Add test for to prevent double create

backend/local/backend_test.go

@@ -9,6 +9,7 @@ import (
 
 func TestLocalBackendCreate(t *testing.T)           { test.Create(t) }
 func TestLocalBackendOpen(t *testing.T)             { test.Open(t) }
+func TestLocalBackendCreateWithConfig(t *testing.T) { test.CreateWithConfig(t) }
 func TestLocalBackendLocation(t *testing.T)         { test.Location(t) }
 func TestLocalBackendConfig(t *testing.T)           { test.Config(t) }
 func TestLocalBackendGetReader(t *testing.T)        { test.GetReader(t) }

backend/local/local_test.go

@@ -1,7 +1,6 @@
 package local_test
 
 import (
-	"errors"
 	"fmt"
 	"io/ioutil"
 	"os"
@@ -15,28 +14,35 @@ var tempBackendDir string
 
 //go:generate go run ../test/generate_backend_tests.go
 
-func init() {
+func createTempdir() error {
-	test.CreateFn = func() (backend.Backend, error) {
 	if tempBackendDir != "" {
-			return nil, errors.New("temporary local backend dir already exists")
+		return nil
 	}
 
 	tempdir, err := ioutil.TempDir("", "restic-local-test-")
 	if err != nil {
-			return nil, err
+		return err
 	}
 
 	fmt.Printf("created new test backend at %v\n", tempdir)
 	tempBackendDir = tempdir
+	return nil
+}
 
-		return local.Create(tempdir)
+func init() {
+	test.CreateFn = func() (backend.Backend, error) {
+		err := createTempdir()
+		if err != nil {
+			return nil, err
+		}
+		return local.Create(tempBackendDir)
 	}
 
 	test.OpenFn = func() (backend.Backend, error) {
-		if tempBackendDir == "" {
+		err := createTempdir()
-			return nil, errors.New("repository not initialized")
+		if err != nil {
+			return nil, err
 		}
-
 		return local.Open(tempBackendDir)
 	}
 

backend/mem_backend_test.go

@@ -9,6 +9,7 @@ import (
 
 func TestMemBackendCreate(t *testing.T)           { test.Create(t) }
 func TestMemBackendOpen(t *testing.T)             { test.Open(t) }
+func TestMemBackendCreateWithConfig(t *testing.T) { test.CreateWithConfig(t) }
 func TestMemBackendLocation(t *testing.T)         { test.Location(t) }
 func TestMemBackendConfig(t *testing.T)           { test.Config(t) }
 func TestMemBackendGetReader(t *testing.T)        { test.GetReader(t) }

backend/test/backend_test.go

@@ -9,6 +9,7 @@ import (
 
 func TestTestBackendCreate(t *testing.T)           { test.Create(t) }
 func TestTestBackendOpen(t *testing.T)             { test.Open(t) }
+func TestTestBackendCreateWithConfig(t *testing.T) { test.CreateWithConfig(t) }
 func TestTestBackendLocation(t *testing.T)         { test.Location(t) }
 func TestTestBackendConfig(t *testing.T)           { test.Config(t) }
 func TestTestBackendGetReader(t *testing.T)        { test.GetReader(t) }

backend/test/tests.go

@@ -107,6 +107,32 @@ func Open(t testing.TB) {
 	}
 }
 
+// CreateWithConfig tests that creating a backend in a location which already
+// has a config file fails.
+func CreateWithConfig(t testing.TB) {
+	if CreateFn == nil {
+		t.Fatalf("CreateFn not set")
+	}
+
+	b := open(t)
+	defer close(t)
+
+	// save a config
+	store(t, b, backend.Config, []byte("test config"))
+
+	// now create the backend again, this must fail
+	_, err := CreateFn()
+	if err == nil {
+		t.Fatalf("expected error not found for creating a backend with an existing config file")
+	}
+
+	// remove config
+	err = b.Remove(backend.Config, "")
+	if err != nil {
+		t.Fatalf("unexpected error removing config: %v", err)
+	}
+}
+
 // Location tests that a location string is returned.
 func Location(t testing.TB) {
 	b := open(t)