Do not discard context from substeps

fixes #487

CHANGELOG.md

@@ -12,6 +12,7 @@ This document is formatted according to the principles of [Keep A CHANGELOG](htt
 - README example is updated with `context.Context` and `go test` usage. ([477](https://github.com/cucumber/godog/pull/477) - [vearutop](https://github.com/vearutop)) 
 
 ### Fixed
+- Fixed a bug which would ignore the context returned from a substep.([488](https://github.com/cucumber/godog/pull/480) - [wichert](https://github.com/wichert))
 - Fixed a bug which would cause a panic when using the pretty formatter with a feature that contained a rule. ([480](https://github.com/cucumber/godog/pull/480) - [dumpsterfireproject](https://github.com/dumpsterfireproject))
 
 ## [v0.12.5]

suite.go

@@ -346,10 +346,12 @@ func (s *suite) maybeSubSteps(ctx context.Context, result interface{}) (context.
 		return ctx, fmt.Errorf("unexpected error, should have been []string: %T - %+v", result, result)
 	}
 
+	var err error
+
 	for _, text := range steps {
 		if def := s.matchStepText(text); def == nil {
 			return ctx, ErrUndefined
-		} else if ctx, err := s.maybeSubSteps(def.Run(ctx)); err != nil {
+		} else if ctx, err = s.maybeSubSteps(def.Run(ctx)); err != nil {
 			return ctx, fmt.Errorf("%s: %+v", text, err)
 		}
 	}