CLI test coverage

cmd/litestream/Makefile

@@ -0,0 +1,6 @@
+.PHONY: default
+default:
+
+.PHONY: testdata
+testdata:
+	make -C testdata

cmd/litestream/databases.go

@@ -4,17 +4,30 @@ import (
 	"context"
 	"flag"
 	"fmt"
-	"os"
+	"io"
 	"strings"
 	"text/tabwriter"
 )
 
 // DatabasesCommand is a command for listing managed databases.
 type DatabasesCommand struct {
+	stdin  io.Reader
+	stdout io.Writer
+	stderr io.Writer
+
 	configPath  string
 	noExpandEnv bool
 }
 
+// NewDatabasesCommand returns a new instance of DatabasesCommand.
+func NewDatabasesCommand(stdin io.Reader, stdout, stderr io.Writer) *DatabasesCommand {
+	return &DatabasesCommand{
+		stdin:  stdin,
+		stdout: stdout,
+		stderr: stderr,
+	}
+}
+
 // Run executes the command.
 func (c *DatabasesCommand) Run(ctx context.Context, args []string) (err error) {
 	fs := flag.NewFlagSet("litestream-databases", flag.ContinueOnError)
@@ -27,16 +40,16 @@ func (c *DatabasesCommand) Run(ctx context.Context, args []string) (err error) {
 	}
 
 	// Load configuration.
-	if c.configPath == "" {
-		c.configPath = DefaultConfigPath()
-	}
 	config, err := ReadConfigFile(c.configPath, !c.noExpandEnv)
 	if err != nil {
 		return err
+	} else if len(config.DBs) == 0 {
+		fmt.Fprintln(c.stdout, "No databases found in config file.")
+		return nil
 	}
 
 	// List all databases.
-	w := tabwriter.NewWriter(os.Stdout, 0, 8, 2, ' ', 0)
+	w := tabwriter.NewWriter(c.stdout, 0, 8, 2, ' ', 0)
 	defer w.Flush()
 
 	fmt.Fprintln(w, "path\treplicas")
@@ -62,7 +75,7 @@ func (c *DatabasesCommand) Run(ctx context.Context, args []string) (err error) {
 
 // Usage prints the help screen to STDOUT.
 func (c *DatabasesCommand) Usage() {
-	fmt.Printf(`
+	fmt.Fprintf(c.stdout, `
 The databases command lists all databases in the configuration file.
 
 Usage:

cmd/litestream/databases_test.go

@@ -0,0 +1,66 @@
+package main_test
+
+import (
+	"context"
+	"flag"
+	"path/filepath"
+	"strings"
+	"testing"
+
+	"github.com/benbjohnson/litestream/internal/testingutil"
+)
+
+func TestDatabasesCommand(t *testing.T) {
+	t.Run("OK", func(t *testing.T) {
+		testDir := filepath.Join("testdata", "databases", "ok")
+		m, _, stdout, _ := newMain()
+		if err := m.Run(context.Background(), []string{"databases", "-config", filepath.Join(testDir, "litestream.yml")}); err != nil {
+			t.Fatal(err)
+		} else if got, want := stdout.String(), string(testingutil.MustReadFile(t, filepath.Join(testDir, "stdout"))); got != want {
+			t.Fatalf("stdout=%q, want %q", got, want)
+		}
+	})
+
+	t.Run("NoDatabases", func(t *testing.T) {
+		testDir := filepath.Join("testdata", "databases", "no-databases")
+		m, _, stdout, _ := newMain()
+		if err := m.Run(context.Background(), []string{"databases", "-config", filepath.Join(testDir, "litestream.yml")}); err != nil {
+			t.Fatal(err)
+		} else if got, want := stdout.String(), string(testingutil.MustReadFile(t, filepath.Join(testDir, "stdout"))); got != want {
+			t.Fatalf("stdout=%q, want %q", got, want)
+		}
+	})
+
+	t.Run("ErrConfigNotFound", func(t *testing.T) {
+		testDir := filepath.Join("testdata", "databases", "no-config")
+		m, _, _, _ := newMain()
+		err := m.Run(context.Background(), []string{"databases", "-config", filepath.Join(testDir, "litestream.yml")})
+		if err == nil || !strings.Contains(err.Error(), `config file not found:`) {
+			t.Fatalf("unexpected error: %s", err)
+		}
+	})
+
+	t.Run("ErrInvalidConfig", func(t *testing.T) {
+		testDir := filepath.Join("testdata", "databases", "invalid-config")
+		m, _, _, _ := newMain()
+		err := m.Run(context.Background(), []string{"databases", "-config", filepath.Join(testDir, "litestream.yml")})
+		if err == nil || !strings.Contains(err.Error(), `replica path cannot be a url`) {
+			t.Fatalf("unexpected error: %s", err)
+		}
+	})
+
+	t.Run("ErrTooManyArguments", func(t *testing.T) {
+		m, _, _, _ := newMain()
+		err := m.Run(context.Background(), []string{"databases", "xyz"})
+		if err == nil || err.Error() != `too many arguments` {
+			t.Fatalf("unexpected error: %s", err)
+		}
+	})
+
+	t.Run("Usage", func(t *testing.T) {
+		m, _, _, _ := newMain()
+		if err := m.Run(context.Background(), []string{"databases", "-h"}); err != flag.ErrHelp {
+			t.Fatalf("unexpected error: %s", err)
+		}
+	})
+}

cmd/litestream/generations.go

@@ -4,93 +4,80 @@ import (
 	"context"
 	"flag"
 	"fmt"
-	"log"
+	"io"
 	"os"
 	"text/tabwriter"
 	"time"
 
 	"github.com/benbjohnson/litestream"
+	"github.com/benbjohnson/litestream/internal"
 )
 
 // GenerationsCommand represents a command to list all generations for a database.
 type GenerationsCommand struct {
+	stdin  io.Reader
+	stdout io.Writer
+	stderr io.Writer
+
 	configPath  string
 	noExpandEnv bool
+
+	replicaName string
+}
+
+// NewGenerationsCommand returns a new instance of GenerationsCommand.
+func NewGenerationsCommand(stdin io.Reader, stdout, stderr io.Writer) *GenerationsCommand {
+	return &GenerationsCommand{
+		stdin:  stdin,
+		stdout: stdout,
+		stderr: stderr,
+	}
 }
 
 // Run executes the command.
-func (c *GenerationsCommand) Run(ctx context.Context, args []string) (err error) {
+func (c *GenerationsCommand) Run(ctx context.Context, args []string) (ret error) {
 	fs := flag.NewFlagSet("litestream-generations", flag.ContinueOnError)
 	registerConfigFlag(fs, &c.configPath, &c.noExpandEnv)
-	replicaName := fs.String("replica", "", "replica name")
+	fs.StringVar(&c.replicaName, "replica", "", "replica name")
 	fs.Usage = c.Usage
 	if err := fs.Parse(args); err != nil {
 		return err
-	} else if fs.NArg() == 0 || fs.Arg(0) == "" {
+	} else if fs.Arg(0) == "" {
 		return fmt.Errorf("database path or replica URL required")
 	} else if fs.NArg() > 1 {
 		return fmt.Errorf("too many arguments")
 	}
 
-	var db *litestream.DB
-	var r *litestream.Replica
-	dbUpdatedAt := time.Now()
-	if isURL(fs.Arg(0)) {
-		if c.configPath != "" {
-			return fmt.Errorf("cannot specify a replica URL and the -config flag")
-		}
-		if r, err = NewReplicaFromConfig(&ReplicaConfig{URL: fs.Arg(0)}, nil); err != nil {
-			return err
-		}
-	} else {
-		if c.configPath == "" {
-			c.configPath = DefaultConfigPath()
-		}
-
-		// Load configuration.
-		config, err := ReadConfigFile(c.configPath, !c.noExpandEnv)
-		if err != nil {
-			return err
-		}
-
-		// Lookup database from configuration file by path.
-		if path, err := expand(fs.Arg(0)); err != nil {
-			return err
-		} else if dbc := config.DBConfig(path); dbc == nil {
-			return fmt.Errorf("database not found in config: %s", path)
-		} else if db, err = NewDBFromConfig(dbc); err != nil {
-			return err
-		}
-
-		// Filter by replica, if specified.
-		if *replicaName != "" {
-			if r = db.Replica(*replicaName); r == nil {
-				return fmt.Errorf("replica %q not found for database %q", *replicaName, db.Path())
-			}
-		}
-
-		// Determine last time database or WAL was updated.
-		if dbUpdatedAt, err = db.UpdatedAt(); err != nil {
-			return err
-		}
+	// Load configuration.
+	config, err := ReadConfigFile(c.configPath, !c.noExpandEnv)
+	if err != nil {
+		return err
 	}
 
-	var replicas []*litestream.Replica
-	if r != nil {
-		replicas = []*litestream.Replica{r}
-	} else {
-		replicas = db.Replicas
+	replicas, db, err := loadReplicas(ctx, config, fs.Arg(0), c.replicaName)
+	if err != nil {
+		return err
+	}
+
+	// Determine last time database or WAL was updated.
+	var dbUpdatedAt time.Time
+	if db != nil {
+		if dbUpdatedAt, err = db.UpdatedAt(); err != nil && !os.IsNotExist(err) {
+			return err
+		}
 	}
 
 	// List each generation.
-	w := tabwriter.NewWriter(os.Stdout, 0, 8, 2, ' ', 0)
+	w := tabwriter.NewWriter(c.stdout, 0, 8, 2, ' ', 0)
 	defer w.Flush()
 
 	fmt.Fprintln(w, "name\tgeneration\tlag\tstart\tend")
+
 	for _, r := range replicas {
 		generations, err := r.Client.Generations(ctx)
 		if err != nil {
-			log.Printf("%s: cannot list generations: %s", r.Name(), err)
+			fmt.Fprintf(c.stderr, "%s: cannot list generations: %s", r.Name(), err)
+			ret = errExit // signal error return without printing message
 			continue
 		}
 
@@ -98,26 +85,35 @@ func (c *GenerationsCommand) Run(ctx context.Context, args []string) (err error)
 		for _, generation := range generations {
 			createdAt, updatedAt, err := litestream.GenerationTimeBounds(ctx, r.Client, generation)
 			if err != nil {
-				log.Printf("%s: cannot determine generation time bounds: %s", r.Name(), err)
+				fmt.Fprintf(c.stderr, "%s: cannot determine generation time bounds: %s", r.Name(), err)
+				ret = errExit // signal error return without printing message
 				continue
 			}
 
