Use on-disk SQLite databases to allow regular access methods, see mat…

…tn/go-sqlite3#632

cmd/bank/main.go

@@ -57,8 +57,8 @@ func run(ctx context.Context) error {
 	}
 	appName := os.Args[1]
 
-	db := sqltest.Open("postgres")
-	defer db.Close()
+	db, _, close := sqltest.Open("postgres")
+	defer close()
 
 	// TODO: return to using SQL
 	// if err := postgres.CreateSchema(ctx, db); err != nil {

internal/testing/boltdbtest/db.go

@@ -13,7 +13,7 @@ import (
 // The returned function must be used to close the database, instead of
 // DB.Close().
 func Open() (*bbolt.DB, func()) {
-	filename, remove := TempFile()
+	filename, remove := tempFile()
 
 	db, err := bbolt.Open(filename, 0600, nil)
 	if err != nil {
@@ -26,11 +26,11 @@ func Open() (*bbolt.DB, func()) {
 	}
 }
 
-// TempFile returns the name of a temporary file to be used for a BoltDB
+// tempFile returns the name of a temporary file to be used for a BoltDB
 // database.
 //
 // It returns a function that deletes the temporary file.
-func TempFile() (string, func()) {
+func tempFile() (string, func()) {
 	f, err := ioutil.TempFile("", "*.boltdb")
 	if err != nil {
 		panic(err)

internal/testing/sqltest/db.go

@@ -3,50 +3,98 @@ package sqltest
 import (
 	"database/sql"
 	"fmt"
+	"io/ioutil"
 	"os"
+	"sync"
 
 	_ "github.com/go-sql-driver/mysql" // keep driver import near code that uses it
-	"github.com/google/uuid"
-	_ "github.com/lib/pq"           // keep driver import near code that uses it
-	_ "github.com/mattn/go-sqlite3" // keep driver import near code that uses it
+	_ "github.com/lib/pq"              // keep driver import near code that uses it
+	_ "github.com/mattn/go-sqlite3"    // keep driver import near code that uses it
 )
 
 // DSN returns the DSN for the test database to use with the given SQL driver.
-func DSN(driver string) string {
-	var env, dsn string
+//
+// The returned function must be used to cleanup any data created for the DSN,
+// such as temporary on-disk databases.
+func DSN(driver string) (string, func()) {
+	dsn := dsnFromEnv(driver)
+	if dsn != "" {
+		return dsn, func() {}
+	}
 
 	switch driver {
 	case "mysql":
-		env = "DOGMATIQ_TEST_MYSQL_DSN"
-		dsn = "root:rootpass@tcp(127.0.0.1:3306)/dogmatiq"
-	case "sqlite3":
-		env = "DOGMATIQ_TEST_SQLITE_DSN"
-		dsn = fmt.Sprintf(
-			"file:sqlite-%s.db?cache=shared&mode=memory",
-			uuid.New().String(),
-		)
+		return "root:rootpass@tcp(127.0.0.1:3306)/dogmatiq", func() {}
 	case "postgres":
-		env = "DOGMATIQ_TEST_POSTGRES_DSN"
-		dsn = "user=postgres password=rootpass sslmode=disable"
+		return "user=postgres password=rootpass sslmode=disable", func() {}
 	default:
-		panic("unsupported driver: " + driver)
+		file, close := tempFile()
+		return fmt.Sprintf("file:%s?mode=rwc", file), close
 	}
+}
 
-	if v := os.Getenv(env); v != "" {
-		return v
+// Open returns the test database to use with the given driver.
+//
+// The returned function must be used to close the database, instead of
+// DB.Close().
+func Open(
+	driver string,
+) (
+	db *sql.DB,
+	dsn string,
+	close func(),
+) {
+	dsn, closeDSN := DSN(driver)
+
+	db, err := sql.Open(driver, dsn)
+	if err != nil {
+		panic(err)
 	}
 
-	return dsn
+	return db, dsn, func() {
+		db.Close()
+		closeDSN()
+	}
 }
 
-// Open returns the test database to use with the given driver.
-func Open(driver string) *sql.DB {
-	dsn := DSN(driver)
+// dsnFromEnv returns a DSN for the given driver from an environment variable.
+func dsnFromEnv(driver string) string {
+	switch driver {
+	case "mysql":
+		return os.Getenv("DOGMATIQ_TEST_MYSQL_DSN")
+	case "postgres":
+		return os.Getenv("DOGMATIQ_TEST_POSTGRES_DSN")
+	case "sqlite3":
+		return os.Getenv("DOGMATIQ_TEST_SQLITE_DSN")
+	default:
+		panic("unsupported driver: " + driver)
+	}
+}
 
-	db, err := sql.Open(driver, dsn)
+// tempFile returns the name of a temporary file to be used for an SQLite
+// database.
+//
+// It returns a function that deletes the temporary file.
+func tempFile() (string, func()) {
+	f, err := ioutil.TempFile("", "*.sqlite3")
 	if err != nil {
 		panic(err)
 	}
 
-	return db
+	if err := f.Close(); err != nil {
+		panic(err)
+	}
+
+	file := f.Name()
+
+	if err := os.Remove(file); err != nil {
+		panic(err)
+	}
+
+	var once sync.Once
+	return file, func() {
+		once.Do(func() {
+			os.Remove(file)
+		})
+	}
 }