tests: add httpcommon tests and add new file_handler methods (#2712)

Co-authored-by: Mariotaku <mariotaku.lee@gmail.com>

tests/unit/test_httpcommon.cpp

@@ -0,0 +1,53 @@
+/**
+ * @file tests/test_httpcommon.cpp
+ * @brief Test src/httpcommon.*.
+ */
+#include <src/httpcommon.h>
+
+#include <tests/conftest.cpp>
+
+class UrlEscapeTest: public ::testing::TestWithParam<std::tuple<std::string, std::string>> {};
+
+TEST_P(UrlEscapeTest, Run) {
+  auto [input, expected] = GetParam();
+  ASSERT_EQ(http::url_escape(input), expected);
+}
+
+INSTANTIATE_TEST_SUITE_P(
+  UrlEscapeTests,
+  UrlEscapeTest,
+  ::testing::Values(
+    std::make_tuple("igdb_0123456789", "igdb_0123456789"),
+    std::make_tuple("../../../", "..%2F..%2F..%2F"),
+    std::make_tuple("..*\\", "..%2A%5C")));
+
+class UrlGetHostTest: public ::testing::TestWithParam<std::tuple<std::string, std::string>> {};
+
+TEST_P(UrlGetHostTest, Run) {
+  auto [input, expected] = GetParam();
+  ASSERT_EQ(http::url_get_host(input), expected);
+}
+
+INSTANTIATE_TEST_SUITE_P(
+  UrlGetHostTests,
+  UrlGetHostTest,
+  ::testing::Values(
+    std::make_tuple("https://images.igdb.com/example.txt", "images.igdb.com"),
+    std::make_tuple("http://localhost:8080", "localhost"),
+    std::make_tuple("nonsense!!}{::", "")));
+
+class DownloadFileTest: public ::testing::TestWithParam<std::tuple<std::string, std::string>> {};
+
+TEST_P(DownloadFileTest, Run) {
+  auto [url, filename] = GetParam();
+  const std::string test_dir = platf::appdata().string() + "/tests/";
+  std::basic_string path = test_dir + filename;
+  ASSERT_TRUE(http::download_file(url, path));
+}
+
+INSTANTIATE_TEST_SUITE_P(
+  DownloadFileTests,
+  DownloadFileTest,
+  ::testing::Values(
+    std::make_tuple("https://httpbin.org/base64/aGVsbG8h", "hello.txt"),
+    std::make_tuple("https://httpbin.org/redirect-to?url=/base64/aGVsbG8h", "hello-redirect.txt")));