+			// Calculate lag from database mod time to the replica mod time.
+			// This is ignored if the database mod time is unavailable such as
+			// when specifying the replica URL or if the database file is missing.
+			lag := "-"
+			if !dbUpdatedAt.IsZero() {
+				lag = internal.TruncateDuration(dbUpdatedAt.Sub(updatedAt)).String()
+			}
+
 			fmt.Fprintf(w, "%s\t%s\t%s\t%s\t%s\n",
 				r.Name(),
 				generation,
-				truncateDuration(dbUpdatedAt.Sub(updatedAt)).String(),
+				lag,
 				createdAt.Format(time.RFC3339),
 				updatedAt.Format(time.RFC3339),
 			)
 		}
 	}
 
-	return nil
+	return ret
 }
 
 // Usage prints the help message to STDOUT.
 func (c *GenerationsCommand) Usage() {
-	fmt.Printf(`
+	fmt.Fprintf(c.stdout, `
 The generations command lists all generations for a database or replica. It also
 lists stats about their lag behind the primary database and the time range they
 cover.
@@ -144,29 +140,3 @@ Arguments:
 		DefaultConfigPath(),
 	)
 }
-
-func truncateDuration(d time.Duration) time.Duration {
-	if d < 0 {
-		if d < -10*time.Second {
-			return d.Truncate(time.Second)
-		} else if d < -time.Second {
-			return d.Truncate(time.Second / 10)
-		} else if d < -time.Millisecond {
-			return d.Truncate(time.Millisecond)
-		} else if d < -time.Microsecond {
-			return d.Truncate(time.Microsecond)
-		}
-		return d
-	}
-
-	if d > 10*time.Second {
-		return d.Truncate(time.Second)
-	} else if d > time.Second {
-		return d.Truncate(time.Second / 10)
-	} else if d > time.Millisecond {
-		return d.Truncate(time.Millisecond)
-	} else if d > time.Microsecond {
-		return d.Truncate(time.Microsecond)
-	}
-	return d
-}

cmd/litestream/generations_test.go

@@ -0,0 +1,140 @@
+package main_test
+
+import (
+	"context"
+	"flag"
+	"path/filepath"
+	"strings"
+	"testing"
+
+	"github.com/benbjohnson/litestream/internal/testingutil"
+)
+
+func TestGenerationsCommand(t *testing.T) {
+	t.Run("OK", func(t *testing.T) {
+		testDir := filepath.Join("testdata", "generations", "ok")
+		defer testingutil.Setenv(t, "LITESTREAM_TESTDIR", testDir)()
+
+		m, _, stdout, _ := newMain()
+		if err := m.Run(context.Background(), []string{"generations", "-config", filepath.Join(testDir, "litestream.yml"), filepath.Join(testDir, "db")}); err != nil {
+			t.Fatal(err)
+		} else if got, want := stdout.String(), string(testingutil.MustReadFile(t, filepath.Join(testDir, "stdout"))); got != want {
+			t.Fatalf("stdout=%q, want %q", got, want)
+		}
+	})
+
+	t.Run("ReplicaName", func(t *testing.T) {
+		testDir := filepath.Join("testdata", "generations", "replica-name")
+		defer testingutil.Setenv(t, "LITESTREAM_TESTDIR", testDir)()
+
+		m, _, stdout, _ := newMain()
+		if err := m.Run(context.Background(), []string{"generations", "-config", filepath.Join(testDir, "litestream.yml"), "-replica", "replica1", filepath.Join(testDir, "db")}); err != nil {
+			t.Fatal(err)
+		} else if got, want := stdout.String(), string(testingutil.MustReadFile(t, filepath.Join(testDir, "stdout"))); got != want {
+			t.Fatalf("stdout=%q, want %q", got, want)
+		}
+	})
+
+	t.Run("ReplicaURL", func(t *testing.T) {
+		testDir := filepath.Join(testingutil.Getwd(t), "testdata", "generations", "replica-url")
+		defer testingutil.Setenv(t, "LITESTREAM_TESTDIR", testDir)()
+		replicaURL := "file://" + filepath.ToSlash(testDir) + "/replica"
+
+		m, _, stdout, _ := newMain()
+		if err := m.Run(context.Background(), []string{"generations", replicaURL}); err != nil {
+			t.Fatal(err)
+		} else if got, want := stdout.String(), string(testingutil.MustReadFile(t, filepath.Join(testDir, "stdout"))); got != want {
+			t.Fatalf("stdout=%q, want %q", got, want)
+		}
+	})
+
+	t.Run("NoDatabase", func(t *testing.T) {
+		testDir := filepath.Join("testdata", "generations", "no-database")
+		defer testingutil.Setenv(t, "LITESTREAM_TESTDIR", testDir)()
+
+		m, _, stdout, _ := newMain()
+		if err := m.Run(context.Background(), []string{"generations", "-config", filepath.Join(testDir, "litestream.yml"), filepath.Join(testDir, "db")}); err != nil {
+			t.Fatal(err)
+		} else if got, want := stdout.String(), string(testingutil.MustReadFile(t, filepath.Join(testDir, "stdout"))); got != want {
+			t.Fatalf("stdout=%q, want %q", got, want)
+		}
+	})
+
+	t.Run("ErrDatabaseOrReplicaRequired", func(t *testing.T) {
+		m, _, _, _ := newMain()
+		err := m.Run(context.Background(), []string{"generations"})
+		if err == nil || err.Error() != `database path or replica URL required` {
+			t.Fatalf("unexpected error: %s", err)
+		}
+	})
+
+	t.Run("ErrTooManyArguments", func(t *testing.T) {
+		m, _, _, _ := newMain()
+		err := m.Run(context.Background(), []string{"generations", "abc", "123"})
+		if err == nil || err.Error() != `too many arguments` {
+			t.Fatalf("unexpected error: %s", err)
+		}
+	})
+
+	t.Run("ErrInvalidFlags", func(t *testing.T) {
+		m, _, _, _ := newMain()
+		err := m.Run(context.Background(), []string{"generations", "-no-such-flag"})
+		if err == nil || err.Error() != `flag provided but not defined: -no-such-flag` {
+			t.Fatalf("unexpected error: %s", err)
+		}
+	})
+
+	t.Run("ErrConfigFileNotFound", func(t *testing.T) {
+		m, _, _, _ := newMain()
+		err := m.Run(context.Background(), []string{"generations", "-config", "/no/such/file", "/var/lib/db"})
+		if err == nil || err.Error() != `config file not found: /no/such/file` {
+			t.Fatalf("unexpected error: %s", err)
+		}
+	})
+
+	t.Run("ErrInvalidConfig", func(t *testing.T) {
+		testDir := filepath.Join("testdata", "generations", "invalid-config")
+		m, _, _, _ := newMain()
+		err := m.Run(context.Background(), []string{"generations", "-config", filepath.Join(testDir, "litestream.yml"), "/var/lib/db"})
+		if err == nil || !strings.Contains(err.Error(), `replica path cannot be a url`) {
+			t.Fatalf("unexpected error: %s", err)
+		}
+	})
+
+	t.Run("ErrDatabaseNotFound", func(t *testing.T) {
+		testDir := filepath.Join("testdata", "generations", "database-not-found")
+		defer testingutil.Setenv(t, "LITESTREAM_TESTDIR", testDir)()
+
+		m, _, _, _ := newMain()
+		err := m.Run(context.Background(), []string{"generations", "-config", filepath.Join(testDir, "litestream.yml"), "/no/such/db"})
+		if err == nil || err.Error() != `database not found in config: /no/such/db` {
+			t.Fatalf("unexpected error: %s", err)
+		}
+	})
+
+	t.Run("ErrReplicaNotFound", func(t *testing.T) {
+		testDir := filepath.Join(testingutil.Getwd(t), "testdata", "generations", "replica-not-found")
+		defer testingutil.Setenv(t, "LITESTREAM_TESTDIR", testDir)()
+
+		m, _, _, _ := newMain()
+		err := m.Run(context.Background(), []string{"generations", "-config", filepath.Join(testDir, "litestream.yml"), "-replica", "no_such_replica", filepath.Join(testDir, "db")})
+		if err == nil || err.Error() != `replica "no_such_replica" not found for database "`+filepath.Join(testDir, "db")+`"` {
+			t.Fatalf("unexpected error: %s", err)
+		}
+	})
+
+	t.Run("ErrInvalidReplicaURL", func(t *testing.T) {
+		m, _, _, _ := newMain()
+		err := m.Run(context.Background(), []string{"generations", "xyz://xyz"})
+		if err == nil || !strings.Contains(err.Error(), `unknown replica type in config: "xyz"`) {
+			t.Fatalf("unexpected error: %s", err)
+		}
+	})
+
+	t.Run("Usage", func(t *testing.T) {
+		m, _, _, _ := newMain()
+		if err := m.Run(context.Background(), []string{"generations", "-h"}); err != flag.ErrHelp {
+			t.Fatalf("unexpected error: %s", err)
+		}
+	})
+}

cmd/litestream/main.go

@@ -5,6 +5,7 @@ import (
 	"errors"
 	"flag"
 	"fmt"
+	"io"
 	"io/ioutil"
 	"log"
 	"net/url"
@@ -32,14 +33,14 @@ var (
 	Version = "(development build)"
 )
 
-// errStop is a terminal error for indicating program should quit.
-var errStop = errors.New("stop")
+// errExit is a terminal error for indicating program should quit.
+var errExit = errors.New("exit")
 
 func main() {
 	log.SetFlags(0)
 
-	m := NewMain()
-	if err := m.Run(context.Background(), os.Args[1:]); err == flag.ErrHelp || err == errStop {
+	m := NewMain(os.Stdin, os.Stdout, os.Stderr)
+	if err := m.Run(context.Background(), os.Args[1:]); err == flag.ErrHelp || err == errExit {
 		os.Exit(1)
 	} else if err != nil {
 		log.Println(err)
@@ -48,11 +49,19 @@ func main() {
 }
 
 // Main represents the main program execution.
-type Main struct{}
+type Main struct {
+	stdin  io.Reader
+	stdout io.Writer
+	stderr io.Writer
+}
 
