diff --git a/tests/CMakeLists.txt b/tests/CMakeLists.txt
index bbedbe88..bfbbdc4c 100644
--- a/tests/CMakeLists.txt
+++ b/tests/CMakeLists.txt
@@ -35,6 +35,7 @@ set(test_SOURCES
     ${CMAKE_CURRENT_LIST_DIR}/src/InputCompletion.cpp
     ${CMAKE_CURRENT_LIST_DIR}/src/XDGDesktopFile.cpp
     ${CMAKE_CURRENT_LIST_DIR}/src/XDGHelper.cpp
+    ${CMAKE_CURRENT_LIST_DIR}/src/XDGDirectory.cpp
     ${CMAKE_CURRENT_LIST_DIR}/src/Selection.cpp
     ${CMAKE_CURRENT_LIST_DIR}/src/NotebookTab.cpp
     ${CMAKE_CURRENT_LIST_DIR}/src/SplitInput.cpp
diff --git a/tests/src/Test.cpp b/tests/src/Test.cpp
index 5f245f5d..db63b2d9 100644
--- a/tests/src/Test.cpp
+++ b/tests/src/Test.cpp
@@ -40,3 +40,10 @@ void PrintTo(const QString &str, std::ostream *os)
 {
     ::testing::internal::UniversalPrint(str.toStdU16String(), os);
 }
+
+std::unique_lock<std::mutex> environmentLock()
+{
+    static std::mutex m;
+
+    return std::unique_lock(m);
+}
diff --git a/tests/src/Test.hpp b/tests/src/Test.hpp
index a44e244a..74528aa8 100644
--- a/tests/src/Test.hpp
+++ b/tests/src/Test.hpp
@@ -3,6 +3,7 @@
 #include <gmock/gmock.h>  // IWYU pragma: export
 #include <gtest/gtest.h>  // IWYU pragma: export
 
+#include <mutex>
 #include <ostream>
 
 class QString;
@@ -20,3 +21,7 @@ void PrintTo(const QByteArray &bytes, std::ostream *os);
 void PrintTo(QStringView str, std::ostream *os);
 void PrintTo(const QString &str, std::ostream *os);
 // NOLINTEND(readability-identifier-naming)
+
+/// Use this lock when your test relies on certain environment variables being set.
+/// It essentially helps ensure tests that rely on the same process environment variables cannot run in parallel
+std::unique_lock<std::mutex> environmentLock();
diff --git a/tests/src/XDGDirectory.cpp b/tests/src/XDGDirectory.cpp
new file mode 100644
index 00000000..2a780ec5
--- /dev/null
+++ b/tests/src/XDGDirectory.cpp
@@ -0,0 +1,144 @@
+#include "util/XDGDirectory.hpp"
+
+#include "Test.hpp"
+#include "util/CombinePath.hpp"
+
+#include <QDebug>
+#include <QTemporaryDir>
+#include <QtEnvironmentVariables>
+
+#if defined(Q_OS_UNIX) and !defined(Q_OS_DARWIN)
+
+using namespace chatterino;
+
+namespace {
+
+class TempEnv
+{
+public:
+    TempEnv(const char *key_, const QString &value_)
+        : key(key_)
+        , value(value_)
+        , prevValue(qEnvironmentVariable(this->key))
+    {
+        if (!this->value.isNull())
+        {
+            qDebug() << "Setting" << qPrintable(this->key) << "from"
+                     << this->prevValue << "to" << this->value;
+            qputenv(this->key, this->value.toLocal8Bit());
+        }
+        else
+        {
+            qDebug() << "Unsetting" << qPrintable(this->key)
+                     << "- old value was" << this->prevValue;
+            qunsetenv(this->key);
+        }
+    }
+
+    TempEnv(const TempEnv &) = delete;
+    TempEnv(TempEnv &&) = delete;
+    TempEnv &operator=(const TempEnv &) = delete;
+    TempEnv &operator=(TempEnv &&) = delete;
+
+    ~TempEnv()
