removed test dependency on errors.Is

Author: savaki

errors/errors_test.go

@@ -1,38 +1,54 @@
 package errors
 
 import (
-	"errors"
 	"io"
 	"testing"
 )
 
+// Is is simplified facsimile of the go 1.13 errors.Is to ensure QueryError is compatible
+func Is(err, target error) bool {
+	for err != nil {
+		if target == err {
+			return true
+		}
+
+		switch e := err.(type) {
+		case interface{ Unwrap() error }:
+			err = e.Unwrap()
+		default:
+			break
+		}
+	}
+	return false
+}
+
 func TestErrorf(t *testing.T) {
 	cause := io.EOF
 
 	t.Run("wrap error", func(t *testing.T) {
 		err := Errorf("boom: %v", cause)
-		if !errors.Is(err, cause) {
+		if !Is(err, cause) {
 			t.Fatalf("expected errors.Is to return true")
 		}
 	})
 
 	t.Run("handles nil", func(t *testing.T) {
 		var err *QueryError
-		if errors.Is(err, cause) {
+		if Is(err, cause) {
 			t.Fatalf("expected errors.Is to return false")
 		}
 	})
 
 	t.Run("handle no arguments", func(t *testing.T) {
 		err := Errorf("boom")
-		if errors.Is(err, cause) {
+		if Is(err, cause) {
 			t.Fatalf("expected errors.Is to return false")
 		}
 	})
 
 	t.Run("handle non-error argument arguments", func(t *testing.T) {
 		err := Errorf("boom: %v", "shaka")
-		if errors.Is(err, cause) {
+		if Is(err, cause) {
 			t.Fatalf("expected errors.Is to return false")
 		}
 	})