 // NewMain returns a new instance of Main.
-func NewMain() *Main {
-	return &Main{}
+func NewMain(stdin io.Reader, stdout, stderr io.Writer) *Main {
+	return &Main{
+		stdin:  stdin,
+		stdout: stdout,
+		stderr: stderr,
+	}
 }
 
 // Run executes the program.
@@ -75,11 +84,11 @@ func (m *Main) Run(ctx context.Context, args []string) (err error) {
 
 	switch cmd {
 	case "databases":
-		return (&DatabasesCommand{}).Run(ctx, args)
+		return NewDatabasesCommand(m.stdin, m.stdout, m.stderr).Run(ctx, args)
 	case "generations":
-		return (&GenerationsCommand{}).Run(ctx, args)
+		return NewGenerationsCommand(m.stdin, m.stdout, m.stderr).Run(ctx, args)
 	case "replicate":
-		c := NewReplicateCommand()
+		c := NewReplicateCommand(m.stdin, m.stdout, m.stderr)
 		if err := c.ParseFlags(ctx, args); err != nil {
 			return err
 		}
@@ -96,21 +105,21 @@ func (m *Main) Run(ctx context.Context, args []string) (err error) {
 		// Wait for signal to stop program.
 		select {
 		case <-ctx.Done():
-			fmt.Println("context done, litestream shutting down")
+			fmt.Fprintln(m.stdout, "context done, litestream shutting down")
 		case err = <-c.execCh:
 			cancel()
-			fmt.Println("subprocess exited, litestream shutting down")
+			fmt.Fprintln(m.stdout, "subprocess exited, litestream shutting down")
 		case sig := <-signalCh:
 			cancel()
-			fmt.Println("signal received, litestream shutting down")
+			fmt.Fprintln(m.stdout, "signal received, litestream shutting down")
 
 			if c.cmd != nil {
-				fmt.Println("sending signal to exec process")
+				fmt.Fprintln(m.stdout, "sending signal to exec process")
 				if err := c.cmd.Process.Signal(sig); err != nil {
 					return fmt.Errorf("cannot signal exec process: %w", err)
 				}
 
-				fmt.Println("waiting for exec process to close")
+				fmt.Fprintln(m.stdout, "waiting for exec process to close")
 				if err := <-c.execCh; err != nil && !strings.HasPrefix(err.Error(), "signal:") {
 					return fmt.Errorf("cannot wait for exec process: %w", err)
 				}
@@ -121,17 +130,17 @@ func (m *Main) Run(ctx context.Context, args []string) (err error) {
 		if e := c.Close(); e != nil && err == nil {
 			err = e
 		}
-		fmt.Println("litestream shut down")
+		fmt.Fprintln(m.stdout, "litestream shut down")
 		return err
 
 	case "restore":
-		return NewRestoreCommand().Run(ctx, args)
+		return NewRestoreCommand(m.stdin, m.stdout, m.stderr).Run(ctx, args)
 	case "snapshots":
-		return (&SnapshotsCommand{}).Run(ctx, args)
+		return NewSnapshotsCommand(m.stdin, m.stdout, m.stderr).Run(ctx, args)
 	case "version":
-		return (&VersionCommand{}).Run(ctx, args)
+		return NewVersionCommand(m.stdin, m.stdout, m.stderr).Run(ctx, args)
 	case "wal":
-		return (&WALCommand{}).Run(ctx, args)
+		return NewWALCommand(m.stdin, m.stdout, m.stderr).Run(ctx, args)
 	default:
 		if cmd == "" || cmd == "help" || strings.HasPrefix(cmd, "-") {
 			m.Usage()
@@ -143,7 +152,7 @@ func (m *Main) Run(ctx context.Context, args []string) (err error) {
 
 // Usage prints the help screen to STDOUT.
 func (m *Main) Usage() {
-	fmt.Println(`
+	fmt.Fprintln(m.stdout, `
 litestream is a tool for replicating SQLite databases.
 
 Usage:
@@ -210,9 +219,15 @@ func (c *Config) DBConfig(path string) *DBConfig {
 
 // ReadConfigFile unmarshals config from filename. Expands path if needed.
 // If expandEnv is true then environment variables are expanded in the config.
+// If filename is blank then the default config path is used.
 func ReadConfigFile(filename string, expandEnv bool) (_ Config, err error) {
 	config := DefaultConfig()
 
+	useDefaultPath := filename == ""
+	if useDefaultPath {
+		filename = DefaultConfigPath()
+	}
+
 	// Expand filename, if necessary.
 	filename, err = expand(filename)
 	if err != nil {
@@ -220,8 +235,12 @@ func ReadConfigFile(filename string, expandEnv bool) (_ Config, err error) {
 	}
 
 	// Read configuration.
+	// Do not return an error if using default path and file is missing.
 	buf, err := ioutil.ReadFile(filename)
 	if os.IsNotExist(err) {
+		if useDefaultPath {
+			return config, nil
+		}
 		return config, fmt.Errorf("config file not found: %s", filename)
 	} else if err != nil {
 		return config, err
@@ -354,7 +373,7 @@ func NewReplicaFromConfig(c *ReplicaConfig, db *litestream.DB) (_ *litestream.Re
 	}
 
 	// Build and set client on replica.
-	switch c.ReplicaType() {
+	switch typ := c.ReplicaType(); typ {
 	case "file":
 		if r.Client, err = newFileReplicaClientFromConfig(c, r); err != nil {
 			return nil, err
@@ -376,7 +395,7 @@ func NewReplicaFromConfig(c *ReplicaConfig, db *litestream.DB) (_ *litestream.Re
 			return nil, err
 		}
 	default:
-		return nil, fmt.Errorf("unknown replica type in config: %q", c.Type)
+		return nil, fmt.Errorf("unknown replica type in config: %q", typ)
 	}
 
 	return r, nil
@@ -714,3 +733,45 @@ func (v *indexVar) Set(s string) error {
 	*v = indexVar(i)
 	return nil
 }
+
+// loadReplicas returns a list of replicas to use based on CLI flags. Filters
+// by replicaName, if not blank. The DB is returned if pathOrURL is not a replica URL.
+func loadReplicas(ctx context.Context, config Config, pathOrURL, replicaName string) ([]*litestream.Replica, *litestream.DB, error) {
+	// Build a replica based on URL, if specified.
+	if isURL(pathOrURL) {
+		r, err := NewReplicaFromConfig(&ReplicaConfig{
+			URL:             pathOrURL,
+			AccessKeyID:     config.AccessKeyID,
+			SecretAccessKey: config.SecretAccessKey,
+		}, nil)
+		if err != nil {
+			return nil, nil, err
+		}
+		return []*litestream.Replica{r}, nil, nil
+	}
+
+	// Otherwise use replicas from the database configuration file.
+	path, err := expand(pathOrURL)
+	if err != nil {
+		return nil, nil, err
+	}
+	dbc := config.DBConfig(path)
+	if dbc == nil {
+		return nil, nil, fmt.Errorf("database not found in config: %s", path)
+	}
+	db, err := NewDBFromConfig(dbc)
+	if err != nil {
+		return nil, nil, err
+	}
+
+	// Filter by replica, if specified.
+	if replicaName != "" {
+		r := db.Replica(replicaName)
+		if r == nil {
+			return nil, nil, fmt.Errorf("replica %q not found for database %q", replicaName, db.Path())
+		}
+		return []*litestream.Replica{r}, db, nil
+	}
+
+	return db.Replicas, db, nil
+}

cmd/litestream/main_test.go

@@ -1,6 +1,8 @@
 package main_test
 
 import (
+	"bytes"
+	"io"
 	"io/ioutil"
 	"log"
 	"os"
@@ -180,3 +182,17 @@ func TestNewGCSReplicaFromConfig(t *testing.T) {
 		t.Fatalf("Path=%s, want %s", got, want)
 	}
 }
+
+// newMain returns a new instance of Main and associated buffers.
+func newMain() (m *main.Main, stdin, stdout, stderr *bytes.Buffer) {
+	stdin, stdout, stderr = &bytes.Buffer{}, &bytes.Buffer{}, &bytes.Buffer{}
+
+	// Split stdout/stderr to terminal if verbose flag set.
+	out, err := io.Writer(stdout), io.Writer(stderr)
+	if testing.Verbose() {
+		out = io.MultiWriter(out, os.Stdout)
+		err = io.MultiWriter(err, os.Stderr)
+	}
+
+	return main.NewMain(stdin, out, err), stdin, stdout, stderr
+}

cmd/litestream/main_windows.go

@@ -1,3 +1,4 @@
+//go:build windows
 // +build windows
 
 package main
@@ -41,7 +42,7 @@ func runWindowsService(ctx context.Context) error {
 	log.Print("Litestream service starting")
 
 	if err := svc.Run(serviceName, &windowsService{ctx: ctx}); err != nil {
-		return errStop
+		return errExit
 	}
 
 	log.Print("Litestream service stopped")

cmd/litestream/replicate.go

@@ -4,6 +4,7 @@ import (
 	"context"
 	"flag"
 	"fmt"
+	"io"
 	"log"
 	"net"
 	"net/http"
@@ -22,6 +23,10 @@ import (
 
 // ReplicateCommand represents a command that continuously replicates SQLite databases.
 type ReplicateCommand struct {
+	stdin  io.Reader
+	stdout io.Writer
+	stderr io.Writer
+
 	configPath  string
 	noExpandEnv bool
 
@@ -34,8 +39,13 @@ type ReplicateCommand struct {
 	DBs []*litestream.DB
 }
 
-func NewReplicateCommand() *ReplicateCommand {
+// NewReplicateCommand returns a new instance of ReplicateCommand.
+func NewReplicateCommand(stdin io.Reader, stdout, stderr io.Writer) *ReplicateCommand {
 	return &ReplicateCommand{
+		stdin:  stdin,
+		stdout: stdout,
+		stderr: stderr,
+
 		execCh: make(chan error),
 	}
 }
@@ -181,7 +191,7 @@ func (c *ReplicateCommand) Close() (err error) {
 
 // Usage prints the help screen to STDOUT.
 func (c *ReplicateCommand) Usage() {
-	fmt.Printf(`
+	fmt.Fprintf(c.stdout, `
 The replicate command starts a server to monitor & replicate databases. 
 You can specify your database & replicas in a configuration file or you can
 replicate a single database file by specifying its path and its replicas in the

cmd/litestream/replicate_test.go

@@ -13,7 +13,6 @@ import (
 	"testing"
 	"time"
 
