Add test for toUSD function

tests/test_currencyExchange.c

@@ -0,0 +1,35 @@
+#ifdef TEST
+
+#include "unity.h"
+#include "currencyExchange.h"
+
+void setUp(void)
+{
+}
+
+void tearDown(void)
+{
+}
+
+void test_toUSD(void) {
+    int length = 5;
+    float euro[] = {34, 233, 400, 100, 45};
+    float expectedUSD[length];
+    float resultUSD[length];
+
+    for (int i = 0; i < length; i++) {
+        resultUSD[i] = toUSD(euro[i]);
+    }
+
+    for (int i = 0; i < length; i++) {
+        expectedUSD[i] = euro[i] * CURRENT_USD_RATE_OF_ONE_EURO;
+    }
+
+    for (int i = 0; i < length; i++) {
+        TEST_ASSERT_EQUAL_FLOAT(expectedUSD[i], resultUSD[i]);
+    }
+
+}
+
+
+#endif // TEST