test: add null handling tests for dynamic array functions

src/test_dynamic_array.c

@@ -178,6 +178,74 @@ void test_array_looping(void) {
 }
 
 
+/* --- array_get_header branch: NULL arr → returns NULL --- */
+void test_array_get_header_on_null_returns_null(void) {
+    int *arr = NULL;
+    TEST_ASSERT_NULL(array_get_header(arr));
+}
+
+
+/* --- array_destroy branch: NULL arr → no-op, does not crash --- */
+void test_array_destroy_on_null_is_noop(void) {
+    int *arr = NULL;
+    array_destroy(arr);
+    TEST_ASSERT_NULL(arr);
+}
+
+
+/* --- array_push_value branch: NULL arr → auto-creates the array --- */
+void test_array_push_value_on_null_auto_creates(void) {
+    int *arr = NULL;
+    array_push_value(arr, 7);
+    TEST_ASSERT_NOT_NULL(arr);
+    TEST_ASSERT_EQUAL(7, arr[0]);
+    TEST_ASSERT_EQUAL(1, array_get_header(arr)->size);
+    array_destroy(arr);
+}
+
+
+/* --- array_pop branch: NULL arr → no-op, does not crash --- */
+void test_array_pop_on_null_is_noop(void) {
+    int *arr = NULL;
+    array_pop(arr);
+    TEST_ASSERT_NULL(arr);
+}
+
+
+/* --- array_size branch: NULL arr → 0 --- */
+void test_array_size_on_null_returns_zero(void) {
+    int *arr = NULL;
+    TEST_ASSERT_EQUAL(0, array_size(arr));
+}
+
+
+/* --- array_size branch: non-NULL arr → current size --- */
+void test_array_size_returns_current_size(void) {
+    int *arr = NULL;
+    array_create(arr);
+    array_push_value(arr, 1);
+    array_push_value(arr, 2);
+    TEST_ASSERT_EQUAL(2, array_size(arr));
+    array_destroy(arr);
+}
+
+
+/* --- array_capacity branch: NULL arr → 0 --- */
+void test_array_capacity_on_null_returns_zero(void) {
+    int *arr = NULL;
+    TEST_ASSERT_EQUAL(0, array_capacity(arr));
+}
+
+
+/* --- array_capacity branch: non-NULL arr → current capacity --- */
+void test_array_capacity_returns_current_capacity(void) {
+    int *arr = NULL;
+    array_create(arr);
+    TEST_ASSERT_EQUAL(DYNAMIC_ARRAY_DEFAULT_ARRAY_SIZE, array_capacity(arr));
+    array_destroy(arr);
+}
+
+
 int main(void)
 {
     UNITY_BEGIN();
@@ -195,5 +263,14 @@ int main(void)
     RUN_TEST(test_array_values_correct_after_growth);
     RUN_TEST(test_array_looping);
 
+    RUN_TEST(test_array_get_header_on_null_returns_null);
+    RUN_TEST(test_array_destroy_on_null_is_noop);
+    RUN_TEST(test_array_push_value_on_null_auto_creates);
+    RUN_TEST(test_array_pop_on_null_is_noop);
+    RUN_TEST(test_array_size_on_null_returns_zero);
+    RUN_TEST(test_array_size_returns_current_size);
+    RUN_TEST(test_array_capacity_on_null_returns_zero);
+    RUN_TEST(test_array_capacity_returns_current_capacity);
+
     return UNITY_END();
 }