diff --git a/Makefile b/Makefile
index afbfe31ab..715bf6344 100644
--- a/Makefile
+++ b/Makefile
@@ -61,3 +61,6 @@ tag:
 
 retag:
 	git tag -f $(LAST_TAG)
+
+gen_tests:
+	cd fstest/fstests && go run gen_tests.go
diff --git a/drive/drive_test.go b/drive/drive_test.go
index 803c6cf4c..d8ee07f3b 100644
--- a/drive/drive_test.go
+++ b/drive/drive_test.go
@@ -1,4 +1,7 @@
 // Test Drive filesystem interface
+//
+// Automatically generated - DO NOT EDIT
+// Regenerate with: go run gen_tests.go or make gen_tests
 package drive_test
 
 import (
diff --git a/dropbox/dropbox_test.go b/dropbox/dropbox_test.go
index 9ba2d08d7..99e816cfc 100644
--- a/dropbox/dropbox_test.go
+++ b/dropbox/dropbox_test.go
@@ -1,4 +1,7 @@
 // Test Dropbox filesystem interface
+//
+// Automatically generated - DO NOT EDIT
+// Regenerate with: go run gen_tests.go or make gen_tests
 package dropbox_test
 
 import (
diff --git a/fstest/fstest.go b/fstest/fstest.go
index 7ffbcb4fd..e103b7648 100644
--- a/fstest/fstest.go
+++ b/fstest/fstest.go
@@ -17,6 +17,12 @@ import (
 
 var Fatalf = log.Fatalf
 
+// Seed the random number generator
+func init() {
+	rand.Seed(time.Now().UnixNano())
+
+}
+
 // Represents an item for checking
 type Item struct {
 	Path    string
@@ -25,6 +31,15 @@ type Item struct {
 	Size    int64
 }
 
+// check the mod time to the given precision
+func (i *Item) CheckModTime(obj fs.Object, modTime time.Time) {
+	dt := modTime.Sub(i.ModTime)
+	precision := obj.Fs().Precision()
+	if dt >= precision || dt <= -precision {
+		Fatalf("%s: Modification time difference too big |%s| > %s (%s vs %s)", obj.Remote(), dt, precision, modTime, i.ModTime)
+	}
+}
+
 func (i *Item) Check(obj fs.Object) {
 	if obj == nil {
 		Fatalf("Object is nil")
@@ -40,13 +55,7 @@ func (i *Item) Check(obj fs.Object) {
 	if i.Size != obj.Size() {
 		Fatalf("%s: Size incorrect - expecting %d got %d", obj.Remote(), i.Size, obj.Size())
 	}
-	// check the mod time to the given precision
-	modTime := obj.ModTime()
-	dt := modTime.Sub(i.ModTime)
-	if dt >= fs.Config.ModifyWindow || dt <= -fs.Config.ModifyWindow {
-		Fatalf("%s: Modification time difference too big |%s| > %s (%s vs %s)", obj.Remote(), dt, fs.Config.ModifyWindow, modTime, i.ModTime)
-	}
-
+	i.CheckModTime(obj, obj.ModTime())
 }
 
 // Represents all items for checking
diff --git a/fstest/fstests/fstests.go b/fstest/fstests/fstests.go
index ad7ba2282..99be49c6f 100644
--- a/fstest/fstests/fstests.go
+++ b/fstest/fstests/fstests.go
@@ -110,7 +110,7 @@ func TestFsNewFsObjectNotFound(t *testing.T) {
 func findObject(t *testing.T, Name string) fs.Object {
 	obj := remote.NewFsObject(Name)
 	if obj == nil {
-		t.Fatalf("nil object")
+		t.Fatalf("Object not found: %q", Name)
 	}
 	return obj
 }
@@ -235,9 +235,7 @@ func TestObjectMd5sum(t *testing.T) {
 func TestObjectModTime(t *testing.T) {
 	skipIfNotOk(t)
 	obj := findObject(t, file1.Path)
-	if !obj.ModTime().Equal(file1.ModTime) {
-		t.Errorf("ModTime is wrong %v != %v", obj.ModTime(), file1.ModTime)
-	}
+	file1.CheckModTime(obj, obj.ModTime())
 }
 
