fstest: make ChangeNotify test clean up after itself and be more reliable

Previous to this fix old notifications could creep in and cause the
test to fail.  It also left files around which upset the TestObjectRemove test.

Fixes #2177

fstest/fstests/fstests.go

@@ -704,6 +704,11 @@ func TestFsChangeNotify(t *testing.T) {
 	dirChanges := []string{}
 	objChanges := []string{}
 	quitChannel := doChangeNotify(func(x string, e fs.EntryType) {
+		fs.Debugf(nil, "doChangeNotify(%q, %+v)", x, e)
+		if strings.HasPrefix(x, file1.Path[:5]) || strings.HasPrefix(x, file2.Path[:5]) {
+			fs.Debugf(nil, "Ignoring notify for file1 or file2: %q, %v", x, e)
+			return
+		}
 		if e == fs.EntryDirectory {
 			dirChanges = append(dirChanges, x)
 		} else if e == fs.EntryObject {
@@ -712,24 +717,38 @@ func TestFsChangeNotify(t *testing.T) {
 	}, time.Second)
 	defer func() { close(quitChannel) }()
 
+	var dirs []string
 	for _, idx := range []int{1, 3, 2} {
-		err = operations.Mkdir(remote, fmt.Sprintf("dir/subdir%d", idx))
+		dir := fmt.Sprintf("dir/subdir%d", idx)
+		err = operations.Mkdir(remote, dir)
 		require.NoError(t, err)
+		dirs = append(dirs, dir)
 	}
 
 	contents := fstest.RandomString(100)
 	buf := bytes.NewBufferString(contents)
 
+	var objs []fs.Object
 	for _, idx := range []int{2, 4, 3} {
 		obji := object.NewStaticObjectInfo(fmt.Sprintf("dir/file%d", idx), time.Now(), int64(buf.Len()), true, nil, nil)
-		_, err = remote.Put(buf, obji)
+		o, err := remote.Put(buf, obji)
 		require.NoError(t, err)
+		objs = append(objs, o)
 	}
 
 	time.Sleep(3 * time.Second)
 
 	assert.Equal(t, []string{"dir/subdir1", "dir/subdir3", "dir/subdir2"}, dirChanges)
 	assert.Equal(t, []string{"dir/file2", "dir/file4", "dir/file3"}, objChanges)
+
+	// tidy up afterwards
+	for _, o := range objs {
+		assert.NoError(t, o.Remove())
+	}
+	dirs = append(dirs, "dir")
+	for _, dir := range dirs {
+		assert.NoError(t, remote.Rmdir(dir))
+	}
 }
 
 // TestObjectString tests the Object String method