use a pkg var for ErrNoValidBackends

Signed-off-by: James Ranson <[email protected]>

pkg/config/errors.go

@@ -0,0 +1,5 @@
+package config
+
+import "errors"
+
+var ErrNoValidBackends = errors.New("no valid backends configured")

pkg/config/loader.go

@@ -17,7 +17,6 @@
 package config
 
 import (
-	"errors"
 	"net/url"
 	"time"
 
@@ -72,7 +71,7 @@ func Load(applicationName string, applicationVersion string, arguments []string)
 	}
 
 	if len(c.Backends) == 0 {
-		return nil, flags, errors.New("no valid backends configured")
+		return nil, flags, ErrNoValidBackends
 	}
 
 	ncl, err := negative.ConfigLookup(c.NegativeCacheConfigs).Validate()

pkg/config/loader_test.go

@@ -620,7 +620,7 @@ func TestLoadConfigurationWarning2(t *testing.T) {
 func TestLoadEmptyArgs(t *testing.T) {
 	a := []string{}
 	_, _, err := Load("trickster-test", "0", a)
-	if err == nil {
-		t.Error("expected error: no valid backends configured")
+	if err != ErrNoValidBackends {
+		t.Error("expected error:", ErrNoValidBackends)
 	}
 }