diff --git a/.coveragerc b/.coveragerc
new file mode 100644
index 0000000..c1e43ee
--- /dev/null
+++ b/.coveragerc
@@ -0,0 +1,7 @@
+[run]
+omit =
+    tests/*
+    */site-packages/*
+
+[report]
+show_missing = True
diff --git a/.gitea/workflows/lint.yml b/.gitea/workflows/lint.yml
index ecb4021..942f6e3 100644
--- a/.gitea/workflows/lint.yml
+++ b/.gitea/workflows/lint.yml
@@ -21,3 +21,21 @@ jobs:
 
       - name: Run flake8
         run: flake8 . --exclude=__pycache__,.git
+
+  notify-failure:
+    name: Notify on failure
+    runs-on: ubuntu-latest
+    needs: [python-lint]
+    if: failure() && github.event_name == 'push'
+    steps:
+      - name: Send Matrix alert
+        env:
+          MATRIX_WEBHOOK_URL: ${{ secrets.MATRIX_WEBHOOK_URL }}
+          REPO: ${{ github.repository }}
+          BRANCH: ${{ github.ref_name }}
+          RUN_URL: ${{ github.server_url }}/${{ github.repository }}/actions/runs/${{ github.run_id }}
+        run: |
+          if [ -z "$MATRIX_WEBHOOK_URL" ] || [ "$MATRIX_WEBHOOK_URL" = "CONFIGURE_ME" ]; then exit 0; fi
+          curl -sf -X POST "$MATRIX_WEBHOOK_URL" \
+            -H "Content-Type: application/json" \
+            -d "{\"text\":\"CI FAILED: ${REPO} @ ${BRANCH} — ${RUN_URL}\"}"
diff --git a/.gitea/workflows/test.yml b/.gitea/workflows/test.yml
new file mode 100644
index 0000000..b335c68
--- /dev/null
+++ b/.gitea/workflows/test.yml
@@ -0,0 +1,23 @@
+name: Test
+
+on:
+  push:
+    branches: ["**"]
+  pull_request:
+    branches: ["**"]
+
+jobs:
+  pytest:
+    name: Python Tests (pytest)
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v3
+
+      - name: Install Python and dependencies
+        run: |
+          apt-get update -qq
+          apt-get install -y -qq python3 python3-pip python3-pytest python3-psutil python3-requests
+          pip3 install pytest-cov
+
+      - name: Run pytest with coverage
+        run: python3 -m pytest tests/ -v --cov=. --cov-report=term-missing --cov-config=.coveragerc
diff --git a/.gitignore b/.gitignore
index 9c68ef2..c86df22 100644
--- a/.gitignore
+++ b/.gitignore
@@ -1,2 +1,4 @@
 .claude
-settings.local.json
\ No newline at end of file
+settings.local.json
+__pycache__/
+*.pyc
\ No newline at end of file
diff --git a/tests/test_hwmon.py b/tests/test_hwmon.py
new file mode 100644
index 0000000..327495f
--- /dev/null
+++ b/tests/test_hwmon.py
@@ -0,0 +1,222 @@
+"""Tests for SystemHealthMonitor pure methods — no external processes or filesystem."""
+import sys
+import os
+from unittest.mock import patch, MagicMock
+sys.path.insert(0, os.path.dirname(os.path.dirname(__file__)))
+
+import pytest
+from hwmonDaemon import SystemHealthMonitor
+
+
+@pytest.fixture(scope='module')
+def monitor():
+    """Create a minimal monitor instance with all external side-effects patched out."""
