nextitem(ncs, &sel);
+    REQUIRE(nullptr != sel);
+    CHECK(0 == strcmp(sel, items[0].option));
+    free(sel);
     struct ncplane* ncsp = ncselector_plane(ncs);
     REQUIRE(nullptr != ncsp);
     int dimy, dimx;