refactor: move env outside from rust namespace

test/yycc/env.cpp

@@ -0,0 +1,62 @@
+#include <gtest/gtest.h>
+#include <yycc.hpp>
+#include <yycc/env.hpp>
+#include <yycc/macro/os_detector.hpp>
+#include <filesystem>
+
+#define ENV ::yycc::env
+
+namespace yycctest::env {
+
+    constexpr char8_t VAR_NAME[] = u8"HOMER";
+    constexpr char8_t VAR_VALUE[] = u8"doh";
+
+    TEST(Env, EnvVar) {
+        // Write a new variable should okey
+        {
+            auto rv = ENV::set_var(VAR_NAME, VAR_VALUE);
+            ASSERT_TRUE(rv.has_value());
+        }
+
+        // After writing, we can fetch it and check its value.
+        {
+            auto rv = ENV::get_var(VAR_NAME);
+            ASSERT_TRUE(rv.has_value());
+            EXPECT_EQ(rv.value(), VAR_VALUE);
+        }
+
+        // The we can delete it.
+        {
+            auto rv = ENV::del_var(VAR_NAME);
+            ASSERT_TRUE(rv.has_value());
+        }
+
+        // Delete inexisting variable also should be okey
+        {
+            auto rv = ENV::del_var(VAR_NAME);
+            ASSERT_TRUE(rv.has_value());
+        }
+
+        // After deleting, we can not fetch it anymore.
+        {
+            auto rv = ENV::get_var(VAR_NAME);
+            ASSERT_FALSE(rv.has_value());
+        }
+    }
+
+    TEST(Env, CurrentExe) {
+        auto rv = ENV::current_exe();
+        ASSERT_TRUE(rv.has_value());
+
+        std::filesystem::path p(rv.value());
+        auto filename = p.filename().u8string();
+#if defined(YYCC_OS_WINDOWS)
+        // Only Windows has special ext.
+        EXPECT_EQ(filename, u8"YYCCTest.exe");
+#else
+        // Executable in other system are all in plain name.
+        EXPECT_EQ(filename, u8"YYCCTest");
+#endif
+    }
+
+} // namespace yycctest::env