Add unit tests for OutputHelper class #736

Job	Run time
checkstyle	3m 28s
shellcheck	3m 9s
build	5m 9s
copyright	3m 14s
spotbugs	5m 18s
javadoc	4m 6s
tests/cli-linux	3m 22s
cli/linux-amd64	4m 38s
cli/windows-amd64	5m 35s
tests/cli-functional-linux	3m 39s
vscode-ext	3m 52s
cli/darwin-amd64	5m 26s
tests/archetype-linux	3m 42s
tests/linker-linux	3m 40s
tests/others-linux	3m 41s
tests/cli-windows	3m 24s
tests/cli-functional-windows	3m 25s
tests/archetype-windows	3m 25s
tests/linker-windows	3m 22s
tests/others-windows	3m 21s
cli/binaries	7s
tests/results	0s
gate	0s
	1h 19m 3s

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