[set] Add tests for inverted set range iteration

src/test-set.cc

@@ -107,5 +107,34 @@ main (int argc, char **argv)
     assert (v2.get_population () == 3);
   }
 
+  /* Test inverted sets. */
+  {
+    hb_set_t s;
+    s.invert();
+    s.del (5);
+
+    hb_codepoint_t start = HB_SET_VALUE_INVALID, last = HB_SET_VALUE_INVALID;
+    assert (s.next_range (&start, &last));
+    assert (start == 0);
+    assert (last == 4);
+    assert (s.next_range (&start, &last));
+    assert (start == 6);
+    assert (last == HB_SET_VALUE_INVALID - 1);
+    assert (!s.next_range (&start, &last));
+
+    start = HB_SET_VALUE_INVALID;
+    last = HB_SET_VALUE_INVALID;
+    assert (s.previous_range (&start, &last));
+    assert (start == 6);
+    assert (last == HB_SET_VALUE_INVALID - 1);
+    assert (s.previous_range (&start, &last));
+    assert (start == 0);
+    assert (last == 4);
+    assert (!s.previous_range (&start, &last));
+
+    /* Inverted set returns true for invalid value. */
+    assert (s.has (HB_SET_VALUE_INVALID));
+  }
+
   return 0;
 }