Add minimal abstract machine module

tests/CMakeLists.txt

@@ -9,6 +9,7 @@ function(add_test_suites)
 endfunction()
 
 add_test_suites(
+  am_tests.c
   store_tests.c
   token_tests.c
 )

tests/am_tests.c

@@ -0,0 +1,30 @@
+#include "am.h"
+#include "unity.h"
+
+static am_t am;
+
+void setUp(void)
+{
+	am_init(&am);
+}
+
+void tearDown(void)
+{
+}
+
+static void test_expr_value_restored_after_push_modify_pop(void)
+{
+	expr_t a, b;
+	am.expr = &a;
+	am_push(&am);
+	am.expr = &b;
+	am_pop(&am);
+	TEST_ASSERT_EQUAL(&a, am.expr);
+}
+
+int main(void)
+{
+	UNITY_BEGIN();
+	RUN_TEST(test_expr_value_restored_after_push_modify_pop);
+	return UNITY_END();
+}