more tests

hostnames_allocator/tests/ranged_number_allocator_tests.rs

@@ -96,6 +96,13 @@ fn allocate_combines_two_adjacent_ranges_starting_with_one() {
     check_allocator(allocator, &[(1, 15)]);
 }
 
+#[test]
+fn allocate_combines_two_adjacent_ranges_starting_with_one_extra() {
+    let mut allocator = create_allocator(&[(1, 5), (7, 15), (20, 30)]);
+    assert_eq!(allocator.allocate(), 6);
+    check_allocator(allocator, &[(1, 15), (20, 30)]);
+}
+
 #[test]
 fn allocate_adds_value_for_range_starting_with_two() {
     let mut allocator = create_allocator(&[(2, 10)]);
@@ -103,6 +110,13 @@ fn allocate_adds_value_for_range_starting_with_two() {
     check_allocator(allocator, &[(1, 10)]);
 }
 
+#[test]
+fn allocate_adds_value_for_range_starting_with_two_extra() {
+    let mut allocator = create_allocator(&[(2, 10), (20, 30)]);
+    assert_eq!(allocator.allocate(), 1);
+    check_allocator(allocator, &[(1, 10), (20, 30)]);
+}
+
 #[test]
 fn allocate_adds_value_for_range_starting_with_ten() {
     let mut allocator = create_allocator(&[(10, 20)]);