First test added, changed signature for using pointers beacause i forgot you can't actually change a parameter because c copies everything, stupid from me to forget that

test/CMakeLists.txt

@@ -1,10 +1,10 @@
 find_package(cmocka REQUIRED)
 
-add_executable(test_parser test_parser.c)
+add_executable(test_nodeArray test_ASTNodeArray.c)
 
-target_link_libraries(test_parser
+target_link_libraries(test_nodeArray
     calculator_lib
     cmocka::cmocka
 )
 
-add_test(NAME parser_tests COMMAND test_parser)
+add_test(NAME nodeArray_tests COMMAND test_nodeArray)

test/test_ASTNodeArray.c

@@ -0,0 +1,46 @@
+#include "lexer.h"
+#include <stdarg.h>
+#include <stdbool.h>
+#include <stddef.h>
+#include <stdint.h>
+#include <setjmp.h>
+#include <cmocka.h>
+
+static void test_array_push(void **state) {
+    (void) state;
+
+    ASTNodeArray arr = ASTNodeArray_init(2);
+    ASTNode node1 = {
+        .type = NODE_NUMBER,
+        .operator = { .number = 90 }
+    };
+
+    ASTNode node2 = {
+        .type = NODE_NUMBER,
+        .operator = { .number = 80 }
+    };
+
+    ASTNode node3 = {
+        .type = NODE_NUMBER,
+        .operator = { .number = 70 }
+    };
+
+    assert_int_equal(ASTNodeArray_push(&arr, node1), ARRAY_OK);
+    assert_int_equal(ASTNodeArray_len(&arr), 1);
+
+    assert_int_equal(ASTNodeArray_push(&arr, node2), ARRAY_OK);
+    assert_int_equal(ASTNodeArray_len(&arr), 2);
+
+    assert_int_equal(ASTNodeArray_push(&arr, node3), ARRAY_OK);
+    assert_int_equal(ASTNodeArray_len(&arr), 3);
+}
+
+
+
+int main(void) {
+    const struct CMUnitTest tests[] = {
+        cmocka_unit_test(test_array_push),
+    };
+
+    return cmocka_run_group_tests(tests, NULL, NULL);
+}