+    with patch.object(SystemHealthMonitor, 'load_env_config'), \
+         patch.object(SystemHealthMonitor, '_check_tool_availability', return_value={}), \
+         patch('os.makedirs'):
+        return SystemHealthMonitor(dry_run=True)
+
+
+# ── _format_bytes_human ──────────────────────────────────────────────────────
+
+class TestFormatBytesHuman:
+    def test_bytes(self, monitor):
+        assert monitor._format_bytes_human(512) == '512.0 B'
+
+    def test_kilobytes(self, monitor):
+        assert monitor._format_bytes_human(1024) == '1.0 KB'
+
+    def test_megabytes(self, monitor):
+        assert monitor._format_bytes_human(1024 ** 2) == '1.0 MB'
+
+    def test_gigabytes(self, monitor):
+        assert monitor._format_bytes_human(1024 ** 3) == '1.0 GB'
+
+    def test_terabytes(self, monitor):
+        assert monitor._format_bytes_human(1024 ** 4) == '1.0 TB'
+
+    def test_fractional(self, monitor):
+        assert monitor._format_bytes_human(1536) == '1.5 KB'
+
+    def test_zero(self, monitor):
+        assert monitor._format_bytes_human(0) == '0.0 B'
+
+
+# ── _parse_size ───────────────────────────────────────────────────────────────
+
+class TestParseSize:
+    def test_gigabytes(self, monitor):
+        result = monitor._parse_size('15.7G')
+        assert abs(result - 15.7 * 1024**3) < 1
+
+    def test_terabytes(self, monitor):
+        result = monitor._parse_size('21.8T')
+        assert abs(result - 21.8 * 1024**4) < 1
+
+    def test_megabytes(self, monitor):
+        result = monitor._parse_size('512M')
+        assert result == 512 * 1024**2
+
+    def test_kilobytes(self, monitor):
+        result = monitor._parse_size('100K')
+        assert result == 100 * 1024
+
+    def test_bytes(self, monitor):
+        result = monitor._parse_size('100B')
+        assert result == 100
+
+    def test_invalid_returns_zero(self, monitor):
+        assert monitor._parse_size('notasize') == 0.0
+
+    def test_non_string_returns_zero(self, monitor):
+        assert monitor._parse_size(None) == 0.0
+        assert monitor._parse_size(42) == 0.0
+
+
+# ── _parse_smart_value ────────────────────────────────────────────────────────
+
+class TestParseSmartValue:
+    def test_plain_integer(self, monitor):
+        assert monitor._parse_smart_value('42') == 42
+
+    def test_temperature_with_celsius(self, monitor):
+        assert monitor._parse_smart_value('38 °C') == 38
+
+    def test_time_format(self, monitor):
+        assert monitor._parse_smart_value('15589h+17m+33.939s') == 15589
+
+    def test_hex_value(self, monitor):
+        assert monitor._parse_smart_value('0x0a') == 10
+
+    def test_invalid_returns_zero(self, monitor):
+        assert monitor._parse_smart_value('not_a_number') == 0
+
+
+# ── _detect_manufacturer ──────────────────────────────────────────────────────
+
+class TestDetectManufacturer:
+    def test_western_digital(self, monitor):
+        assert monitor._detect_manufacturer('WDC WD40EFRX') == 'Western Digital'
+
+    def test_hgst(self, monitor):
+        assert monitor._detect_manufacturer('HGST HUH728080ALE604') == 'Western Digital'
+
+    def test_seagate(self, monitor):
+        assert monitor._detect_manufacturer('ST4000DM004') == 'Seagate'
+
+    def test_samsung(self, monitor):
+        assert monitor._detect_manufacturer('Samsung SSD 870 EVO') == 'Samsung'
+
+    def test_intel(self, monitor):
+        assert monitor._detect_manufacturer('INTEL SSDSC2KB480G8') == 'Intel'
+
+    def test_micron(self, monitor):
+        assert monitor._detect_manufacturer('Crucial CT500MX500SSD1') == 'Micron'
+
+    def test_toshiba(self, monitor):
+        assert monitor._detect_manufacturer('TOSHIBA MG06ACA10TE') == 'Toshiba'
+
+    def test_unknown(self, monitor):
+        assert monitor._detect_manufacturer('GENERICDRIVE XYZ') == 'Unknown'
+
+    def test_empty_model(self, monitor):
+        assert monitor._detect_manufacturer('') == 'Unknown'
