First crack at backoff function

client/backoff_test.go

@@ -0,0 +1,26 @@
+package client
+
+import (
+	"math"
+	"testing"
+	"time"
+
+	"golang.org/x/net/context"
+)
+
+func TestBackoff(t *testing.T) {
+	delta := time.Duration(0)
+
+	for i := 0; i < 5; i++ {
+		d, err := exponentialBackoff(context.TODO(), NewJsonRequest("test", "test", nil), i)
+		if err != nil {
+			t.Fatal(err)
+		}
+
+		if d < delta {
+			t.Fatalf("Expected greater than %v, got %v", delta, d)
+		}
+
+		delta = time.Millisecond * time.Duration(math.Pow(10, float64(i+1)))
+	}
+}