Update documentation

test/test_refcount.c

@@ -21,9 +21,7 @@ A *make_a(RefcountContext *c, int n, const char *s) {
 
 bool held_refs_callback(void *a_raw, RefcountList **out, void *ignored) {
     A *a = a_raw;
-    if (a->next) {
-        *out = refcount_list_push_full(*out, a->next, &COUNTING_ALLOCATOR);
-    }
+    *out = refcount_list_push_full(*out, a->next, &COUNTING_ALLOCATOR);
     return true;
 }
 
@@ -73,11 +71,47 @@ int main(int argc, const char **argv) {
     a->next = refcount_context_ref(c, a);
     assert(refcount_context_num_refs(c, a) == 1);
 
+    refcount_context_unref(c, a);
+
+    a = NULL;
+    for (char i = 'a'; i <= 'z'; ++i) {
+        A *na = make_a(c, i, "");
+        na->next = refcount_context_ref(c, a);
+        a = na;
+    }
+    assert(refcount_context_num_refs(c, a) == 0);
+
+    refcount_context_unref(c, a);
+
+    A *first = NULL;
+    a = NULL;
+    for (char i = 'a'; i <= 'z'; ++i) {
+        A *na = make_a(c, i, "");
+        if (!first) {
+            first = na;
+        }
+        na->next = refcount_context_ref(c, a);
+        a = na;
+    }
+    assert(refcount_context_num_refs(c, a) == 0);
+    first->next = refcount_context_ref(c, a);
+    a = first;
+    assert(refcount_context_num_refs(c, a) == 1);
+
     refcount_context_ref(c, a);
     refcount_context_unref(c, a);
     assert(refcount_context_num_refs(c, a) == 1);
 
-    refcount_context_garbage_collect(c);
+    a = NULL;
+    for (char i = 'a'; i <= 'z'; ++i) {
+        A *na = make_a(c, i, "");
+        na->next = refcount_context_ref(c, a);
+        a = na;
+    }
+    assert(refcount_context_num_refs(c, a) == 0);
+    refcount_context_unref(c, a);
+
+    assert(refcount_context_garbage_collect(c) == 26);
 
     refcount_context_destroy(c);