From ba8728320cbda4ecb95ffe9d795f0121524e923f Mon Sep 17 00:00:00 2001
From: "Douglas B. Rumbaugh" <doug@douglasrumbaugh.com>
Date: Sun, 2 Nov 2025 16:52:27 -0500
Subject: liballoc_tests: Added coalesce testing for free list

---
 tests/liballoc_tests.c | 53 ++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 53 insertions(+)

diff --git a/tests/liballoc_tests.c b/tests/liballoc_tests.c
index fed6080..ad45636 100644
--- a/tests/liballoc_tests.c
+++ b/tests/liballoc_tests.c
@@ -121,6 +121,57 @@ START_TEST(free_list_reuse) {
     release(new_memory);
   }
 }
+END_TEST
+
+START_TEST(free_list_coalesce_forward) {
+  size_t size =ALIGNMENT*3;
+  const size_t n = 100;
+  void *ptrs[n];
+
+  for (size_t i=0; i<n; i++) {
+    ptrs[i] = allocate(size);
+  }
+
+  /* 
+   * release memory in forward order. Each release should be
+   * coalesced, so there's only ever one free block
+   */  
+   size_t cnt = 0;
+   for(size_t i=0; i<n; i++) {
+     release(ptrs[i]);
+     cnt++;
+     free_nd *fl_head = free_list_head();
+     ck_assert_ptr_null(fl_head->next);
+     ck_assert_int_eq(fl_head->size, (cnt)*size + (cnt-1)*sizeof(header));
+   }
+}
+END_TEST
+
+
+START_TEST(free_list_coalesce_backward) {
+  size_t size =ALIGNMENT*3;
+  const size_t n = 100;
+  void *ptrs[n];
+
+  for (size_t i=0; i<n; i++) {
+    ptrs[i] = allocate(size);
+  }
+
+  /* 
+   * release memory in reverse order. Each release should be
+   * coalesced, so there's only ever one free block
+   */  
+   size_t cnt = 0;
+   for(ssize_t i=n-1; i>=0; i--) {
+     release(ptrs[i]);
+     cnt++;
+     free_nd *fl_head = free_list_head();
+     ck_assert_ptr_null(fl_head->next);
+     ck_assert_int_eq(fl_head->size, (cnt)*size + (cnt-1)*sizeof(header));
+   }
+}
+END_TEST
+
 
 
 Suite *liballoc_suite(void) {
@@ -136,6 +187,8 @@ Suite *liballoc_suite(void) {
   tcase_add_test(unit, basic_release);
   tcase_add_test(unit, release_null);
   tcase_add_test(unit, free_list_reuse);
+  tcase_add_test(unit, free_list_coalesce_forward);
+  tcase_add_test(unit, free_list_coalesce_backward);
 
   suite_add_tcase(s, unit);
   return s;
-- 
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