Junit5 usage applied to solved Foobar functions

(a straightforward personal attempt)

About the repo

The initial aim was solving tasks on my own just for the enjoyment itself (got the invitation, anyway); however, it all turned into a fun opportunity to play around with JUnit test framework. All coding job was made in one-shot way, with a deadline and considering possible time-out errors. Of course, JUnit tests were implemented in a subsequent stage. Thus, if you came here already knowing what Foobar & JUnit are, skip the next section; if it's not the case, keep reading please 🙌.

Foobar challenge

Let's use a ChatGPT shortcut for this explantion step:

Google's Foobar challenge is an invitation-only coding challenge that Google uses to identify and recruit talented programmers (being honest, they probably could offer a sort of internship if you're talent enough; not bad at all, anyway 💪)

It typically appears as a pop-up message on a user's screen when they are searching for coding-related terms on Google (like a creepy surprise; I thought I was being hacked)

Some people have reported receiving an invitation after searching for specific coding-related terms on Google; or have received an invitation through a referral (or looking for how to remove stain from carpet; whichever occurs first)

Junit5 framework

JUnit 5 is a popular open-source testing framework for Java applications. JUnit 5 provides several enhancements and new features making it more powerful and flexible for writing and executing tests.

Brief description of key features used in the current repo:

• Assertions API: offering a wide range of assertion methods for validating results.
• Parameterized Tests: allowing to write repeated testing with different sets of test data.
• Conditional Test Execution: concept of conditional test execution based on custom or predefined conditions.
• Test Instance Lifecycle: giving more control over resource management and test isolation.
• Test Execution Order: letting to define custom test execution orders by needs.
• Nested Tests: permitting to group related tests within a same test class, structuring methods in a hierarchical manner.
• Tagging and Filtering: enabling the capability of selectively execution based on categorizing.

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Built with

Additional info

• Where possible, It has been done with plain readable java; no streams used (clean code, I mean).
• Each task constructor was renamed using suffixes (ex: solution1, solution2 and so forth) to include them in a single class.
• Added more test cases (besides those originally given), including extreme ones to avoid long execution times.
• For a more in-depth understanding of the implemented code, as many comments as possible have been included.
• No intention of winning the code-of-the-year championship; readability was weighted over micro-optimization.

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Implementation details

Selected foobar challanges

Test	Challenge name	Input data type	Output data type	Testing Status
1	Square Supplies	int	int	✔
2	Zombit Monitoring	int[ ][ ]	int	✔
3	Palindrome	int	int	✔
4	Zombit Antidote	int[ ][ ]	int	✔
5	Please Pass The Coded Messages	int[ ]	String	✔
6	Re-ID	int	String	✔
7	Zombit Infection	int[ ][ ], int, int, int	int[ ][ ]	✔

Junit5 version

Used annotations

• @Nested (allowing to test several outer classes (challenges), actually inside the same main test class).
• @ParameterizedTest (addressing the run of same test passing several groups of parameters).
• @CsvSource (arguments source, as strings &/or ints).
• @ValueSource (arguments source, as strings or ints).
• @MethodSource (arguments source, as multidimensional arrays of ints).
• @TestInstance (PER_CLASS; enabling one single instance of the test class reusable for all method).
• @Order (just for the sake of completeness, highly discouraged; switching the timeout test execution for the last).
• @DisplayName (on classes & methods; see left figure).
• @EnabledIf (allowing to skip a test if a true condition is not satisfied; see right figure).
• @BeforeEach (displaying on screen the timestamp & test info; see bottom figure).
• @Tag (identifies each test class for display info purposes).

Implemented utility methods

• assertEquals (checking against expected; input as int || String).
• assertArrayEquals (checking against expected; input as multidimensional arrays, int[ ][ ]).
• assertTimeout (seeking for timeout errors).
• assertTrue (rejecting null & strings, including empty values).
• arguments.of(Object ...) (input source; as multidimensional arrays of ints or strings).

Screenshots of tests runs results

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License

Distributed under the MIT License. See LICENSE.txt for more information.

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