[test] Bug in StringSubstitutor?

[Gary Gregory]

Hi All:

I think we might have a bug in StringSubstitutor exemplified in a comment I
just added in:

org.apache.commons.text.StringSubstitutorTest.testReplaceWeirdPattens()

        doTestNoReplace("${");
        // TODO this looks like a bug since a $ is removed but this is not
a variable.
        // doTestNoReplace("$${");
        // doTestNoReplace("$${a");
        // doTestNoReplace("$$${");
        // doTestNoReplace("$$${a");

I thought that we would only strip $ in front of a _complete_ variable, not
anywhere in front of a variable _prefix_.

Granted this is an edge case but still...

Any thoughts?

Gary