+    {
+        if (!this->prevValue.isNull())
+        {
+            qDebug() << "Reverting" << qPrintable(this->key) << "to"
+                     << this->prevValue;
+            qputenv(this->key, this->prevValue.toLocal8Bit());
+        }
+        else
+        {
+            qDebug() << "Unsetting" << qPrintable(this->key) << "to"
+                     << this->prevValue;
+            qunsetenv(this->key);
+        }
+    }
+
+    const QString &getValue() const
+    {
+        return this->value;
+    }
+
+private:
+    const char *key;
+    QString value;
+    QString prevValue;
+};
+
+}  // namespace
+
+/// Test the returned directories from XDGDirectoryType::Config when no extra environment variables are set
+TEST(XDGDirectory, ConfigDefault)
+{
+    QTemporaryDir tmp;
+    auto lock = environmentLock();
+
+    TempEnv home("HOME", combinePath(tmp.path(), "home"));
+    TempEnv dataHome("XDG_CONFIG_HOME", {});
+    TempEnv dataDirs("XDG_CONFIG_DIRS", {});
+
+    auto actual = getXDGDirectories(XDGDirectoryType::Config);
+
+    ASSERT_EQ(actual.at(0), combinePath(home.getValue(), ".config/"));
+    ASSERT_EQ(actual.at(1), "/etc/xdg");
+
+    ASSERT_EQ(actual.length(), 2);
+}
+
+TEST(XDGDirectory, ConfigCustom)
+{
+    auto lock = environmentLock();
+
+    TempEnv dataHome("XDG_CONFIG_HOME", "/tmp/home-data");
+    TempEnv dataDirs("XDG_CONFIG_DIRS", "/tmp/sys-data-1:/tmp/sys-data-2");
+
+    auto actual = getXDGDirectories(XDGDirectoryType::Config);
+
+    ASSERT_EQ(actual.at(0), "/tmp/home-data");
+    ASSERT_EQ(actual.at(1), "/tmp/sys-data-1");
+    ASSERT_EQ(actual.at(2), "/tmp/sys-data-2");
+
+    ASSERT_EQ(actual.length(), 3);
+}
+
+/// Test the returned directories from XDGDirectoryType::Data when no extra environment variables are set
+TEST(XDGDirectory, DataDefault)
+{
+    QTemporaryDir tmp;
+    auto lock = environmentLock();
+
+    TempEnv home("HOME", combinePath(tmp.path(), "home"));
+    TempEnv dataHome("XDG_DATA_HOME", {});
+    TempEnv dataDirs("XDG_DATA_DIRS", {});
+
+    auto actual = getXDGDirectories(XDGDirectoryType::Data);
+
+    ASSERT_EQ(actual.at(0), combinePath(home.getValue(), ".local/share/"));
+    ASSERT_EQ(actual.at(1), "/usr/local/share/");
+    ASSERT_EQ(actual.at(2), "/usr/share/");
+
+    ASSERT_EQ(actual.length(), 3);
+}
+
+/// Test the returned directories from XDGDirectoryType::Data when user custom-configured environment variables are set
+TEST(XDGDirectory, DataCustom)
+{
+    auto lock = environmentLock();
+
+    TempEnv dataHome("XDG_DATA_HOME", "/tmp/home-share");
+    TempEnv dataDirs("XDG_DATA_DIRS",
+                     "/tmp/sys-share-1:/tmp/sys-share-2:/tmp/sys-share-3");
+
+    auto actual = getXDGDirectories(XDGDirectoryType::Data);
+
+    ASSERT_EQ(actual.at(0), "/tmp/home-share");
+    ASSERT_EQ(actual.at(1), "/tmp/sys-share-1");
+    ASSERT_EQ(actual.at(2), "/tmp/sys-share-2");
+    ASSERT_EQ(actual.at(3), "/tmp/sys-share-3");
+
+    ASSERT_EQ(actual.length(), 4);
+}
+
+#endif