fix(tests): isolate test databases to prevent production data loss

CRITICAL BUG FIX: Tests were using production database and deleting all data

The root cause was in storage_test.go line 26:
  defer os.RemoveAll(os.ExpandEnv("$HOME/.local/share/codeme"))

This caused complete data loss when running 'go test ./...'. Tests would:
1. Use OpenDB() which opened the PRODUCTION database
2. Execute DELETE FROM heartbeats to "clean up"
3. Delete the entire production database directory on exit

Changes made to prevent this:
- Created OpenDBWithPath() to allow custom database location
- Added shared setupTestDB() helper in testhelper_test.go
- Updated all test files to use isolated temporary databases via t.TempDir()
- Removed dangerous os.RemoveAll() calls
- Removed unnecessary DELETE cleanup (temp dirs auto-cleanup)

Tests now use completely isolated databases that are automatically
cleaned up by Go's testing framework. Production database is never
touched during tests.

Verified:
- All tests pass with isolated databases
- Production database remains intact after running tests
- No data loss occurs when running go test ./...

Author: tduyng

core/integration_test.go

@@ -7,15 +7,9 @@ import (
 
 func TestEndToEnd(t *testing.T) {
 	// Create test database
-	db, err := OpenDB()
-	if err != nil {
-		t.Fatalf("Failed to open database: %v", err)
-	}
+	db := setupTestDB(t)
 	defer db.Close()
 
-	// Clear any existing data
-	db.Exec("DELETE FROM heartbeats")
-
 	// Simulate a coding session
 	session := []struct {
 		file         string
@@ -106,21 +100,12 @@ func TestEndToEnd(t *testing.T) {
 	if stats.TodayLines != expectedTotalLines {
 		t.Errorf("TodayLines = %d, want %d", stats.TodayLines, expectedTotalLines)
 	}
-
-	// Clean up
-	db.Exec("DELETE FROM heartbeats")
 }
 
 func TestMultipleDayStats(t *testing.T) {
-	db, err := OpenDB()
-	if err != nil {
-		t.Fatalf("Failed to open database: %v", err)
-	}
+	db := setupTestDB(t)
 	defer db.Close()
 
-	// Clear any existing data
-	db.Exec("DELETE FROM heartbeats")
-
 	// Simulate activity over 3 consecutive days
 	now := time.Now()
 	today := time.Date(now.Year(), now.Month(), now.Day(), 10, 0, 0, 0, now.Location())
@@ -176,7 +161,4 @@ func TestMultipleDayStats(t *testing.T) {
 	if len(stats.DailyActivity) != 3 {
 		t.Errorf("DailyActivity count = %d, want 3", len(stats.DailyActivity))
 	}
-
-	// Clean up
-	db.Exec("DELETE FROM heartbeats")
 }

core/stats_test.go

@@ -101,15 +101,9 @@ func TestCalculateLongestStreak(t *testing.T) {
 
 func TestCalculateStats(t *testing.T) {
 	// Create test database
-	db, err := OpenDB()
-	if err != nil {
-		t.Fatalf("Failed to open database: %v", err)
-	}
+	db := setupTestDB(t)
 	defer db.Close()
 
-	// Clear any existing data
-	db.Exec("DELETE FROM heartbeats")
-
 	// Insert test data
 	now := time.Now()
 	testData := []Heartbeat{
@@ -188,7 +182,4 @@ func TestCalculateStats(t *testing.T) {
 	if stats.TotalTime < expectedTime-tolerance || stats.TotalTime > expectedTime+tolerance {
 		t.Errorf("TotalTime = %d, want ~%d (±%d)", stats.TotalTime, expectedTime, tolerance)
 	}
-
-	// Clean up
-	db.Exec("DELETE FROM heartbeats")
 }