 func TestObjectSetModTime(t *testing.T) {
@@ -245,11 +243,8 @@ func TestObjectSetModTime(t *testing.T) {
 	newModTime := fstest.Time("2011-12-13T14:15:16.999999999Z")
 	obj := findObject(t, file1.Path)
 	obj.SetModTime(newModTime)
-	// Check in this object
-	if !obj.ModTime().Equal(newModTime) {
-		t.Errorf("newModTime is wrong %v != %v", obj.ModTime(), newModTime)
-	}
 	file1.ModTime = newModTime
+	file1.CheckModTime(obj, newModTime)
 	// And make a new object and read it from there too
 	TestObjectModTime(t)
 }
diff --git a/fstest/fstests/gen_tests.go b/fstest/fstests/gen_tests.go
new file mode 100644
index 000000000..9c8e5a7f3
--- /dev/null
+++ b/fstest/fstests/gen_tests.go
@@ -0,0 +1,143 @@
+// +build ignore
+
+// Make the test files from fstests.go
+package main
+
+import (
+	"bufio"
+	"html/template"
+	"log"
+	"os"
+	"os/exec"
+	"regexp"
+	"strings"
+)
+
+// Search fstests.go and return all the test function names
+func findTestFunctions() []string {
+	fns := []string{}
+	matcher := regexp.MustCompile(`^func\s+(Test.*?)\(`)
+
+	in, err := os.Open("fstests.go")
+	if err != nil {
+		log.Fatalf("Couldn't open fstests.go: %v", err)
+	}
+	defer in.Close()
+
+	scanner := bufio.NewScanner(in)
+	for scanner.Scan() {
+		line := scanner.Text()
+		matches := matcher.FindStringSubmatch(line)
+		if len(matches) > 0 {
+			fns = append(fns, matches[1])
+		}
+	}
+
+	if err := scanner.Err(); err != nil {
+		log.Fatalf("Error scanning file: %v", err)
+	}
+	return fns
+}
+
+// Data to substitute
+type Data struct {
+	Regenerate  string
+	FsName      string
+	UpperFsName string
+	TestName    string
+	ObjectName  string
+	Fns         []string
+}
+
+var testProgram = `
+// Test {{ .UpperFsName }} filesystem interface
+//
+// Automatically generated - DO NOT EDIT
+// Regenerate with: {{ .Regenerate }}
+package {{ .FsName }}_test
+
+import (
+	"testing"
+
+	"github.com/ncw/rclone/fs"
+	"github.com/ncw/rclone/fstest/fstests"
+	"github.com/ncw/rclone/{{ .FsName }}"
+)
+
+func init() {
+	fstests.NilObject = fs.Object((*{{ .FsName }}.FsObject{{ .ObjectName }})(nil))
+	fstests.RemoteName = "{{ .TestName }}"
+}
+
+// Generic tests for the Fs
+{{ range $fn := .Fns }}func {{ $fn }}(t *testing.T){ fstests.{{ $fn }}(t) }
+{{ end }}
+`
+
+// Generate test file piping it through gofmt
+func generateTestProgram(t *template.Template, fns []string, Fsname string) {
+	fsname := strings.ToLower(Fsname)
+	TestName := "Test" + Fsname + ":"
+	outfile := "../../" + fsname + "/" + fsname + "_test.go"
+	// Find last capitalised group to be object name
+	matcher := regexp.MustCompile(`([A-Z][a-z0-9]+)$`)
+	matches := matcher.FindStringSubmatch(Fsname)
+	if len(matches) == 0 {
+		log.Fatalf("Couldn't find object name in %q", Fsname)
+	}
+	ObjectName := matches[1]
+
+	if fsname == "local" {
+		TestName = ""
+	}
+
+	data := Data{
+		Regenerate:  "go run gen_tests.go or make gen_tests",
+		FsName:      fsname,
+		UpperFsName: Fsname,
+		TestName:    TestName,
+		ObjectName:  ObjectName,
+		Fns:         fns,
+	}
+
+	cmd := exec.Command("gofmt")
+
+	log.Printf("Writing %q", outfile)
+	out, err := os.Create(outfile)
+	if err != nil {
+		log.Fatal(err)
+	}
+	cmd.Stdout = out
+
+	gofmt, err := cmd.StdinPipe()
+	if err != nil {
+		log.Fatal(err)
+	}
+	if err = cmd.Start(); err != nil {
+		log.Fatal(err)
+	}
+	if err = t.Execute(gofmt, data); err != nil {
+		log.Fatal(err)
+	}
+	if err = gofmt.Close(); err != nil {
+		log.Fatal(err)
+	}
+	if err = cmd.Wait(); err != nil {
+		log.Fatal(err)
+	}
+	if err = out.Close(); err != nil {
+		log.Fatal(err)
+	}
+}
+
+func main() {
+	fns := findTestFunctions()
+	t := template.Must(template.New("main").Parse(testProgram))
+	generateTestProgram(t, fns, "Local")
+	generateTestProgram(t, fns, "Swift")
+	generateTestProgram(t, fns, "S3")
+	generateTestProgram(t, fns, "Drive")
+	generateTestProgram(t, fns, "GoogleCloudStorage")
+	generateTestProgram(t, fns, "Dropbox")
+	log.Printf("Done")
+}
diff --git a/googlecloudstorage/googlecloudstorage_test.go b/googlecloudstorage/googlecloudstorage_test.go
index b83a0b36e..31487840a 100644
--- a/googlecloudstorage/googlecloudstorage_test.go
+++ b/googlecloudstorage/googlecloudstorage_test.go
@@ -1,4 +1,7 @@
-// Test Google cloud storage filesystem interface
+// Test GoogleCloudStorage filesystem interface
+//
+// Automatically generated - DO NOT EDIT
+// Regenerate with: go run gen_tests.go or make gen_tests
 package googlecloudstorage_test
 