+
+    def test_none_model(self, monitor):
+        assert monitor._detect_manufacturer(None) == 'Unknown'
+
+
+# ── _check_thermal_health ─────────────────────────────────────────────────────
+
+class TestCheckThermalHealth:
+    def test_hdd_ok_temperature(self, monitor):
+        issues = monitor._check_thermal_health('sda', 45, 'HDD')
+        assert issues == []
+
+    def test_hdd_info_temperature(self, monitor):
+        issues = monitor._check_thermal_health('sda', 62, 'HDD')
+        assert len(issues) == 1
+        assert 'INFO' in issues[0]
+
+    def test_hdd_warning_temperature(self, monitor):
+        issues = monitor._check_thermal_health('sda', 66, 'HDD')
+        assert len(issues) == 1
+        assert 'WARNING' in issues[0]
+
+    def test_hdd_critical_temperature(self, monitor):
+        issues = monitor._check_thermal_health('sda', 76, 'HDD')
+        assert len(issues) == 1
+        assert 'CRITICAL' in issues[0]
+
+    def test_ssd_has_higher_warning_threshold(self, monitor):
+        # HDD warning=65°C, SSD warning=70°C; at 67°C:
+        # HDD → WARNING, SSD → INFO (above optimal_max=65 but below warning=70)
+        issues_hdd = monitor._check_thermal_health('sda', 67, 'HDD')
+        issues_ssd = monitor._check_thermal_health('sda', 67, 'SSD')
+        assert any('WARNING' in i for i in issues_hdd)
+        assert not any('WARNING' in i for i in issues_ssd)
+        assert any('INFO' in i for i in issues_ssd)
+
+    def test_none_temperature_returns_empty(self, monitor):
+        issues = monitor._check_thermal_health('sda', None, 'HDD')
+        assert issues == []
+
+
+# ── _is_excluded_mount ────────────────────────────────────────────────────────
+
+class TestIsExcludedMount:
+    def test_exact_excluded_mount(self, monitor):
+        assert monitor._is_excluded_mount('/media') is True
+
+    def test_pattern_excluded(self, monitor):
+        assert monitor._is_excluded_mount('/media/external') is True
+
+    def test_downloads_excluded(self, monitor):
+        assert monitor._is_excluded_mount('/mnt/data/downloads') is True
+
+    def test_normal_mount_not_excluded(self, monitor):
+        assert monitor._is_excluded_mount('/') is False
+        assert monitor._is_excluded_mount('/var') is False
+        assert monitor._is_excluded_mount('/mnt/ceph') is False
+
+
+# ── _is_new_drive ─────────────────────────────────────────────────────────────
+
+class TestIsNewDrive:
+    def test_brand_new_drive(self, monitor):
+        assert monitor._is_new_drive(0) is True
+
+    def test_one_hour_drive(self, monitor):
+        assert monitor._is_new_drive(1) is True
+
+    def test_under_threshold(self, monitor):
+        assert monitor._is_new_drive(719) is True
+
+    def test_at_threshold_is_not_new(self, monitor):
+        assert monitor._is_new_drive(720) is False
+
+    def test_old_drive(self, monitor):
+        assert monitor._is_new_drive(50000) is False
+
+
+# ── _is_physical_disk ────────────────────────────────────────────────────────
+
+class TestIsPhysicalDisk:
+    def test_real_sata_disk(self, monitor):
+        # /dev/sda should pass (no exclusion pattern matches)
+        # Note: _is_physical_disk also checks os.path.exists and reads sysfs,
+        # but the exclusion logic runs first and can return False early.
+        # We test the exclusion cases which are pure.
+        assert monitor._is_physical_disk('/dev/mapper/data') is False
+
+    def test_device_mapper_excluded(self, monitor):
+        assert monitor._is_physical_disk('/dev/dm-0') is False
+
+    def test_loop_device_excluded(self, monitor):
+        assert monitor._is_physical_disk('/dev/loop0') is False
+
+    def test_partition_excluded(self, monitor):
+        assert monitor._is_physical_disk('/dev/sda1') is False
+
+    def test_rbd_excluded(self, monitor):
+        assert monitor._is_physical_disk('/dev/rbd0') is False