core/storage.go

@@ -70,8 +70,19 @@ func MigrateSchema(db *sql.DB) error {
 }
 
 func OpenDB() (*sql.DB, error) {
-	home, _ := os.UserHomeDir()
-	dbPath := filepath.Join(home, ".local", "share", "codeme", "codeme.db")
+	return OpenDBWithPath("")
+}
+
+// OpenDBWithPath opens a database at the specified path, or uses default if empty
+func OpenDBWithPath(customPath string) (*sql.DB, error) {
+	var dbPath string
+
+	if customPath != "" {
+		dbPath = customPath
+	} else {
+		home, _ := os.UserHomeDir()
+		dbPath = filepath.Join(home, ".local", "share", "codeme", "codeme.db")
+	}
 
 	os.MkdirAll(filepath.Dir(dbPath), 0755)
 

core/storage_test.go

@@ -1,29 +1,24 @@
 package core
 
 import (
-	"os"
 	"testing"
 )
 
 func TestOpenDB(t *testing.T) {
-	db, err := OpenDB()
-	if err != nil {
-		t.Fatalf("OpenDB() error = %v", err)
-	}
+	db := setupTestDB(t)
 	defer db.Close()
 
 	// Verify table exists
 	var count int
-	err = db.QueryRow("SELECT COUNT(*) FROM sqlite_master WHERE type='table' AND name='heartbeats'").Scan(&count)
+	err := db.QueryRow("SELECT COUNT(*) FROM sqlite_master WHERE type='table' AND name='heartbeats'").Scan(&count)
 	if err != nil || count != 1 {
 		t.Errorf("heartbeats table not created")
 	}
 }
 
 func TestSaveHeartbeat(t *testing.T) {
-	db, _ := OpenDB()
+	db := setupTestDB(t)
 	defer db.Close()
-	defer os.RemoveAll(os.ExpandEnv("$HOME/.local/share/codeme"))
 
 	hb := Heartbeat{
 		File:     "/test/file.go",

core/testhelper_test.go

@@ -0,0 +1,19 @@
+package core
+
+import (
+	"database/sql"
+	"path/filepath"
+	"testing"
+)
+
+// setupTestDB creates an isolated test database in a temporary directory
+// This helper is shared across all test files in the core package
+func setupTestDB(t *testing.T) *sql.DB {
+	tmpDir := t.TempDir()
+	testDB := filepath.Join(tmpDir, "test.db")
+	db, err := OpenDBWithPath(testDB)
+	if err != nil {
+		t.Fatalf("Failed to create test database: %v", err)
+	}
+	return db
+}

core/tracker_test.go

@@ -5,15 +5,9 @@ import (
 )
 
 func TestTrack(t *testing.T) {
-	db, err := OpenDB()
-	if err != nil {
-		t.Fatalf("Failed to open database: %v", err)
-	}
+	db := setupTestDB(t)
 	defer db.Close()
 
-	// Clear existing data
-	db.Exec("DELETE FROM heartbeats")
-
 	tests := []struct {
 		name         string
 		file         string
@@ -77,23 +71,14 @@ func TestTrack(t *testing.T) {
 			}
 		})
 	}
-
-	// Clean up
-	db.Exec("DELETE FROM heartbeats")
 }
 
 func TestTrackWithChangedLines(t *testing.T) {
-	db, err := OpenDB()
-	if err != nil {
-		t.Fatalf("Failed to open database: %v", err)
-	}
+	db := setupTestDB(t)
 	defer db.Close()
 
-	// Clear existing data
-	db.Exec("DELETE FROM heartbeats")
-
 	// Track initial file
-	err = Track(db, "/test/evolving.go", "Go", 100, 100)
+	err := Track(db, "/test/evolving.go", "Go", 100, 100)
 	if err != nil {
 		t.Fatalf("First Track() error = %v", err)
 	}
@@ -122,7 +107,4 @@ func TestTrackWithChangedLines(t *testing.T) {
 	if linesTotal != 110 {
 		t.Errorf("lines_total = %d, want 110", linesTotal)
 	}
-
-	// Clean up
-	db.Exec("DELETE FROM heartbeats")
 }