feat(OneDrive): support Retry-After throttling control from Graph API (#280)

pkg/filesystem/chunk/backoff/backoff_test.go

@@ -1,7 +1,9 @@
 package backoff
 
 import (
+	"errors"
 	"github.com/stretchr/testify/assert"
+	"net/http"
 	"testing"
 	"time"
 )
@@ -9,14 +11,51 @@ import (
 func TestConstantBackoff_Next(t *testing.T) {
 	a := assert.New(t)
 
-	b := &ConstantBackoff{Sleep: time.Duration(0), Max: 3}
-	a.True(b.Next())
-	a.True(b.Next())
-	a.True(b.Next())
-	a.False(b.Next())
-	b.Reset()
-	a.True(b.Next())
-	a.True(b.Next())
-	a.True(b.Next())
-	a.False(b.Next())
+	// General error
+	{
+		err := errors.New("error")
+		b := &ConstantBackoff{Sleep: time.Duration(0), Max: 3}
+		a.True(b.Next(err))
+		a.True(b.Next(err))
+		a.True(b.Next(err))
+		a.False(b.Next(err))
+		b.Reset()
+		a.True(b.Next(err))
+		a.True(b.Next(err))
+		a.True(b.Next(err))
+		a.False(b.Next(err))
+	}
+
+	// Retryable error
+	{
+		err := &RetryableError{RetryAfter: time.Duration(1)}
+		b := &ConstantBackoff{Sleep: time.Duration(0), Max: 3}
+		a.True(b.Next(err))
+		a.True(b.Next(err))
+		a.True(b.Next(err))
+		a.False(b.Next(err))
+		b.Reset()
+		a.True(b.Next(err))
+		a.True(b.Next(err))
+		a.True(b.Next(err))
+		a.False(b.Next(err))
+	}
+
+}
+
+func TestNewRetryableErrorFromHeader(t *testing.T) {
+	a := assert.New(t)
+	// no retry-after header
+	{
+		err := NewRetryableErrorFromHeader(nil, http.Header{})
+		a.Empty(err.RetryAfter)
+	}
+
+	// with retry-after header
+	{
+		header := http.Header{}
+		header.Add("retry-after", "120")
+		err := NewRetryableErrorFromHeader(nil, header)
+		a.EqualValues(time.Duration(120)*time.Second, err.RetryAfter)
+	}
 }