Patrice, you are spot on
At my most recent workshop, our instructor had a set of strips for everyone to ensure they are getting their 1/4" seam accurate - and recommended that you have a stack of these ready for every time you sit down to sew, to make sure you *still* have a good 1/4" seam. You can end up making a cute rail fence out of these test strips. Two colours, three strips - 2" x 5". Finished block should be 5" square.
And my best friend - Starch!