Add waddrmgr.IsError function.

waddrmgr/error.go

@@ -204,3 +204,10 @@ func managerError(c ErrorCode, desc string, err error) ManagerError {
 // Break is a global err used to signal a break from the callback
 // function by returning an error with the code ErrCallBackBreak
 var Break = managerError(ErrCallBackBreak, "callback break", nil)
+
+// IsError returns whether the error is a MangerError with a matching error
+// code.
+func IsError(err error, code ErrorCode) bool {
+	e, ok := err.(ManagerError)
+	return ok && e.ErrorCode == code
+}

waddrmgr/error_test.go

@@ -17,6 +17,7 @@
 package waddrmgr_test
 
 import (
+	"errors"
 	"fmt"
 	"testing"
 
@@ -120,3 +121,47 @@ func TestManagerError(t *testing.T) {
 		}
 	}
 }
+
+// TestIsError tests the IsError func.
+func TestIsError(t *testing.T) {
+	tests := []struct {
+		err  error
+		code waddrmgr.ErrorCode
+		exp  bool
+	}{
+		{
+			err: waddrmgr.ManagerError{
+				ErrorCode: waddrmgr.ErrDatabase,
+			},
+			code: waddrmgr.ErrDatabase,
+			exp:  true,
+		},
+		{
+			// package should never return *ManagerError
+			err: &waddrmgr.ManagerError{
+				ErrorCode: waddrmgr.ErrDatabase,
+			},
+			code: waddrmgr.ErrDatabase,
+			exp:  false,
+		},
+		{
+			err: waddrmgr.ManagerError{
+				ErrorCode: waddrmgr.ErrCrypto,
+			},
+			code: waddrmgr.ErrDatabase,
+			exp:  false,
+		},
+		{
+			err:  errors.New("not a ManagerError"),
+			code: waddrmgr.ErrDatabase,
+			exp:  false,
+		},
+	}
+
+	for i, test := range tests {
+		got := waddrmgr.IsError(test.err, test.code)
+		if got != test.exp {
+			t.Errorf("Test %d: got %v expected %v", i, got, test.exp)
+		}
+	}
+}