test: Fixture sets the testing.TB recursively

When fixtures embed or include fixtures, make sure the TB value is set
on nested fields.

Author: stroiman

internal/testing/exp/fixture/fixture.go

@@ -125,13 +125,21 @@ func (f FixtureSetup[T]) setup(val reflect.Value) Setuper {
 		}
 		setups.append(f.setup(val.FieldByIndex(field.Index)))
 	}
-	if setup, ok := val.Interface().(Setuper); ok {
+	actualVal := val.Interface()
+	if setup, ok := actualVal.(Setuper); ok {
 		setups.append(setup)
 	} else if val.CanAddr() {
 		if setup, ok := val.Addr().Interface().(Setuper); ok {
 			setups.append(setup)
 		}
 	}
+	if init, ok := actualVal.(FixtureInit); ok {
+		init.SetTB(f.TB)
+	} else if val.CanAddr() {
+		if init, ok := val.Addr().Interface().(FixtureInit); ok {
+			init.SetTB(f.TB)
+		}
+	}
 	// var res *NullSetup
 	return setups
 }