 import (
diff --git a/local/local_test.go b/local/local_test.go
index 689be7fff..8f67161e5 100644
--- a/local/local_test.go
+++ b/local/local_test.go
@@ -1,4 +1,7 @@
 // Test Local filesystem interface
+//
+// Automatically generated - DO NOT EDIT
+// Regenerate with: go run gen_tests.go or make gen_tests
 package local_test
 
 import (
diff --git a/rclonetest/rclonetest.go b/rclonetest/rclonetest.go
index 6c2827069..2a94f3eea 100644
--- a/rclonetest/rclonetest.go
+++ b/rclonetest/rclonetest.go
@@ -7,7 +7,6 @@ import (
 	"fmt"
 	"io/ioutil"
 	"log"
-	"math/rand"
 	"os"
 	"path"
 	"time"
@@ -251,7 +250,6 @@ func main() {
 		os.Exit(0)
 	}
 	fs.LoadConfig()
-	rand.Seed(time.Now().UnixNano())
 	args := pflag.Args()
 
 	if len(args) != 1 {
diff --git a/s3/s3_test.go b/s3/s3_test.go
index a2ef7054a..f63e794ff 100644
--- a/s3/s3_test.go
+++ b/s3/s3_test.go
@@ -1,4 +1,7 @@
 // Test S3 filesystem interface
+//
+// Automatically generated - DO NOT EDIT
+// Regenerate with: go run gen_tests.go or make gen_tests
 package s3_test
 
 import (
diff --git a/swift/swift_test.go b/swift/swift_test.go
index 19f47d7d9..d09f0bf46 100644
--- a/swift/swift_test.go
+++ b/swift/swift_test.go
@@ -1,4 +1,7 @@
 // Test Swift filesystem interface
+//
+// Automatically generated - DO NOT EDIT
+// Regenerate with: go run gen_tests.go or make gen_tests
 package swift_test
 
 import (