Function TestSimultaneousMigration

errbase/migrations_test.go:138–169

Scenario 2: simultaneous migration - vA renames foo -> bar vA calls RegisterTypeMigration("foo", (*bar)(nil)) - vB renames foo -> qux vB calls RegisterTypeMigration("foo", (*qux)(nil)) - vA and vB are connected - vA sends an error to vB: - vA translates the error key upon send from bar to foo's key

(t *testing.T)

//   - vA translates the error key upon send from bar to foo's key
//   - vB recognizes that "foo" refers to qux
func TestSimultaneousMigration(t *testing.T) {
	// == Scenario on vA ==
	defer errbase.TestingWithEmptyMigrationRegistry()()
	origErr := barErr{}
	// Register the fact that foo was migrated to bar.
	errbase.RegisterTypeMigration(myPkgPath, "errbase_test.fooErr", origErr)
	// Send the error to vB.
	enc := errbase.EncodeError(context.Background(), origErr)
	// Clean up the decoder, so that type becomes unknown for further tests.
	errbase.RegisterLeafDecoder(errbase.GetTypeKey(origErr), nil)
	// Erase the migration we have set up above, so that the test
	// underneath does not know about it.
	defer errbase.TestingWithEmptyMigrationRegistry()()

	// == Scenario on v2 ==
	defer errbase.TestingWithEmptyMigrationRegistry()()
	// Register the fact that foo was migrated to qux.
	errbase.RegisterTypeMigration(myPkgPath, "errbase_test.fooErr", quxErr{})
	// Register the qux decoder.
	errbase.RegisterLeafDecoder(errbase.GetTypeKey(quxErr{}),
		func(_ context.Context, _ string, _ []string, _ proto.Message) error { return quxErr{} })
	// Receive the error from vA.
	dec := errbase.DecodeError(context.Background(), enc)
	// Clean up, so that type qux becomes unknown for further tests.
	errbase.RegisterLeafDecoder(errbase.GetTypeKey(quxErr{}), nil)

	// Main test: check that vA normalized the bar error to foo,
	// and v2 instantiated it as qux.
	if _, ok := dec.(quxErr); !ok {
		t.Errorf("migration failed; expected type quxErr, got %T", dec)
	}
}

// Scenario 3: migrated error passing through
// - v2 renames foo -> bar