diff --git a/tests/CMakeLists.txt b/tests/CMakeLists.txt
index 06b16c8a159..08cb44acf9f 100644
--- a/tests/CMakeLists.txt
+++ b/tests/CMakeLists.txt
@@ -35,6 +35,7 @@ set(test_SOURCES
     ${CMAKE_CURRENT_LIST_DIR}/src/Literals.cpp
     ${CMAKE_CURRENT_LIST_DIR}/src/XDGDesktopFile.cpp
     ${CMAKE_CURRENT_LIST_DIR}/src/XDGHelper.cpp
+    ${CMAKE_CURRENT_LIST_DIR}/src/Selection.cpp
     # Add your new file above this line!
     )
 
diff --git a/tests/src/Selection.cpp b/tests/src/Selection.cpp
new file mode 100644
index 00000000000..1f1f4a62137
--- /dev/null
+++ b/tests/src/Selection.cpp
@@ -0,0 +1,152 @@
+#include "messages/Selection.hpp"
+
+#include <gtest/gtest.h>
+
+using namespace chatterino;
+
+TEST(Selection, SelectionItemEmpty)
+{
+    auto a = SelectionItem{};
+    ASSERT_EQ(a.charIndex, 0);
+    ASSERT_EQ(a.messageIndex, 0);
+}
+
+TEST(Selection, SelectionItemLt)
+{
+    auto a = SelectionItem{1, 5};
+    ASSERT_FALSE(a < a);
+
+    auto b = SelectionItem{1, 10};
+    ASSERT_LT(a, b);
+
+    auto c = SelectionItem{20, 0};
+    ASSERT_LT(a, c);
+}
+
+TEST(Selection, SelectionItemGt)
+{
+    auto a = SelectionItem{20, 0};
+    ASSERT_FALSE(a > a);
+
+    auto b = SelectionItem{1, 5};
+    ASSERT_GT(a, b);
+
+    auto c = SelectionItem{1, 10};
+    ASSERT_GT(a, c);
+}
+
+TEST(Selection, SelectionItemEq)
+{
+    auto a = SelectionItem{1, 2};
+    auto b = SelectionItem{1, 2};
+
+    ASSERT_EQ(a, b);
+    ASSERT_FALSE(a != b);
+
+    auto c = SelectionItem{2, 1};
+    auto d = SelectionItem{1, 0};
+
+    ASSERT_NE(a, d);
+    ASSERT_FALSE(a == c);
+}
+
+TEST(Selection, SelectionEmpty)
+{
+    auto a = Selection{};
+    ASSERT_TRUE(a.isEmpty());
+}
+
+TEST(Selection, SelectionEq)
+{
+    auto a = Selection{{5, 5}, {10, 10}};
+    auto b = Selection{{5, 5}, {10, 10}};
+
+    ASSERT_EQ(a, b);
+    ASSERT_FALSE(a != b);
+
+    auto c = Selection{{15, 15}, {5, 5}};
+    auto d = Selection{{10, 10}, {5, 5}};
+
+    ASSERT_NE(a, d);
+    ASSERT_FALSE(a == c);
+}
+
+TEST(Selection, SelectionMinMax)
+{
+    auto a = Selection{{1, 1}, {1, 2}};
+    ASSERT_EQ(a.selectionMin, a.start);
+    ASSERT_EQ(a.selectionMax, a.end);
+
+    auto b = Selection{{2, 0}, {1, 10}};
+    ASSERT_EQ(b.selectionMin, b.end);
+    ASSERT_EQ(b.selectionMax, b.start);
+}
+
+TEST(Selection, SelectionUnion)
+{
+    {
+        auto a = Selection{{1, 1}, {1, 10}};
+        auto b = Selection{{1, 20}, {1, 30}};
+        auto ab = a | b;
+
+        ASSERT_EQ(ab.start, a.start);
+        ASSERT_EQ(ab.end, b.end);
+    }
+
+    {
+        auto a = Selection{{10, 0}, {5, 50}};
+        auto b = Selection{{20, 0}, {25, 25}};
+        auto ab = a | b;
+
+        ASSERT_EQ(ab.start, a.end);
+        ASSERT_EQ(ab.end, b.end);
+    }
+
+    {
+        auto a = Selection{{3, 3}, {2, 1}};
+        auto b = Selection{{1, 0}, {1, 10}};
+        auto ab = a | b;
+
+        ASSERT_EQ(ab.start, b.start);
+        ASSERT_EQ(ab.end, a.start);
+
+        auto ba = b | a;
+        ASSERT_EQ(ab, ba);
+    }
+}
+
+TEST(Selection, SelectionSingleMessage)
+{
+    auto a = Selection{{1, 1}, {1, 2}};
+    ASSERT_TRUE(a.isSingleMessage());
+
+    auto b = Selection{{1, 1}, {2, 2}};
+    ASSERT_FALSE(b.isSingleMessage());
+}
+
+TEST(Selection, ShiftMessageIndex)
+{
+    auto a = Selection{{100, 1}, {200, 2}};
+
+    a.shiftMessageIndex(10);
+    ASSERT_EQ(a.selectionMin, a.start);
+    ASSERT_EQ(a.selectionMin.charIndex, 1);
+    ASSERT_EQ(a.selectionMin.messageIndex, 90);
+    ASSERT_EQ(a.selectionMax, a.end);
+    ASSERT_EQ(a.selectionMax.charIndex, 2);
+    ASSERT_EQ(a.selectionMax.messageIndex, 190);
+
+    a.shiftMessageIndex(20);
+    ASSERT_EQ(a.selectionMin, a.start);
+    ASSERT_EQ(a.selectionMin.messageIndex, 70);
+    ASSERT_EQ(a.selectionMax, a.end);
+    ASSERT_EQ(a.selectionMax.messageIndex, 170);
+
+    a.shiftMessageIndex(180);
+    ASSERT_EQ(a.selectionMin.messageIndex, 0);
+    ASSERT_EQ(a.selectionMax.messageIndex, 0);
+    ASSERT_EQ(a.start.messageIndex, 0);
+    ASSERT_EQ(a.end.messageIndex, 0);
+    ASSERT_EQ(a.start.charIndex, 0);
+    ASSERT_EQ(a.end.charIndex, 0);
+}