-	main "github.com/benbjohnson/litestream/cmd/litestream"
 	"golang.org/x/sync/errgroup"
 )
 
@@ -82,7 +81,8 @@ dbs:
 
 	// Replicate database unless the context is canceled.
 	g.Go(func() error {
-		return main.NewMain().Run(mainctx, []string{"replicate", "-config", configPath})
+		m, _, _, _ := newMain()
+		return m.Run(mainctx, []string{"replicate", "-config", configPath})
 	})
 
 	if err := g.Wait(); err != nil {
@@ -94,7 +94,8 @@ dbs:
 	chksum0 := mustChecksum(t, dbPath)
 
 	// Restore to another path.
-	if err := main.NewMain().Run(context.Background(), []string{"restore", "-config", configPath, "-o", restorePath, dbPath}); err != nil && !errors.Is(err, context.Canceled) {
+	m, _, _, _ := newMain()
+	if err := m.Run(context.Background(), []string{"restore", "-config", configPath, "-o", restorePath, dbPath}); err != nil && !errors.Is(err, context.Canceled) {
 		t.Fatal(err)
 	}
 

cmd/litestream/restore.go

@@ -5,6 +5,7 @@ import (
 	"errors"
 	"flag"
 	"fmt"
+	"io"
 	"log"
 	"os"
 	"path/filepath"
@@ -15,6 +16,10 @@ import (
 
 // RestoreCommand represents a command to restore a database from a backup.
 type RestoreCommand struct {
+	stdin  io.Reader
+	stdout io.Writer
+	stderr io.Writer
+
 	snapshotIndex int // index of snapshot to start from
 
 	// CLI options
@@ -29,8 +34,13 @@ type RestoreCommand struct {
 	opt             litestream.RestoreOptions
 }
 
-func NewRestoreCommand() *RestoreCommand {
+// NewRestoreCommand returns a new instance of RestoreCommand.
+func NewRestoreCommand(stdin io.Reader, stdout, stderr io.Writer) *RestoreCommand {
 	return &RestoreCommand{
+		stdin:  stdin,
+		stdout: stdout,
+		stderr: stderr,
+
 		targetIndex: -1,
 		opt:         litestream.NewRestoreOptions(),
 	}
@@ -55,31 +65,39 @@ func (c *RestoreCommand) Run(ctx context.Context, args []string) (err error) {
 	} else if fs.NArg() > 1 {
 		return fmt.Errorf("too many arguments")
 	}
-	arg := fs.Arg(0)
+	pathOrURL := fs.Arg(0)
 
 	// Ensure a generation is specified if target index is specified.
 	if c.targetIndex != -1 && c.generation == "" {
-		return fmt.Errorf("must specify -generation when using -index flag")
+		return fmt.Errorf("must specify -generation flag when using -index flag")
 	}
 
 	// Default to original database path if output path not specified.
-	if !isURL(arg) && c.outputPath == "" {
-		c.outputPath = arg
+	if !isURL(pathOrURL) && c.outputPath == "" {
+		c.outputPath = pathOrURL
 	}
 
 	// Exit successfully if the output file already exists and flag is set.
-	if _, err := os.Stat(c.outputPath); !os.IsNotExist(err) && c.ifDBNotExists {
-		fmt.Println("database already exists, skipping")
-		return nil
+	if _, err := os.Stat(c.outputPath); os.IsNotExist(err) {
+		// file doesn't exist, continue
+	} else if err != nil {
+		return err
+	} else if err == nil {
+		if c.ifDBNotExists {
+			fmt.Fprintln(c.stdout, "database already exists, skipping")
+			return nil
+		}
+		return fmt.Errorf("output file already exists: %s", c.outputPath)
 	}
 
-	// Create parent directory if it doesn't already exist.
-	if err := os.MkdirAll(filepath.Dir(c.outputPath), 0700); err != nil {
-		return fmt.Errorf("cannot create parent directory: %w", err)
+	// Load configuration.
+	config, err := ReadConfigFile(c.configPath, !c.noExpandEnv)
+	if err != nil {
+		return err
 	}
 
 	// Build replica from either a URL or config.
-	r, err := c.loadReplica(ctx, arg)
+	r, err := c.loadReplica(ctx, config, pathOrURL)
 	if err != nil {
 		return err
 	}
@@ -90,7 +108,7 @@ func (c *RestoreCommand) Run(ctx context.Context, args []string) (err error) {
 			// Return an error if no matching targets found.
 			// If optional flag set, return success. Useful for automated recovery.
 			if c.ifReplicaExists {
-				fmt.Println("no matching backups found")
+				fmt.Fprintln(c.stdout, "no matching backups found, skipping")
 				return nil
 			}
 			return fmt.Errorf("no matching backups found")
@@ -112,47 +130,42 @@ func (c *RestoreCommand) Run(ctx context.Context, args []string) (err error) {
 		return fmt.Errorf("cannot find snapshot index: %w", err)
 	}
 
-	c.opt.Logger = log.New(os.Stderr, "", log.LstdFlags|log.Lmicroseconds)
+	// Create parent directory if it doesn't already exist.
+	if err := os.MkdirAll(filepath.Dir(c.outputPath), 0700); err != nil {
+		return fmt.Errorf("cannot create parent directory: %w", err)
+	}
+
+	c.opt.Logger = log.New(c.stdout, "", log.LstdFlags|log.Lmicroseconds)
 
 	return litestream.Restore(ctx, r.Client, c.outputPath, c.generation, c.snapshotIndex, c.targetIndex, c.opt)
 }
 
-func (c *RestoreCommand) loadReplica(ctx context.Context, arg string) (*litestream.Replica, error) {
+func (c *RestoreCommand) loadReplica(ctx context.Context, config Config, arg string) (*litestream.Replica, error) {
 	if isURL(arg) {
-		return c.loadReplicaFromURL(ctx, arg)
+		return c.loadReplicaFromURL(ctx, config, arg)
 	}
-	return c.loadReplicaFromConfig(ctx, arg)
+	return c.loadReplicaFromConfig(ctx, config, arg)
 }
 
 // loadReplicaFromURL creates a replica & updates the restore options from a replica URL.
-func (c *RestoreCommand) loadReplicaFromURL(ctx context.Context, replicaURL string) (*litestream.Replica, error) {
-	if c.configPath != "" {
-		return nil, fmt.Errorf("cannot specify a replica URL and the -config flag")
-	} else if c.replicaName != "" {
-		return nil, fmt.Errorf("cannot specify a replica URL and the -replica flag")
+func (c *RestoreCommand) loadReplicaFromURL(ctx context.Context, config Config, replicaURL string) (*litestream.Replica, error) {
+	if c.replicaName != "" {
+		return nil, fmt.Errorf("cannot specify both the replica URL and the -replica flag")
 	} else if c.outputPath == "" {
-		return nil, fmt.Errorf("output path required")
+		return nil, fmt.Errorf("output path required when using a replica URL")
 	}
 
 	syncInterval := litestream.DefaultSyncInterval
 	return NewReplicaFromConfig(&ReplicaConfig{
-		URL:          replicaURL,
-		SyncInterval: &syncInterval,
+		URL:             replicaURL,
+		AccessKeyID:     config.AccessKeyID,
+		SecretAccessKey: config.SecretAccessKey,
+		SyncInterval:    &syncInterval,
 	}, nil)
 }
 
 // loadReplicaFromConfig returns replicas based on the specific config path.
-func (c *RestoreCommand) loadReplicaFromConfig(ctx context.Context, dbPath string) (*litestream.Replica, error) {
-	if c.configPath == "" {
-		c.configPath = DefaultConfigPath()
-	}
-
-	// Load configuration.
-	config, err := ReadConfigFile(c.configPath, !c.noExpandEnv)
-	if err != nil {
-		return nil, err
-	}
-
+func (c *RestoreCommand) loadReplicaFromConfig(ctx context.Context, config Config, dbPath string) (_ *litestream.Replica, err error) {
 	// Lookup database from configuration file by path.
 	if dbPath, err = expand(dbPath); err != nil {
 		return nil, err
@@ -184,7 +197,7 @@ func (c *RestoreCommand) loadReplicaFromConfig(ctx context.Context, dbPath strin
 
 	// A replica must be specified when restoring a specific generation with multiple replicas.
 	if c.generation != "" {
-		return nil, fmt.Errorf("must specify -replica when restoring from a specific generation")
+		return nil, fmt.Errorf("must specify -replica flag when restoring from a specific generation")
 	}
 
 	// Determine latest replica to restore from.
@@ -197,7 +210,7 @@ func (c *RestoreCommand) loadReplicaFromConfig(ctx context.Context, dbPath strin
 
 // Usage prints the help screen to STDOUT.
 func (c *RestoreCommand) Usage() {
-	fmt.Printf(`
+	fmt.Fprintf(c.stdout, `
 The restore command recovers a database from a previous snapshot and WAL.
 
 Usage:

