Prior to this commit, it was impossible to include a placeholder (i.e.,
${placeholder.name}) in a Properties file location configured via
@TestPropertySource if the placeholder was immediately followed by a
relative path (i.e., "../"). This was due to the fact that the location
was always cleaned using StringUtils.cleanPath(), which removed the
placeholder and the relative path syntax.
This commit fixes this by preserving all placeholders in
@TestPropertySource locations by simply not cleaning the locations if
they contain placeholders.
Closes gh-23544
ab779eb431