test: add assertion for executing App.main with empty args

[AlMartinezUy]

Pull Request Template

What does this PR do?

This PR adds an additional assertion to the AppTest test class in the
abstract-document module. The new assertion verifies that calling
App.main with an empty String[] argument does not throw any exception.

This complements the existing assertion that checks the behavior when the
main method is invoked with a null argument.

No production code is modified. This PR solely improves test coverage and
validates expected behavior under different argument conditions.

[github-actions]

⏳ Analyzing changes in this PR... ⏳

This might take a few minutes, please wait

📥 Commits

Analyzing changes from base (ede37bd) to latest commit (2169fe9):

• 2169fe9: test: add assertion for executing App.main with empty args
• 664b5f7: Fix duplicated README formatting: separate Introduction and Getting Started sections

📁 Files being considered (2)

🔄 README.md (1 hunk)
🔄 abstract-document/src/test/java/com/iluwatar/abstractdocument/AppTest.java (1 hunk)

---

autogenerated by presubmit.ai

[AlMartinezUy]

Hi! I noticed that the checks failed, but the failure appears unrelated to the
changes in this PR. The modification only affects a small test case in the
abstract-document module.

Please let me know if you'd like me to adjust anything.