cmd/litestream/restore_test.go

@@ -0,0 +1,330 @@
+package main_test
+
+import (
+	"context"
+	"flag"
+	"os"
+	"path/filepath"
+	"strings"
+	"testing"
+
+	"github.com/benbjohnson/litestream/internal/testingutil"
+)
+
+func TestRestoreCommand(t *testing.T) {
+	t.Run("OK", func(t *testing.T) {
+		testDir := filepath.Join("testdata", "restore", "ok")
+		defer testingutil.Setenv(t, "LITESTREAM_TESTDIR", testDir)()
+		tempDir := t.TempDir()
+
+		m, _, stdout, stderr := newMain()
+		if err := m.Run(context.Background(), []string{"restore", "-config", filepath.Join(testDir, "litestream.yml"), "-o", filepath.Join(tempDir, "db"), filepath.Join(testDir, "db")}); err != nil {
+			t.Fatal(err)
+		} else if got, want := stderr.String(), ""; got != want {
+			t.Fatalf("stderr=%q, want %q", got, want)
+		}
+
+		// STDOUT has timing info so we need to grep per line.
+		lines := strings.Split(stdout.String(), "\n")
+		for i, substr := range []string{
+			`restoring snapshot 0000000000000000/00000000 to ` + filepath.Join(tempDir, "db.tmp"),
+			`applied wal 0000000000000000/00000000 elapsed=`,
+			`applied wal 0000000000000000/00000001 elapsed=`,
+			`applied wal 0000000000000000/00000002 elapsed=`,
+			`renaming database from temporary location`,
+		} {
+			if !strings.Contains(lines[i], substr) {
+				t.Fatalf("stdout: unexpected line %d:\n%s", i+1, stdout)
+			}
+		}
+	})
+
+	t.Run("ReplicaName", func(t *testing.T) {
+		testDir := filepath.Join("testdata", "restore", "replica-name")
+		defer testingutil.Setenv(t, "LITESTREAM_TESTDIR", testDir)()
+		tempDir := t.TempDir()
+
+		m, _, stdout, stderr := newMain()
+		if err := m.Run(context.Background(), []string{"restore", "-config", filepath.Join(testDir, "litestream.yml"), "-o", filepath.Join(tempDir, "db"), "-replica", "replica1", filepath.Join(testDir, "db")}); err != nil {
+			t.Fatal(err)
+		} else if got, want := stderr.String(), ""; got != want {
+			t.Fatalf("stderr=%q, want %q", got, want)
+		}
+
+		// STDOUT has timing info so we need to grep per line.
+		lines := strings.Split(stdout.String(), "\n")
+		for i, substr := range []string{
+			`restoring snapshot 0000000000000001/00000001 to ` + filepath.Join(tempDir, "db.tmp"),
+			`no wal files found, snapshot only`,
+			`renaming database from temporary location`,
+		} {
+			if !strings.Contains(lines[i], substr) {
+				t.Fatalf("stdout: unexpected line %d:\n%s", i+1, stdout)
+			}
+		}
+	})
+
+	t.Run("ReplicaURL", func(t *testing.T) {
+		testDir := filepath.Join(testingutil.Getwd(t), "testdata", "restore", "replica-url")
+		tempDir := t.TempDir()
+		replicaURL := "file://" + filepath.ToSlash(testDir) + "/replica"
+
+		m, _, stdout, stderr := newMain()
+		if err := m.Run(context.Background(), []string{"restore", "-o", filepath.Join(tempDir, "db"), replicaURL}); err != nil {
+			t.Fatal(err)
+		} else if got, want := stderr.String(), ""; got != want {
+			t.Fatalf("stderr=%q, want %q", got, want)
+		}
+
+		lines := strings.Split(stdout.String(), "\n")
+		for i, substr := range []string{
+			`restoring snapshot 0000000000000000/00000000 to ` + filepath.Join(tempDir, "db.tmp"),
+			`no wal files found, snapshot only`,
+			`renaming database from temporary location`,
+		} {
+			if !strings.Contains(lines[i], substr) {
+				t.Fatalf("stdout: unexpected line %d:\n%s", i+1, stdout)
+			}
+		}
+	})
+
+	t.Run("LatestReplica", func(t *testing.T) {
+		testDir := filepath.Join("testdata", "restore", "latest-replica")
+		defer testingutil.Setenv(t, "LITESTREAM_TESTDIR", testDir)()
+		tempDir := t.TempDir()
+
+		m, _, stdout, stderr := newMain()
+		if err := m.Run(context.Background(), []string{"restore", "-config", filepath.Join(testDir, "litestream.yml"), "-o", filepath.Join(tempDir, "db"), filepath.Join(testDir, "db")}); err != nil {
+			t.Fatal(err)
+		} else if got, want := stderr.String(), ""; got != want {
+			t.Fatalf("stderr=%q, want %q", got, want)
+		}
+
+		lines := strings.Split(stdout.String(), "\n")
+		for i, substr := range []string{
+			`restoring snapshot 0000000000000001/00000000 to ` + filepath.Join(tempDir, "db.tmp"),
+			`no wal files found, snapshot only`,
+			`renaming database from temporary location`,
+		} {
+			if !strings.Contains(lines[i], substr) {
+				t.Fatalf("stdout: unexpected line %d:\n%s", i+1, stdout)
+			}
+		}
+	})
+
+	t.Run("IfDBNotExistsFlag", func(t *testing.T) {
+		testDir := filepath.Join("testdata", "restore", "if-db-not-exists-flag")
+		defer testingutil.Setenv(t, "LITESTREAM_TESTDIR", testDir)()
+
+		m, _, stdout, _ := newMain()
+		err := m.Run(context.Background(), []string{"restore", "-config", filepath.Join(testDir, "litestream.yml"), "-if-db-not-exists", filepath.Join(testDir, "db")})
+		if err != nil {
+			t.Fatal(err)
+		} else if got, want := stdout.String(), string(testingutil.MustReadFile(t, filepath.Join(testDir, "stdout"))); got != want {
+			t.Fatalf("stdout=%q, want %q", got, want)
+		}
+	})
+
+	t.Run("IfReplicaExists", func(t *testing.T) {
+		testDir := filepath.Join("testdata", "restore", "if-replica-exists-flag")
+		defer testingutil.Setenv(t, "LITESTREAM_TESTDIR", testDir)()
+
+		m, _, stdout, _ := newMain()
+		err := m.Run(context.Background(), []string{"restore", "-config", filepath.Join(testDir, "litestream.yml"), "-if-replica-exists", filepath.Join(testDir, "db")})
+		if err != nil {
+			t.Fatal(err)
+		} else if got, want := stdout.String(), string(testingutil.MustReadFile(t, filepath.Join(testDir, "stdout"))); got != want {
+			t.Fatalf("stdout=%q, want %q", got, want)
+		}
+	})
+
+	t.Run("ErrNoBackups", func(t *testing.T) {
+		testDir := filepath.Join("testdata", "restore", "no-backups")
+		defer testingutil.Setenv(t, "LITESTREAM_TESTDIR", testDir)()
+		tempDir := t.TempDir()
+
+		m, _, stdout, stderr := newMain()
+		err := m.Run(context.Background(), []string{"restore", "-config", filepath.Join(testDir, "litestream.yml"), "-o", filepath.Join(tempDir, "db"), filepath.Join(testDir, "db")})
+		if err == nil || err.Error() != `no matching backups found` {
+			t.Fatalf("unexpected error: %s", err)
+		} else if got, want := stdout.String(), string(testingutil.MustReadFile(t, filepath.Join(testDir, "stdout"))); got != want {
+			t.Fatalf("stdout=%q, want %q", got, want)
+		} else if got, want := stderr.String(), string(testingutil.MustReadFile(t, filepath.Join(testDir, "stderr"))); got != want {
+			t.Fatalf("stderr=%q, want %q", got, want)
+		}
+	})
+
+	t.Run("ErrNoGeneration", func(t *testing.T) {
+		testDir := filepath.Join("testdata", "restore", "no-generation")
+		defer testingutil.Setenv(t, "LITESTREAM_TESTDIR", testDir)()
+
+		m, _, _, _ := newMain()
+		err := m.Run(context.Background(), []string{"restore", "-config", filepath.Join(testDir, "litestream.yml"), filepath.Join(testDir, "db")})
+		if err == nil || err.Error() != `no matching backups found` {
+			t.Fatalf("unexpected error: %s", err)
+		}
+	})
+
+	t.Run("ErrOutputPathExists", func(t *testing.T) {
+		testDir := filepath.Join("testdata", "restore", "output-path-exists")
+		defer testingutil.Setenv(t, "LITESTREAM_TESTDIR", testDir)()
+
+		m, _, _, _ := newMain()
+		err := m.Run(context.Background(), []string{"restore", "-config", filepath.Join(testDir, "litestream.yml"), filepath.Join(testDir, "db")})
+		if err == nil || err.Error() != `output file already exists: `+filepath.Join(testDir, "db") {
+			t.Fatalf("unexpected error: %s", err)
+		}
+	})
+
+	t.Run("ErrDatabaseOrReplicaRequired", func(t *testing.T) {
+		m, _, _, _ := newMain()
+		err := m.Run(context.Background(), []string{"restore"})
+		if err == nil || err.Error() != `database path or replica URL required` {
+			t.Fatalf("unexpected error: %s", err)
+		}
+	})
+
+	t.Run("ErrTooManyArguments", func(t *testing.T) {
+		m, _, _, _ := newMain()
+		err := m.Run(context.Background(), []string{"restore", "abc", "123"})
+		if err == nil || err.Error() != `too many arguments` {
+			t.Fatalf("unexpected error: %s", err)
+		}
+	})
+
+	t.Run("ErrInvalidFlags", func(t *testing.T) {
+		m, _, _, _ := newMain()
+		err := m.Run(context.Background(), []string{"restore", "-no-such-flag"})
+		if err == nil || err.Error() != `flag provided but not defined: -no-such-flag` {
+			t.Fatalf("unexpected error: %s", err)
+		}
+	})
+
+	t.Run("ErrIndexFlagOnly", func(t *testing.T) {
+		m, _, _, _ := newMain()
+		err := m.Run(context.Background(), []string{"restore", "-index", "0", "/var/lib/db"})
+		if err == nil || err.Error() != `must specify -generation flag when using -index flag` {
+			t.Fatalf("unexpected error: %s", err)
+		}
+	})
+
+	t.Run("ErrConfigFileNotFound", func(t *testing.T) {
+		m, _, _, _ := newMain()
+		err := m.Run(context.Background(), []string{"restore", "-config", "/no/such/file", "/var/lib/db"})
+		if err == nil || err.Error() != `config file not found: /no/such/file` {
+			t.Fatalf("unexpected error: %s", err)
+		}
+	})
+
+	t.Run("ErrInvalidConfig", func(t *testing.T) {
+		testDir := filepath.Join("testdata", "restore", "invalid-config")
+		m, _, _, _ := newMain()
+		err := m.Run(context.Background(), []string{"restore", "-config", filepath.Join(testDir, "litestream.yml"), "/var/lib/db"})
+		if err == nil || !strings.Contains(err.Error(), `replica path cannot be a url`) {
+			t.Fatalf("unexpected error: %s", err)
+		}
+	})
+
+	t.Run("ErrMkdir", func(t *testing.T) {
+		tempDir := t.TempDir()
+		if err := os.Mkdir(filepath.Join(tempDir, "noperm"), 0000); err != nil {
+			t.Fatal(err)
+		}
+
+		m, _, _, _ := newMain()
+		err := m.Run(context.Background(), []string{"restore", "-o", filepath.Join(tempDir, "noperm", "subdir", "db"), "/var/lib/db"})
+		if err == nil || !strings.Contains(err.Error(), `permission denied`) {
+			t.Fatalf("unexpected error: %s", err)
+		}
+	})
+
+	t.Run("ErrNoOutputPathWithReplicaURL", func(t *testing.T) {
+		m, _, _, _ := newMain()
+		err := m.Run(context.Background(), []string{"restore", "file://path/to/replica"})
+		if err == nil || err.Error() != `output path required when using a replica URL` {
+			t.Fatalf("unexpected error: %s", err)
+		}
+	})
+
+	t.Run("ErrReplicaNameWithReplicaURL", func(t *testing.T) {
+		m, _, _, _ := newMain()
+		err := m.Run(context.Background(), []string{"restore", "-replica", "replica0", "file://path/to/replica"})
+		if err == nil || err.Error() != `cannot specify both the replica URL and the -replica flag` {
+			t.Fatalf("unexpected error: %s", err)
+		}
+	})
+
+	t.Run("ErrInvalidReplicaURL", func(t *testing.T) {
+		m, _, _, _ := newMain()
+		err := m.Run(context.Background(), []string{"restore", "-o", "/tmp/db", "xyz://xyz"})
+		if err == nil || err.Error() != `unknown replica type in config: "xyz"` {
+			t.Fatalf("unexpected error: %s", err)
+		}
+	})
+
+	t.Run("ErrDatabaseNotFound", func(t *testing.T) {
+		testDir := filepath.Join("testdata", "restore", "database-not-found")
+		defer testingutil.Setenv(t, "LITESTREAM_TESTDIR", testDir)()
+
+		m, _, _, _ := newMain()
+		err := m.Run(context.Background(), []string{"restore", "-config", filepath.Join(testDir, "litestream.yml"), "/no/such/db"})
+		if err == nil || err.Error() != `database not found in config: /no/such/db` {
+			t.Fatalf("unexpected error: %s", err)
+		}
+	})
+
+	t.Run("ErrNoReplicas", func(t *testing.T) {
+		testDir := filepath.Join("testdata", "restore", "no-replicas")
+		defer testingutil.Setenv(t, "LITESTREAM_TESTDIR", testDir)()
+		tempDir := t.TempDir()
+
+		m, _, _, _ := newMain()
+		err := m.Run(context.Background(), []string{"restore", "-config", filepath.Join(testDir, "litestream.yml"), "-o", filepath.Join(tempDir, "db"), filepath.Join(testDir, "db")})
+		if err == nil || err.Error() != `database has no replicas: `+filepath.Join(testingutil.Getwd(t), testDir, "db") {
+			t.Fatalf("unexpected error: %s", err)
+		}
+	})
+
+	t.Run("ErrReplicaNotFound", func(t *testing.T) {
+		testDir := filepath.Join("testdata", "restore", "replica-not-found")
+		defer testingutil.Setenv(t, "LITESTREAM_TESTDIR", testDir)()
+		tempDir := t.TempDir()
+
+		m, _, _, _ := newMain()
+		err := m.Run(context.Background(), []string{"restore", "-config", filepath.Join(testDir, "litestream.yml"), "-o", filepath.Join(tempDir, "db"), "-replica", "no_such_replica", filepath.Join(testDir, "db")})
+		if err == nil || err.Error() != `replica "no_such_replica" not found` {
+			t.Fatalf("unexpected error: %s", err)
+		}
+	})
+
+	t.Run("ErrGenerationWithNoReplicaName", func(t *testing.T) {
+		testDir := filepath.Join("testdata", "restore", "generation-with-no-replica")
+		defer testingutil.Setenv(t, "LITESTREAM_TESTDIR", testDir)()
+		tempDir := t.TempDir()
+
+		m, _, _, _ := newMain()
+		err := m.Run(context.Background(), []string{"restore", "-config", filepath.Join(testDir, "litestream.yml"), "-o", filepath.Join(tempDir, "db"), "-generation", "0000000000000000", filepath.Join(testDir, "db")})
+		if err == nil || err.Error() != `must specify -replica flag when restoring from a specific generation` {
+			t.Fatalf("unexpected error: %s", err)
+		}
+	})
+
+	t.Run("ErrNoSnapshotsAvailable", func(t *testing.T) {
+		testDir := filepath.Join("testdata", "restore", "no-snapshots")
+		defer testingutil.Setenv(t, "LITESTREAM_TESTDIR", testDir)()
+		tempDir := t.TempDir()
+
+		m, _, _, _ := newMain()
+		err := m.Run(context.Background(), []string{"restore", "-config", filepath.Join(testDir, "litestream.yml"), "-o", filepath.Join(tempDir, "db"), "-generation", "0000000000000000", filepath.Join(testDir, "db")})
+		if err == nil || err.Error() != `cannot determine latest index in generation "0000000000000000": no snapshots available` {
+			t.Fatalf("unexpected error: %s", err)
+		}
+	})
+
+	t.Run("Usage", func(t *testing.T) {
+		m, _, _, _ := newMain()
+		if err := m.Run(context.Background(), []string{"restore", "-h"}); err != flag.ErrHelp {
+			t.Fatalf("unexpected error: %s", err)
+		}
+	})
+}

