test_lisp_api: added sys_test

test/test_lisp_api.c

@@ -141,6 +141,51 @@ void cons_test(void)
   TEST_PASSED();
 }
 
+void sys_test(void)
+{
+  sys_t sys = {0};
+  sys_init(&sys);
+  u64 old_memory_size = sys.memory.size;
+
+  // Creating integers doesn't affect memory size
+  (void)make_int(2000);
+  TEST(sys.memory.size == old_memory_size,
+       "Making integers doesn't affect system memory size");
+
+  // Creating symbols won't affect memory size, but does affect the symbol table
+  (void)intern(&sys, SV("hello world!", 12));
+  TEST(sys.memory.size == old_memory_size,
+       "Interning doesn't affect system memory size");
+  TEST(sys.symtable.count > 0, "Interning affects symbol table");
+
+  // Creating cons' do affect memory size
+  (void)cons(&sys, make_int(1), make_int(2));
+  TEST(sys.memory.size > 0, "Creating cons' affects memory size");
+  old_memory_size = sys.memory.size;
+
+  (void)cons(&sys, intern(&sys, SV("test", 4)), NIL);
+  TEST(sys.memory.size > old_memory_size,
+       "Creating cons' back to back affects memory size");
+  old_memory_size = sys.memory.size;
+
+  // Creating vectors does affect memory size
+  (void)make_vec(&sys, 8);
+  TEST(sys.memory.size > old_memory_size,
+       "Creating vectors (size 8) affects memory size");
+  old_memory_size = sys.memory.size;
+
+  (void)make_vec(&sys, 1000);
+  TEST(sys.memory.size > old_memory_size,
+       "Creating vectors (size 1000) affects memory size");
+  old_memory_size = sys.memory.size;
+
+  sys_free(&sys);
+  TEST(sys.memory.size == 0, "sys_free cleans up memory (shallow check)");
+  TEST(sys.symtable.count == 0, "sys_free cleans up symtable (shallow check)");
+
+  TEST_PASSED();
+}
+
 const test_suite_t LISP_API_SUITE = {
     .name = "Lisp API Tests",
     .tests =
@@ -150,8 +195,9 @@ const test_suite_t LISP_API_SUITE = {
             MAKE_TEST_FN(sym_fresh_test),
             MAKE_TEST_FN(sym_unique_test),
             MAKE_TEST_FN(cons_test),
+            MAKE_TEST_FN(sys_test),
         },
-    .size = 5,
+    .size = 6,
 };
 
 /* Copyright (C) 2026 Aryadev Chavali