Convert min stack to near constant time algorithm

1 files changed, 85 insertions, 3 deletions

diff --git a/src/01/06/min_stack_test.c b/src/01/06/min_stack_test.c
index b892d5f..c796dca 100644
--- a/src/01/06/min_stack_test.c
+++ b/src/01/06/min_stack_test.c
@@ -15,6 +15,74 @@ Ensure(MinStack, when_empty) {
   free(stack);
 }
 
+Ensure(MinStack, when_empty_it_has_a_size_of_zero) {
+  Stack *stack = initialize();
+
+  assert_that(size(stack), is_equal_to(0));
+
+  free(stack);
+}
+
+Ensure(MinStack, when_empty_it_has_a_min_of_null) {
+  Stack *stack = initialize();
+
+  assert_that(min(stack), is_equal_to(NULL));
+
+  free(stack);
+}
+
+Ensure(MinStack, when_a_single_item_is_on_the_stack_it_has_a_size_of_one) {
+  Stack *stack = initialize();
+
+  push(stack, 1);
+
+  assert_that(size(stack), is_equal_to(1));
+
+  free(stack);
+}
+
+Ensure(MinStack, when_a_single_item_is_on_the_stack_it_is_the_min) {
+  Stack *stack = initialize();
+
+  push(stack, -100);
+
+  assert_that(min(stack), is_equal_to(-100));
+
+  free(stack);
+}
+
+Ensure(MinStack, when_a_single_item_is_on_the_stack_when_it_is_popped_off_it_returns_the_item) {
+  Stack *stack = initialize();
+
+  push(stack, 200);
+
+  assert_that(pop(stack), is_equal_to(200));
+
+  free(stack);
+}
+
+Ensure(MinStack, when_a_single_item_is_on_the_stack_when_it_is_popped_off_it_returns_a_size_of_zero) {
+  Stack *stack = initialize();
+
+  push(stack, 200);
+  pop(stack);
+
+  assert_that(size(stack), is_equal_to(0));
+
+  free(stack);
+}
+
+Ensure(MinStack, when_a_single_item_is_on_the_stack_when_it_is_popped_off_it_returns_a_min_of_null) {
+  Stack *stack = initialize();
+
+  push(stack, 200);
+  pop(stack);
+
+  assert_that(min(stack), is_equal_to(NULL));
+
+  free(stack);
+}
+
 Ensure(MinStack, when_pushing_a_single_integer) {
   Stack *stack = initialize();
 
@@ -33,18 +101,23 @@ Ensure(MinStack, when_pushing_multiple_integers_out_of_order) {
 
   push(stack, 2);
   push(stack, 3);
+  push(stack, 4);
   push(stack, 1);
 
-  assert_that(size(stack), is_equal_to(3));
+  assert_that(size(stack), is_equal_to(4));
   assert_that(min(stack), is_equal_to(1));
 
   assert_that(pop(stack), is_equal_to(1));
+  assert_that(size(stack), is_equal_to(3));
+  assert_that(min(stack), is_equal_to(2));
+
+  assert_that(pop(stack), is_equal_to(4));
   assert_that(size(stack), is_equal_to(2));
   assert_that(min(stack), is_equal_to(2));
 
   assert_that(pop(stack), is_equal_to(3));
   assert_that(size(stack), is_equal_to(1));
-  assert_that(min(stack), is_equal_to(3));
+  assert_that(min(stack), is_equal_to(2));
 
   assert_that(pop(stack), is_equal_to(2));
   assert_that(size(stack), is_equal_to(0));
@@ -83,7 +156,16 @@ Ensure(MinStack, when_pushing_duplicate_values_on_to_the_stack) {
 TestSuite *min_stack_tests() {
   TestSuite *suite = create_test_suite();
 
-  add_test_with_context(suite, MinStack, when_empty);
+  add_test_with_context(suite, MinStack, when_empty_it_has_a_size_of_zero);
+  add_test_with_context(suite, MinStack, when_empty_it_has_a_min_of_null);
+
+  add_test_with_context(suite, MinStack, when_a_single_item_is_on_the_stack_it_has_a_size_of_one);
+  add_test_with_context(suite, MinStack, when_a_single_item_is_on_the_stack_it_is_the_min);
+
+  add_test_with_context(suite, MinStack, when_a_single_item_is_on_the_stack_when_it_is_popped_off_it_returns_the_item);
+  add_test_with_context(suite, MinStack, when_a_single_item_is_on_the_stack_when_it_is_popped_off_it_returns_a_size_of_zero);
+  add_test_with_context(suite, MinStack, when_a_single_item_is_on_the_stack_when_it_is_popped_off_it_returns_a_min_of_null);
+
   add_test_with_context(suite, MinStack, when_pushing_a_single_integer);
   add_test_with_context(suite, MinStack, when_pushing_multiple_integers_out_of_order);
   return suite;