cmd/litestream/snapshots.go

@@ -4,8 +4,8 @@ import (
 	"context"
 	"flag"
 	"fmt"
+	"io"
 	"log"
-	"os"
 	"sort"
 	"text/tabwriter"
 	"time"
@@ -15,99 +15,89 @@ import (
 
 // SnapshotsCommand represents a command to list snapshots for a command.
 type SnapshotsCommand struct {
+	stdin  io.Reader
+	stdout io.Writer
+	stderr io.Writer
+
 	configPath  string
 	noExpandEnv bool
+
+	replicaName string
+}
+
+// NewSnapshotsCommand returns a new instance of SnapshotsCommand.
+func NewSnapshotsCommand(stdin io.Reader, stdout, stderr io.Writer) *SnapshotsCommand {
+	return &SnapshotsCommand{
+		stdin:  stdin,
+		stdout: stdout,
+		stderr: stderr,
+	}
 }
 
 // Run executes the command.
-func (c *SnapshotsCommand) Run(ctx context.Context, args []string) (err error) {
+func (c *SnapshotsCommand) Run(ctx context.Context, args []string) (ret error) {
 	fs := flag.NewFlagSet("litestream-snapshots", flag.ContinueOnError)
 	registerConfigFlag(fs, &c.configPath, &c.noExpandEnv)
-	replicaName := fs.String("replica", "", "replica name")
+	fs.StringVar(&c.replicaName, "replica", "", "replica name")
 	fs.Usage = c.Usage
 	if err := fs.Parse(args); err != nil {
 		return err
 	} else if fs.NArg() == 0 || fs.Arg(0) == "" {
-		return fmt.Errorf("database path required")
+		return fmt.Errorf("database path or replica URL required")
 	} else if fs.NArg() > 1 {
 		return fmt.Errorf("too many arguments")
 	}
 
-	var db *litestream.DB
-	var r *litestream.Replica
-	if isURL(fs.Arg(0)) {
-		if c.configPath != "" {
-			return fmt.Errorf("cannot specify a replica URL and the -config flag")
-		}
-		if r, err = NewReplicaFromConfig(&ReplicaConfig{URL: fs.Arg(0)}, nil); err != nil {
-			return err
-		}
-	} else {
-		if c.configPath == "" {
-			c.configPath = DefaultConfigPath()
-		}
+	// Load configuration.
+	config, err := ReadConfigFile(c.configPath, !c.noExpandEnv)
+	if err != nil {
+		return err
+	}
 
-		// Load configuration.
-		config, err := ReadConfigFile(c.configPath, !c.noExpandEnv)
+	// Determine list of replicas to pull snapshots from.
+	replicas, _, err := loadReplicas(ctx, config, fs.Arg(0), c.replicaName)
+	if err != nil {
+		return err
+	}
+
+	// Build list of snapshot metadata with associated replica.
+	var infos []replicaSnapshotInfo
+	for _, r := range replicas {
+		a, err := r.Snapshots(ctx)
 		if err != nil {
-			return err
+			log.Printf("cannot determine snapshots: %s", err)
+			ret = errExit // signal error return without printing message
+			continue
 		}
-
-		// Lookup database from configuration file by path.
-		if path, err := expand(fs.Arg(0)); err != nil {
-			return err
-		} else if dbc := config.DBConfig(path); dbc == nil {
-			return fmt.Errorf("database not found in config: %s", path)
-		} else if db, err = NewDBFromConfig(dbc); err != nil {
-			return err
-		}
-
-		// Filter by replica, if specified.
-		if *replicaName != "" {
-			if r = db.Replica(*replicaName); r == nil {
-				return fmt.Errorf("replica %q not found for database %q", *replicaName, db.Path())
-			}
+		for i := range a {
+			infos = append(infos, replicaSnapshotInfo{SnapshotInfo: a[i], replicaName: r.Name()})
 		}
 	}
 
-	// Find snapshots by db or replica.
-	var replicas []*litestream.Replica
-	if r != nil {
-		replicas = []*litestream.Replica{r}
-	} else {
-		replicas = db.Replicas
-	}
+	// Sort snapshots by creation time from newest to oldest.
+	sort.Slice(infos, func(i, j int) bool { return infos[i].CreatedAt.After(infos[j].CreatedAt) })
 
 	// List all snapshots.
-	w := tabwriter.NewWriter(os.Stdout, 0, 8, 2, ' ', 0)
+	w := tabwriter.NewWriter(c.stdout, 0, 8, 2, ' ', 0)
 	defer w.Flush()
 
 	fmt.Fprintln(w, "replica\tgeneration\tindex\tsize\tcreated")
-	for _, r := range replicas {
-		infos, err := r.Snapshots(ctx)
-		if err != nil {
-			log.Printf("cannot determine snapshots: %s", err)
-			continue
-		}
-		// Sort snapshots by creation time from newest to oldest.
-		sort.Slice(infos, func(i, j int) bool { return infos[i].CreatedAt.After(infos[j].CreatedAt) })
-		for _, info := range infos {
-			fmt.Fprintf(w, "%s\t%s\t%d\t%d\t%s\n",
-				r.Name(),
-				info.Generation,
-				info.Index,
-				info.Size,
-				info.CreatedAt.Format(time.RFC3339),
-			)
-		}
+	for _, info := range infos {
+		fmt.Fprintf(w, "%s\t%s\t%08x\t%d\t%s\n",
+			info.replicaName,
+			info.Generation,
+			info.Index,
+			info.Size,
+			info.CreatedAt.Format(time.RFC3339),
+		)
 	}
 
-	return nil
+	return ret
 }
 
 // Usage prints the help screen to STDOUT.
 func (c *SnapshotsCommand) Usage() {
-	fmt.Printf(`
+	fmt.Fprintf(c.stdout, `
 The snapshots command lists all snapshots available for a database or replica.
 
