gcd : Added unit test and Makefile target

gcd/Makefile

@@ -11,6 +11,10 @@ bin/gcd: src/gcd.cpp | check-cxx-works bin
 	@echo Compiling $<
 	@${CXX} ${CFLAGS} $^ -o $@
 
+bin/gcd_test: src/gcd_test.cpp | check-cxx-works bin
+	@echo Compiling $^
+	@${CXX} ${CFLAGS} $^ -o $@
+
 .PHONY: install
 install: bin/gcd
 	@cp -v $^ /usr/bin
@@ -19,6 +23,10 @@ install: bin/gcd
 uninstall: /usr/bin/gcd
 	@rm -v $^
 
+.PHONY: test
+test: bin/gcd_test
+	@./$^
+
 .PHONY: clean
 clean:
 	@rm -rfv bin

gcd/src/gcd.cpp

@@ -4,15 +4,7 @@
 #include <cstring>
 #include <limits.h>
 #include <stdint.h>
-
-/**
- * @brief Calculate the greatest common divisor (GCD)
- *
- * @param a First integer
- * @param b Second integer
- * @return greatest common divisor between a and b
- */
-constexpr int64_t gcd(const int64_t& a, const int64_t& b) noexcept { return a == 0 ? b : gcd(b % a, a); }
+#include "gcd.hpp"
 
 /**
  * @brief Convert a given string to a 64 bit integer
@@ -54,8 +46,7 @@ int32_t main(const int32_t argc, const char* const* argv) noexcept {
 		return EXIT_FAILURE;
 	}
 	int64_t a, b;
-	if(sstrtoll(argv[1], a) == EXIT_FAILURE) return EXIT_FAILURE;
-	if(sstrtoll(argv[2], b) == EXIT_FAILURE) return EXIT_FAILURE;
+	if(sstrtoll(argv[1], a) == EXIT_FAILURE || sstrtoll(argv[2], b) == EXIT_FAILURE) return EXIT_FAILURE;
 
 	const int64_t hcf = gcd(std::abs(a), std::abs(b));
 	printf("Common factor = %ld\nResult = %ld/%ld\n", hcf, a / hcf, b / hcf);

gcd/src/gcd.hpp

@@ -0,0 +1,10 @@
+#include <stdint.h>
+
+/**
+ * @brief Calculate the greatest common divisor (GCD)
+ *
+ * @param a First integer
+ * @param b Second integer
+ * @return greatest common divisor between a and b
+ */
+constexpr uint64_t gcd(const uint64_t a, const uint64_t b) noexcept { return a == 0 ? b : gcd(b % a, a); }

gcd/src/gcd_test.cpp

@@ -0,0 +1,37 @@
+#include <iostream>
+#include <cassert>
+#include "gcd.hpp"
+
+/**
+ * @brief Test if a given result is equal of the expected one and log result
+ *
+ * @param name of the unit test
+ * @param expected result of the function call
+ * @param result of the function
+ */
+static void Assert(const char* const name, const uint64_t expected, const uint64_t result) noexcept {
+	if(expected != result){
+		std::cerr << "For test named " << name << " Expected '" << expected << "' but got '" << result << "' instead\n";
+	}
+}
+
+/**
+ * @brief Test suite for the gcd output
+ */
+void gcd_test(void) noexcept {
+	Assert("gcd null LR",      0,      gcd(0,      0));
+	Assert("gcd null L",       196883, gcd(196883, 0));
+	Assert("gcd null R",       196883, gcd(0,      196883));
+	Assert("gcd self",         196883, gcd(196883, 196883));
+	Assert("gcd Full HD",      120,    gcd(1920,   1080));
+	Assert("gcd monsterfel",   2773,   gcd(196883, 194110));
+	Assert("gcd monsterfel 2", 2773,   gcd(194110, 196883));
+	Assert("gcd monsterful",   4189,   gcd(196883, 192694));
+	Assert("gcd monsterful 2", 4189,   gcd(192694, 196883));
+}
+
+int32_t main(void){
+	setlocale(LC_NUMERIC, ""); // Allow proper number display
+	gcd_test();
+	return EXIT_SUCCESS;
+}