New error for Test classes (Unable to open schema file: C:\opt\snaplogic...)

(Disclaimer: I am not very experienced at Eclipse/Maven/Java, but I can pretty much handle my own with most languages, syntaxes, and IDEs)

My last build for a snap was in December 2018. I have test classes. Everything was successful.

Today, I tried to build (mvn clean install) after a modification to an existing custom snap and my existing (and previously working, unimpacted) test classes are failing with:
java.io.FileNotFoundException: C:\opt\snaplogic\jschema\src\test\resources\schema\com-snaplogic-snap-template_2.schema
for each test class.

I don’t have (and never had) an \opt\snaplogic\ directory and I can’t find reference to it in the POM or any other file in the workspace.

I imagine I need to load/reload a library, reconfigure an eclipse file, or something, but I don’t really know where to start first.

My development platform is Windows 2008 R2 Datacenter, Eclipse 4.7.2 and Maven 3.5.2

Thanks for any help.
– Del