testing: addition base case 0+0=0

test/test_addition.c

@@ -75,4 +75,14 @@ void test_addition_full_adder_completesumwithcarry(void)
     TEST_ASSERT_EQUAL_INT(expectedcarry[4], carryresult[4]);
 }
 
+void test_addition_addition_basecasezeropluszeroequalzero(void)
+{
+    int result;
+    int expected = 0;
+
+    result = addition(0, 0);
+
+    TEST_ASSERT_EQUAL_INT(expected, result);
+}
+
 #endif // TEST