 Usage:
@@ -143,3 +133,9 @@ Examples:
 		DefaultConfigPath(),
 	)
 }
+
+// replicaSnapshotInfo represents snapshot metadata with associated replica name.
+type replicaSnapshotInfo struct {
+	litestream.SnapshotInfo
+	replicaName string
+}

cmd/litestream/snapshots_test.go

@@ -0,0 +1,128 @@
+package main_test
+
+import (
+	"context"
+	"flag"
+	"path/filepath"
+	"strings"
+	"testing"
+
+	"github.com/benbjohnson/litestream/internal/testingutil"
+)
+
+func TestSnapshotsCommand(t *testing.T) {
+	t.Run("OK", func(t *testing.T) {
+		testDir := filepath.Join("testdata", "snapshots", "ok")
+		defer testingutil.Setenv(t, "LITESTREAM_TESTDIR", testDir)()
+
+		m, _, stdout, _ := newMain()
+		if err := m.Run(context.Background(), []string{"snapshots", "-config", filepath.Join(testDir, "litestream.yml"), filepath.Join(testDir, "db")}); err != nil {
+			t.Fatal(err)
+		} else if got, want := stdout.String(), string(testingutil.MustReadFile(t, filepath.Join(testDir, "stdout"))); got != want {
+			t.Fatalf("stdout=%q, want %q", got, want)
+		}
+	})
+
+	t.Run("ReplicaName", func(t *testing.T) {
+		testDir := filepath.Join("testdata", "snapshots", "replica-name")
+		defer testingutil.Setenv(t, "LITESTREAM_TESTDIR", testDir)()
+
+		m, _, stdout, _ := newMain()
+		if err := m.Run(context.Background(), []string{"snapshots", "-config", filepath.Join(testDir, "litestream.yml"), "-replica", "replica1", filepath.Join(testDir, "db")}); err != nil {
+			t.Fatal(err)
+		} else if got, want := stdout.String(), string(testingutil.MustReadFile(t, filepath.Join(testDir, "stdout"))); got != want {
+			t.Fatalf("stdout=%q, want %q", got, want)
+		}
+	})
+
+	t.Run("ReplicaURL", func(t *testing.T) {
+		testDir := filepath.Join(testingutil.Getwd(t), "testdata", "snapshots", "replica-url")
+		defer testingutil.Setenv(t, "LITESTREAM_TESTDIR", testDir)()
+		replicaURL := "file://" + filepath.ToSlash(testDir) + "/replica"
+
+		m, _, stdout, _ := newMain()
+		if err := m.Run(context.Background(), []string{"snapshots", replicaURL}); err != nil {
+			t.Fatal(err)
+		} else if got, want := stdout.String(), string(testingutil.MustReadFile(t, filepath.Join(testDir, "stdout"))); got != want {
+			t.Fatalf("stdout=%q, want %q", got, want)
+		}
+	})
+
+	t.Run("ErrDatabaseOrReplicaRequired", func(t *testing.T) {
+		m, _, _, _ := newMain()
+		err := m.Run(context.Background(), []string{"snapshots"})
+		if err == nil || err.Error() != `database path or replica URL required` {
+			t.Fatalf("unexpected error: %s", err)
+		}
+	})
+
+	t.Run("ErrTooManyArguments", func(t *testing.T) {
+		m, _, _, _ := newMain()
+		err := m.Run(context.Background(), []string{"snapshots", "abc", "123"})
+		if err == nil || err.Error() != `too many arguments` {
+			t.Fatalf("unexpected error: %s", err)
+		}
+	})
+
+	t.Run("ErrInvalidFlags", func(t *testing.T) {
+		m, _, _, _ := newMain()
+		err := m.Run(context.Background(), []string{"snapshots", "-no-such-flag"})
+		if err == nil || err.Error() != `flag provided but not defined: -no-such-flag` {
+			t.Fatalf("unexpected error: %s", err)
+		}
+	})
+
+	t.Run("ErrConfigFileNotFound", func(t *testing.T) {
+		m, _, _, _ := newMain()
+		err := m.Run(context.Background(), []string{"snapshots", "-config", "/no/such/file", "/var/lib/db"})
+		if err == nil || err.Error() != `config file not found: /no/such/file` {
+			t.Fatalf("unexpected error: %s", err)
+		}
+	})
+
+	t.Run("ErrInvalidConfig", func(t *testing.T) {
+		testDir := filepath.Join("testdata", "snapshots", "invalid-config")
+		m, _, _, _ := newMain()
+		err := m.Run(context.Background(), []string{"snapshots", "-config", filepath.Join(testDir, "litestream.yml"), "/var/lib/db"})
+		if err == nil || !strings.Contains(err.Error(), `replica path cannot be a url`) {
+			t.Fatalf("unexpected error: %s", err)
+		}
+	})
+
+	t.Run("ErrDatabaseNotFound", func(t *testing.T) {
+		testDir := filepath.Join("testdata", "snapshots", "database-not-found")
+		defer testingutil.Setenv(t, "LITESTREAM_TESTDIR", testDir)()
+
+		m, _, _, _ := newMain()
+		err := m.Run(context.Background(), []string{"snapshots", "-config", filepath.Join(testDir, "litestream.yml"), "/no/such/db"})
+		if err == nil || err.Error() != `database not found in config: /no/such/db` {
+			t.Fatalf("unexpected error: %s", err)
+		}
+	})
+
+	t.Run("ErrReplicaNotFound", func(t *testing.T) {
+		testDir := filepath.Join(testingutil.Getwd(t), "testdata", "snapshots", "replica-not-found")
+		defer testingutil.Setenv(t, "LITESTREAM_TESTDIR", testDir)()
+
+		m, _, _, _ := newMain()
+		err := m.Run(context.Background(), []string{"snapshots", "-config", filepath.Join(testDir, "litestream.yml"), "-replica", "no_such_replica", filepath.Join(testDir, "db")})
+		if err == nil || err.Error() != `replica "no_such_replica" not found for database "`+filepath.Join(testDir, "db")+`"` {
+			t.Fatalf("unexpected error: %s", err)
+		}
+	})
+
+	t.Run("ErrInvalidReplicaURL", func(t *testing.T) {
+		m, _, _, _ := newMain()
+		err := m.Run(context.Background(), []string{"snapshots", "xyz://xyz"})
+		if err == nil || !strings.Contains(err.Error(), `unknown replica type in config: "xyz"`) {
+			t.Fatalf("unexpected error: %s", err)
+		}
+	})
+
+	t.Run("Usage", func(t *testing.T) {
+		m, _, _, _ := newMain()
+		if err := m.Run(context.Background(), []string{"snapshots", "-h"}); err != flag.ErrHelp {
+			t.Fatalf("unexpected error: %s", err)
+		}
+	})
+}

cmd/litestream/testdata/Makefile

@@ -0,0 +1,13 @@
+.PHONY: default
+default:
+	make -C generations/ok
+	make -C generations/no-database
+	make -C generations/replica-name
+	make -C generations/replica-url
+	make -C restore/latest-replica
+	make -C snapshots/ok
+	make -C snapshots/replica-name
+	make -C snapshots/replica-url
+	make -C wal/ok
+	make -C wal/replica-name
+	make -C wal/replica-url

cmd/litestream/testdata/databases/invalid-config/litestream.yml

@@ -0,0 +1,4 @@
+dbs:
+  - path: /var/lib/db
+    replicas:
+      - path: s3://bkt/db

cmd/litestream/testdata/databases/no-databases/litestream.yml

@@ -0,0 +1 @@
+dbs:

cmd/litestream/testdata/databases/no-databases/stdout

@@ -0,0 +1 @@
+No databases found in config file.

cmd/litestream/testdata/databases/ok/litestream.yml

@@ -0,0 +1,7 @@
+dbs:
+  - path: /var/lib/db
+    replicas:
+      - path: /var/lib/replica
+      - url:  s3://mybkt/db
+
+  - path: /my/other/db

cmd/litestream/testdata/databases/ok/stdout

@@ -0,0 +1,3 @@
+path          replicas
+/var/lib/db   file,s3
+/my/other/db  

cmd/litestream/testdata/generations/database-not-found/litestream.yml

@@ -0,0 +1,2 @@
+dbs:
+  - path: $LITESTREAM_TESTDIR/db

cmd/litestream/testdata/generations/invalid-config/litestream.yml

@@ -0,0 +1,4 @@
+dbs:
+  - path: /var/lib/db
+    replicas:
+      - path: s3://bkt/db

cmd/litestream/testdata/generations/no-database/Makefile

@@ -0,0 +1,4 @@
+.PHONY: default
+default:
+	TZ=UTC touch -ct 200001010000 replica/generations/0000000000000000/snapshots/00000000.snapshot.lz4
+	TZ=UTC touch -ct 200001020000 replica/generations/0000000000000001/snapshots/00000000.snapshot.lz4

cmd/litestream/testdata/generations/no-database/litestream.yml

@@ -0,0 +1,4 @@
+dbs:
+  - path: $LITESTREAM_TESTDIR/db
+    replicas:
+      - path: $LITESTREAM_TESTDIR/replica

cmd/litestream/testdata/generations/no-database/stdout

@@ -0,0 +1,3 @@
+name  generation        lag  start                 end
+file  0000000000000000  -    2000-01-01T00:00:00Z  2000-01-01T00:00:00Z
+file  0000000000000001  -    2000-01-02T00:00:00Z  2000-01-02T00:00:00Z

cmd/litestream/testdata/generations/ok/Makefile

@@ -0,0 +1,9 @@
+.PHONY: default
+default:
+	TZ=UTC touch -ct 200001030000 db
+	TZ=UTC touch -ct 200001010000 replica/generations/0000000000000000/snapshots/00000000.snapshot.lz4
+	TZ=UTC touch -ct 200001020000 replica/generations/0000000000000000/snapshots/00000001.snapshot.lz4
+	TZ=UTC touch -ct 200001010000 replica/generations/0000000000000000/wal/00000000/00000000.wal.lz4
+	TZ=UTC touch -ct 200001020000 replica/generations/0000000000000000/wal/00000000/00000001.wal.lz4
+	TZ=UTC touch -ct 200001030000 replica/generations/0000000000000000/wal/00000001/00000000.wal.lz4
+	TZ=UTC touch -ct 200001010000 replica/generations/0000000000000001/snapshots/00000000.snapshot.lz4

