tests: Add unit tests for repeated_chars_iterator

tests/beman/iterator_interface/iterator_interface.test.cpp

@@ -43,6 +43,18 @@ TEST(IteratorTest, TestRepeatedChars) {
     ASSERT_EQ(result, "foofoof");
 }
 
+TEST(IteratorTest, TestDistance) {
+    repeated_chars_iterator first("foo", 3, 0); // 3 is the length of "foo", 0 is this iterator's position.
+    repeated_chars_iterator last("foo", 3, 3); // 3 is the length of "foo", 3 is this iterator's position.
+    ASSERT_EQ(std::distance(first, last), 3);
+}
+
+TEST(IteratorTest, TestLoop) {
+    repeated_chars_iterator first("foo", 3, 0); // 3 is the length of "foo", 0 is this iterator's position.
+    repeated_chars_iterator last("foo", 3, 3); // 3 is the length of "foo", 3 is this iterator's position.
+    ASSERT_EQ(std::next(first, 3), last);
+}
+
 template <typename Pred>
 struct filtered_int_iterator
     : ext_iterator_interface_compat<filtered_int_iterator<Pred>, std::forward_iterator_tag, int> {