error_test.go

package restapi

import (
	"errors"
	"fmt"
	"testing"
)

func TestSentinels_AreDistinct(t *testing.T) {
	t.Parallel()

	all := []error{
		ErrUnknownErrorCode,
		ErrCodeAlreadyRegistered,
		ErrFallbackErrorCodeRegistration,
		ErrInvalidPaginationLimit,
		ErrInvalidPaginationOffset,
		ErrInvalidPaginationPageSize,
		ErrInvalidPaginationPageNumber,
	}
	seen := make(map[string]struct{}, len(all))
	for _, s := range all {
		if s == nil {
			t.Fatal("sentinel is nil")
		}
		msg := s.Error()
		if _, dup := seen[msg]; dup {
			t.Errorf("duplicate sentinel message: %q", msg)
		}
		seen[msg] = struct{}{}
	}
}

func TestSentinels_WrapUnwrapRoundTrip(t *testing.T) {
	t.Parallel()

	wrapped := fmt.Errorf("%w: %d", ErrCodeAlreadyRegistered, 1234)
	if !errors.Is(wrapped, ErrCodeAlreadyRegistered) {
		t.Fatal("wrapped error must satisfy errors.Is on its sentinel")
	}
}

func TestErrInvalidPaginationOffset_Message(t *testing.T) {
	t.Parallel()

	// Regression: the message used to be the copy-pasted "invalid limit".
	if got := ErrInvalidPaginationOffset.Error(); got != "invalid offset" {
		t.Fatalf("got %q; want %q", got, "invalid offset")
	}
}