cmd/litestream/testdata/generations/ok/litestream.yml

@@ -0,0 +1,4 @@
+dbs:
+  - path: $LITESTREAM_TESTDIR/db
+    replicas:
+      - path: $LITESTREAM_TESTDIR/replica

cmd/litestream/testdata/generations/ok/stdout

@@ -0,0 +1,3 @@
+name  generation        lag      start                 end
+file  0000000000000000  0s       2000-01-01T00:00:00Z  2000-01-03T00:00:00Z
+file  0000000000000001  48h0m0s  2000-01-01T00:00:00Z  2000-01-01T00:00:00Z

cmd/litestream/testdata/generations/replica-name/Makefile

@@ -0,0 +1,5 @@
+.PHONY: default
+default:
+	TZ=UTC touch -ct 200001030000 db
+	TZ=UTC touch -ct 200001010000 replica0/generations/0000000000000000/snapshots/00000000.snapshot.lz4
+	TZ=UTC touch -ct 200001020000 replica1/generations/0000000000000001/snapshots/00000000.snapshot.lz4

cmd/litestream/testdata/generations/replica-name/litestream.yml

@@ -0,0 +1,7 @@
+dbs:
+  - path: $LITESTREAM_TESTDIR/db
+    replicas:
+      - name: replica0
+        path: $LITESTREAM_TESTDIR/replica0
+      - name: replica1
+        path: $LITESTREAM_TESTDIR/replica1

cmd/litestream/testdata/generations/replica-name/stdout

@@ -0,0 +1,2 @@
+name      generation        lag      start                 end
+replica1  0000000000000001  24h0m0s  2000-01-02T00:00:00Z  2000-01-02T00:00:00Z

cmd/litestream/testdata/generations/replica-not-found/litestream.yml

@@ -0,0 +1,4 @@
+dbs:
+  - path: $LITESTREAM_TESTDIR/db
+    replicas:
+      - url: s3://bkt/db

cmd/litestream/testdata/generations/replica-url/Makefile

@@ -0,0 +1,9 @@
+.PHONY: default
+default:
+	TZ=UTC touch -ct 200001010000 replica/generations/0000000000000000/snapshots/00000000.snapshot.lz4
+	TZ=UTC touch -ct 200001020000 replica/generations/0000000000000000/snapshots/00000001.snapshot.lz4
+	TZ=UTC touch -ct 200001010000 replica/generations/0000000000000000/wal/00000000/00000000.wal.lz4
+	TZ=UTC touch -ct 200001020000 replica/generations/0000000000000000/wal/00000000/00000001.wal.lz4
+	TZ=UTC touch -ct 200001030000 replica/generations/0000000000000000/wal/00000001/00000000.wal.lz4
+	TZ=UTC touch -ct 200001020000 replica/generations/0000000000000001/snapshots/00000000.snapshot.lz4
+

cmd/litestream/testdata/generations/replica-url/litestream.yml

@@ -0,0 +1,4 @@
+dbs:
+  - path: $LITESTREAM_TESTDIR/db
+    replicas:
+      - path: $LITESTREAM_TESTDIR/replica

cmd/litestream/testdata/generations/replica-url/stdout

@@ -0,0 +1,3 @@
+name  generation        lag  start                 end
+file  0000000000000000  -    2000-01-01T00:00:00Z  2000-01-03T00:00:00Z
+file  0000000000000001  -    2000-01-02T00:00:00Z  2000-01-02T00:00:00Z

cmd/litestream/testdata/restore/database-not-found/litestream.yml

@@ -0,0 +1,4 @@
+dbs:
+  - path: $LITESTREAM_TESTDIR/db
+    replicas:
+      - path: $LITESTREAM_TESTDIR/replica

cmd/litestream/testdata/restore/generation-with-no-replica/litestream.yml

@@ -0,0 +1,5 @@
+dbs:
+  - path: $LITESTREAM_TESTDIR/db
+    replicas:
+      - path: $LITESTREAM_TESTDIR/replica0
+      - path: $LITESTREAM_TESTDIR/replica1

cmd/litestream/testdata/restore/if-db-not-exists-flag/litestream.yml

@@ -0,0 +1,4 @@
+dbs:
+  - path: $LITESTREAM_TESTDIR/db
+    replicas:
+      - path: $LITESTREAM_TESTDIR/replica

cmd/litestream/testdata/restore/if-db-not-exists-flag/stdout

@@ -0,0 +1 @@
+database already exists, skipping

cmd/litestream/testdata/restore/if-replica-exists-flag/litestream.yml

@@ -0,0 +1,4 @@
+dbs:
+  - path: $LITESTREAM_TESTDIR/db
+    replicas:
+      - path: $LITESTREAM_TESTDIR/replica

cmd/litestream/testdata/restore/if-replica-exists-flag/stdout

@@ -0,0 +1 @@
+no matching backups found, skipping

cmd/litestream/testdata/restore/invalid-config/litestream.yml

@@ -0,0 +1,4 @@
+dbs:
+  - path: /var/lib/db
+    replicas:
+      - path: s3://bkt/db

cmd/litestream/testdata/restore/latest-replica/Makefile

@@ -0,0 +1,6 @@
+.PHONY: default
+default:
+	TZ=UTC touch -ct 200001010000 replica0/generations/0000000000000000/snapshots/00000000.snapshot.lz4
+	TZ=UTC touch -ct 200001020000 replica1/generations/0000000000000002/snapshots/00000000.snapshot.lz4
+	TZ=UTC touch -ct 200001030000 replica0/generations/0000000000000001/snapshots/00000000.snapshot.lz4
+

cmd/litestream/testdata/restore/latest-replica/litestream.yml

@@ -0,0 +1,7 @@
+dbs:
+  - path: $LITESTREAM_TESTDIR/db
+    replicas:
+      - name: replica0
+        path: $LITESTREAM_TESTDIR/replica0
+      - name: replica1
+        path: $LITESTREAM_TESTDIR/replica1

cmd/litestream/testdata/restore/no-backups/litestream.yml

@@ -0,0 +1,4 @@
+dbs:
+  - path: $LITESTREAM_TESTDIR/db
+    replicas:
+      - path: $LITESTREAM_TESTDIR/replica

cmd/litestream/testdata/restore/no-generation/litestream.yml

@@ -0,0 +1,4 @@
+dbs:
+  - path: $LITESTREAM_TESTDIR/db
+    replicas:
+      - path: $LITESTREAM_TESTDIR/replica

cmd/litestream/testdata/restore/no-replicas/litestream.yml

@@ -0,0 +1,2 @@
+dbs:
+  - path: $LITESTREAM_TESTDIR/db

cmd/litestream/testdata/restore/no-snapshots/litestream.yml

@@ -0,0 +1,4 @@
+dbs:
+  - path: $LITESTREAM_TESTDIR/db
+    replicas:
+      - path: $LITESTREAM_TESTDIR/replica

cmd/litestream/testdata/restore/ok/README

@@ -0,0 +1,36 @@
+To reproduce this testdata, run sqlite3 and execute:
+
+	PRAGMA journal_mode = WAL;
+	CREATE TABLE t (x);
+	INSERT INTO t (x) VALUES (1);
+	INSERT INTO t (x) VALUES (2);
+
+	sl3 split -o generations/0000000000000000/wal/00000000 db-wal
+	cp db generations/0000000000000000/snapshots/00000000.snapshot
+	lz4 -c --rm generations/0000000000000000/snapshots/00000000.snapshot
+
+
+Then execute:
+
+	PRAGMA wal_checkpoint(TRUNCATE);
+	INSERT INTO t (x) VALUES (3);
+
+	sl3 split -o generations/0000000000000000/wal/00000001 db-wal
+
+
+Then execute:
+
+	PRAGMA wal_checkpoint(TRUNCATE);
+	INSERT INTO t (x) VALUES (4);
+	INSERT INTO t (x) VALUES (5);
+
+	sl3 split -o generations/0000000000000000/wal/00000002 db-wal
+
+
+Finally, obtain the final snapshot:
+
+	PRAGMA wal_checkpoint(TRUNCATE);
+
+	cp db 00000002.db
+	rm db*
+

cmd/litestream/testdata/restore/ok/litestream.yml

@@ -0,0 +1,4 @@
+dbs:
+  - path: $LITESTREAM_TESTDIR/db
+    replicas:
+      - path: $LITESTREAM_TESTDIR/replica

cmd/litestream/testdata/restore/output-path-exists/litestream.yml

@@ -0,0 +1,4 @@
+dbs:
+  - path: $LITESTREAM_TESTDIR/db
+    replicas:
+      - path: $LITESTREAM_TESTDIR/replica

cmd/litestream/testdata/restore/replica-name/litestream.yml

@@ -0,0 +1,7 @@
+dbs:
+  - path: $LITESTREAM_TESTDIR/db
+    replicas:
+      - name: replica0
+        path: $LITESTREAM_TESTDIR/replica0
+      - name: replica1
+        path: $LITESTREAM_TESTDIR/replica1

cmd/litestream/testdata/restore/replica-not-found/litestream.yml

@@ -0,0 +1,5 @@
+dbs:
+  - path: $LITESTREAM_TESTDIR/db
+    replicas:
+      - name: replica0
+        path: $LITESTREAM_TESTDIR/replica

cmd/litestream/testdata/snapshots/database-not-found/litestream.yml

@@ -0,0 +1,2 @@
+dbs:
+  - path: $LITESTREAM_TESTDIR/db

cmd/litestream/testdata/snapshots/invalid-config/litestream.yml

@@ -0,0 +1,4 @@
+dbs:
+  - path: /var/lib/db
+    replicas:
+      - path: s3://bkt/db

cmd/litestream/testdata/snapshots/ok/Makefile

@@ -0,0 +1,6 @@
+.PHONY: default
+default:
+	TZ=UTC touch -ct 200001010000 replica/generations/0000000000000000/snapshots/00000000.snapshot.lz4
+	TZ=UTC touch -ct 200001020000 replica/generations/0000000000000000/snapshots/00000001.snapshot.lz4
+	TZ=UTC touch -ct 200001030000 replica/generations/0000000000000001/snapshots/00000000.snapshot.lz4
+