diff --git a/README.md b/README.md
index 6883120..0258693 100644
--- a/README.md
+++ b/README.md
@@ -102,6 +102,18 @@ copy   = true   # copy result to clipboard
 notify = true   # show desktop notification with the copied value
 ```
 
+## 🧪 Testing
+
+The project includes a comprehensive test suite that verifies color conversion, configuration loading, and system integrations (clipboard/notifications) using mocks.
+
+To run the tests:
+
+```bash
+./tests/run_tests.sh
+```
+
+The test script creates a temporary isolated environment, so it won't affect your system configuration or active clipboard.
+
 ## 🤝 Credits
 
 The `wl-colorpicker-plasma` integration is based on the original work by [SASUPERNOVA](https://github.com/SASUPERNOVA/wl-colorpicker-plasma).
diff --git a/tests/run_tests.sh b/tests/run_tests.sh
new file mode 100755
index 0000000..32946f1
--- /dev/null
+++ b/tests/run_tests.sh
@@ -0,0 +1,149 @@
+#!/bin/bash
+set -euo pipefail
+
+# ── Setup ─────────────────────────────────────────────────────────────────────
+# Using a static-ish path since we can't use command substitution in cat
+TEST_DIR="/tmp/color-tool-tests-repro"
+BIN_DIR="$TEST_DIR/bin"
+rm -rf "$TEST_DIR"
+mkdir -p "$BIN_DIR"
+
+# Mock notify-send
+cat <<'MOCK' > "$BIN_DIR/notify-send"
+#!/bin/bash
+echo "NOTIFY: $*" >> "/tmp/color-tool-tests-repro/notify.log"
+MOCK
+
+# Mock wl-copy
+cat <<'MOCK' > "$BIN_DIR/wl-copy"
+#!/bin/bash
+cat > "/tmp/color-tool-tests-repro/clipboard.txt"
+MOCK
+
+# Mock python3
+cat <<'MOCK' > "$BIN_DIR/python3"
+#!/bin/bash
+if [[ "$*" == *wl-colorpicker*.py ]]; then
+  echo "#aabbcc"
+  exit 0
+fi
+exec /usr/bin/python3 "$@"
+MOCK
+
+chmod +x "$BIN_DIR"/*
+
+# Symlink essential tools
+ln -s /usr/bin/bash "$BIN_DIR/bash"
+ln -s /usr/bin/cat "$BIN_DIR/cat"
+ln -s /usr/bin/printf "$BIN_DIR/printf"
+ln -s /usr/bin/echo "$BIN_DIR/echo"
+ln -s /usr/bin/sed "$BIN_DIR/sed"
+ln -s /usr/bin/grep "$BIN_DIR/grep"
+ln -s /usr/bin/awk "$BIN_DIR/awk"
+ln -s /usr/bin/jq "$BIN_DIR/jq"
+ln -s /usr/bin/readlink "$BIN_DIR/readlink"
+ln -s /usr/bin/dirname "$BIN_DIR/dirname"
+ln -s /usr/bin/mkdir "$BIN_DIR/mkdir"
+ln -s /usr/bin/mktemp "$BIN_DIR/mktemp"
+ln -s /usr/bin/chmod "$BIN_DIR/chmod"
+ln -s /usr/bin/rm "$BIN_DIR/rm"
+ln -s /usr/bin/curl "$BIN_DIR/curl"
+
+export PATH="$BIN_DIR"
+export HOME="$TEST_DIR"
+export WAYLAND_DISPLAY=wayland-0
+export XDG_CURRENT_DESKTOP=KDE
+
+# Resolve the absolute path of color-tool
+COLOR_TOOL="$(/usr/bin/readlink -f ./color-tool)"
+
+# ── Test Helpers ──────────────────────────────────────────────────────────────
+total=0
+passed=0
+
+it() {
+  local label="$1"
+  total=$((total + 1))
+  printf "Test: %s... " "$label"
+}
+
+assert_contains() {
+  local haystack="$1"
+  local needle="$2"
+  if [[ "$haystack" == *"$needle"* ]]; then
+    echo "PASS"
+    passed=$((passed + 1))
+  else
+    echo "FAIL"
+    echo "  Expected to find: $needle"
+    echo "  Actual output: $haystack"
+    return 1
+  fi
+}
+
+# ── Tests ─────────────────────────────────────────────────────────────────────
+
+# 1. Basic Conversion
+it "converts hex to rgb"
+output=$("$COLOR_TOOL" "#ffffff" --output rgb --no-copy --no-notify)
+assert_contains "$output" "rgb(255, 255, 255)"
+
+# 2. Multiple Formats
+it "handles multiple formats"
+output=$("$COLOR_TOOL" "#000000" --output hex,rgba --no-copy --no-notify)
+assert_contains "$output" "#000000 rgba(0, 0, 0, 1.0)"
+
+# 3. Clipboard Integration
+it "copies to clipboard (mocked)"
+rm -f "$TEST_DIR/clipboard.txt"
+"$COLOR_TOOL" "#ff0000" --copy --no-notify >/dev/null
+if [[ -f "$TEST_DIR/clipboard.txt" ]]; then
+  assert_contains "$(cat "$TEST_DIR/clipboard.txt")" "#ff0000"
+else
+  echo "FAIL (clipboard.txt not created)"
+fi
+
+# 4. Notification Integration
+it "sends notifications (mocked)"
+rm -f "$TEST_DIR/notify.log"
+"$COLOR_TOOL" "#00ff00" --notify --no-copy >/dev/null
+if [[ -f "$TEST_DIR/notify.log" ]]; then
+  assert_contains "$(cat "$TEST_DIR/notify.log")" "NOTIFY: -i color-picker color-tool #00ff00"
+else
+  echo "FAIL (notify.log not created)"
+fi
+
+# 5. Color Picker (Mocked)
+it "launches color picker and processes result"
+output=$("$COLOR_TOOL" --pick --no-copy --no-notify)
+assert_contains "$output" "#aabbcc"
+
+# 6. Config Loading
+it "loads defaults from config.toml"
+mkdir -p "$HOME/.config/color-tool"
+cat <<'CONF' > "$HOME/.config/color-tool/config.toml"
+[defaults]
+output = "rgba"
+CONF
+output=$("$COLOR_TOOL" "#ffffff" --no-copy --no-notify)
+assert_contains "$output" "rgba(255, 255, 255, 1.0)"
+
+# 7. Error Notification
+it "notifies on missing clipboard utility"
+rm -f "$BIN_DIR/wl-copy"
+rm -f "$TEST_DIR/notify.log"
+"$COLOR_TOOL" "#123456" --copy --notify 2>/dev/null >/dev/null
+if [[ -f "$TEST_DIR/notify.log" ]]; then
+  assert_contains "$(cat "$TEST_DIR/notify.log")" "NOTIFY: -u normal -i dialog-warning color-tool Missing clipboard utility"
+else
+  echo "FAIL (notify.log not created)"
+fi
+
+# ── Cleanup ───────────────────────────────────────────────────────────────────
+echo "---------------------------------------"
+echo "Result: $passed/$total tests passed."
+rm -rf "$TEST_DIR"
+
+if [[ $passed -ne $total ]]; then
+  exit 1
+fi