filed as reference, as the issue appears to be known<<
Describe the bug
When building eXist-db on macOS, the tests of the file module fails:

Expected behavior
A build should be consistently OK on all platforms
To Reproduce
mvn clean install
Screenshots
[INFO]
[INFO] ----------------------< org.exist-db:exist-file >-----------------------
[INFO] Building eXist-db File Module 5.3.0-SNAPSHOT [25/48]
[INFO] --------------------------------[ jar ]---------------------------------
[INFO]
[INFO] --- maven-clean-plugin:3.1.0:clean (default-clean) @ exist-file ---
[INFO] Deleting /Users/wessels/Development/github/exist/extensions/modules/file/target
[INFO]
[INFO] --- buildversion-plugin:1.0.3:set-properties (default) @ exist-file ---
[INFO]
[INFO] --- maven-resources-plugin:3.2.0:resources (default-resources) @ exist-file ---
[INFO] Using 'UTF-8' encoding to copy filtered resources.
[INFO] Using 'UTF-8' encoding to copy filtered properties files.
[INFO] Copying 1 resource
[INFO]
[INFO] --- maven-compiler-plugin:3.8.1:compile (default-compile) @ exist-file ---
[INFO] Changes detected - recompiling the module!
[INFO] Compiling 17 source files to /Users/wessels/Development/github/exist/extensions/modules/file/target/classes
[INFO] /Users/wessels/Development/github/exist/extensions/modules/file/src/main/java/org/exist/xquery/modules/file/Sync.java: Some input files use or override a deprecated API.
[INFO] /Users/wessels/Development/github/exist/extensions/modules/file/src/main/java/org/exist/xquery/modules/file/Sync.java: Recompile with -Xlint:deprecation for details.
[INFO]
[INFO] --- maven-resources-plugin:3.2.0:testResources (default-testResources) @ exist-file ---
[INFO] Using 'UTF-8' encoding to copy filtered resources.
[INFO] Using 'UTF-8' encoding to copy filtered properties files.
[INFO] Copying 3 resources
[INFO] Copying 1 resource
[INFO]
[INFO] --- maven-compiler-plugin:3.8.1:testCompile (default-testCompile) @ exist-file ---
[INFO] Changes detected - recompiling the module!
[INFO] Compiling 5 source files to /Users/wessels/Development/github/exist/extensions/modules/file/target/test-classes
[INFO]
[INFO] --- maven-surefire-plugin:3.0.0-M4:test (default-test) @ exist-file ---
[INFO]
[INFO] -------------------------------------------------------
[INFO] T E S T S
[INFO] -------------------------------------------------------
[INFO] Running xquery.modules.file.FileTests
[INFO] Running org.exist.xquery.modules.file.EmbeddedBinariesTest
[INFO] Running org.exist.xquery.modules.file.XmldbBinariesTest
[INFO] Running org.exist.xquery.modules.file.RestBinariesTest
[ERROR] Tests run: 1, Failures: 0, Errors: 1, Skipped: 0, Time elapsed: 2.109 s <<< FAILURE! - in org.exist.xquery.modules.file.XmldbBinariesTest
[ERROR] org.exist.xquery.modules.file.XmldbBinariesTest Time elapsed: 2.062 s <<< ERROR!
java.nio.file.FileSystemNotFoundException
[ERROR] Tests run: 1, Failures: 0, Errors: 1, Skipped: 0, Time elapsed: 2.146 s <<< FAILURE! - in org.exist.xquery.modules.file.RestBinariesTest
[ERROR] org.exist.xquery.modules.file.RestBinariesTest Time elapsed: 2.132 s <<< ERROR!
java.nio.file.FileSystemNotFoundException
[INFO] Tests run: 2, Failures: 0, Errors: 0, Skipped: 0, Time elapsed: 4.383 s - in org.exist.xquery.modules.file.EmbeddedBinariesTest
[WARNING] Tests run: 3, Failures: 0, Errors: 0, Skipped: 3, Time elapsed: 5.184 s - in xquery.modules.file.FileTests
[INFO]
[INFO] Results:
[INFO]
[ERROR] Errors:
[ERROR] RestBinariesTest 禄 FileSystemNotFound
[ERROR] XmldbBinariesTest 禄 FileSystemNotFound
[INFO]
[ERROR] Tests run: 7, Failures: 0, Errors: 2, Skipped: 3
the FileSystemNotFoundException is suspicious, on StackOverflow loading resources from class path is mentioned but that does not seem to be relevant here. There is no line number in the error, which might give an hint that the issue occurs very early, e.g. during static initialisation or so.
What funny/interesting is... a File-related issues occurs in... a file-handling module :-/
Context (please always complete the following information):
Apache Maven 3.6.3 (cecedd343002696d0abb50b32b541b8a6ba2883f)
Maven home: /usr/local/Cellar/maven/3.6.3_1/libexec
Java version: 1.8.0_275, vendor: BellSoft, runtime: /Library/Java/JavaVirtualMachines/liberica-jdk-8-full.jdk/Contents/Home/jre
Default locale: en_NL, platform encoding: UTF-8
OS name: "mac os x", version: "10.16", arch: "x86_64", family: "mac"
Additional context
n/a
@dizzzz finally able to reproduce this issue on my Mac too. I will look into that further in the next days
Most helpful comment
@dizzzz finally able to reproduce this issue on my Mac too. I will look into that further in the next days