Update test/subtraction/subtraction.c

test/subtraction/subtraction

@@ -1 +0,0 @@
-

test/subtraction/subtraction.c

@@ -0,0 +1,8 @@
+#include "unity.h"
+#include "subtraction.h"
+
+void test_subtraction() {
+    TEST_ASSERT_EQUAL_INT(1, subtract(3, 2));
+    TEST_ASSERT_EQUAL_INT(5, subtract(2, -3));
+    TEST_ASSERT_EQUAL_INT(0, subtract(0, 0));
+}