Unit test framework (#10)

* add first Unit Test
with gtest and cmake dependencies

* optionally build tests or not
added some realistic tests

* added ci compatible run configuration

* added test dependencies -lpthread -lm to work in debian correctly

* added some docs
and option infos

tests/UnitTest.cpp

@@ -0,0 +1,30 @@
+//
+// Created by lukas on 06.05.20.
+//
+
+#include <FileLogger.h>
+#include <api/IPAPI.h>
+#include <climits>
+#include "gtest/gtest.h"
+
+/**
+ * Test if default ip is 0.0.0.0 when last ip file doesn't exist.
+ */
+TEST(ReadIp, testzeroIpIfNotExists) {
+    FileLogger logger;
+    std::string oldip = logger.readip();
+    ASSERT_EQ(oldip, "0.0.0.0");
+}
+/**
+ * Test if default ip is 0.0.0.0 when last ip file doesn't exist.
+ */
+TEST(IPAPI, testIpAPIcheckIPSyntax) {
+    IPAPI ipapi;
+    std::string ip = ipapi.getGlobalIp();
+    if (ip.find('.') == ULONG_MAX) {
+        // error when ip doesn't contain a .
+        ASSERT_TRUE(false);
+    } else {
+        ASSERT_TRUE(true);
+    }
+}