[docs] Added test guide

[Vineet1101]

This PR adds a comprehensive guide on testing in the P4C repository. The document covers different types of tests, their expected behavior, source file locations, how to run tests, and how to add new tests. Additionally, it includes details on continuous integration and automated test execution.

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[Vineet1101]

@jafingerhut there is no bmv_errors_output directory in the testdata

[jafingerhut]

@jafingerhut there is no bmv_errors_output directory in the testdata

That is true. There is also no directory bmv_errors, either, so why would you expect there to be a directory bmv_errors_output?

[jafingerhut]

@jafingerhut there is no bmv_errors_output directory in the testdata

That is true. There is also no directory bmv_errors, either, so why would you expect there to be a directory bmv_errors_output?

If you mean: "Why is there a directory named p4_16_bmv_errors in the testdata directory, but there is no corresponding expected outputs directory named p4_16_bmv_errors_output?" then my answer is "I don't know".

It would be good to find out, and either correct the problem, or document why one is not necessary. It might be a mistake that there is no directory p4_16_bmv_errors_output.

[Vineet1101]

yes I mean that why there is bmv_errors file but no output No problem I will try to find out why there is no output file

@jafingerhut there is no bmv_errors_output directory in the testdata

That is true. There is also no directory bmv_errors, either, so why would you expect there to be a directory bmv_errors_output?

If you mean: "Why is there a directory named p4_16_bmv_errors in the testdata directory, but there is no corresponding expected outputs directory named p4_16_bmv_errors_output?" then my answer is "I don't know".

It would be good to find out, and either correct the problem, or document why one is not necessary. It might be a mistake that there is no directory p4_16_bmv_errors_output.

[Vineet1101]

@jafingerhut can you please review this
also i could not find the reason why there is no output file for p4_16_bmv_errors so I have not included it in the doc for now

[fruffy]

Not everyone uses make. I would recommend ctest here. If make is recommended somewhere else, I would update it.

[Vineet1101]

added testing using ctest section and remove cmake one

[Vineet1101]

also running test using make is written in the p4 docs so if you want i can update the docs

[Copilot]

Copilot reviewed 1 out of 1 changed files in this pull request and generated 1 comment.

Comments suppressed due to low confidence (2)

docs/AddingTestGuide.md:17

• The source file location for Negative Tests has been removed without a replacement. Please verify if updated directory paths should be provided to ensure clarity for readers.

- `testdata/p4_16_errors/`

docs/AddingTestGuide.md:28

• The Backend-Specific Tests section no longer lists expected source file locations. If these paths have changed, consider updating this section with the current directories to avoid confusion.

- `backends/ebpf/tests/`

[Copilot]

There is a missing space after the period in 'pass.The'; please add a space to improve readability.

Suggested change

	Positive tests are standard tests where the compiler should not fail due to compile-time errors. The expected output should match the actual output for the test to pass.The compiler should generate a output file with no errors.
	Positive tests are standard tests where the compiler should not fail due to compile-time errors. The expected output should match the actual output for the test to pass. The compiler should generate a output file with no errors.

[Vineet1101]

done

[Copilot]

Copilot reviewed 1 out of 1 changed files in this pull request and generated no comments.

Comments suppressed due to low confidence (2)

docs/AddingTestGuide.md:40

• [nitpick] The sentence seems a bit awkward; consider rephrasing it for clarity, for example: 'Similarly, for other error output files, please refer to the corresponding directories.'

Similarly for other error output files you can check 

docs/AddingTestGuide.md:25

• [nitpick] Consider capitalizing 'ubpf' to 'UBPF' for consistency with 'eBPF' to improve clarity.

Some test programs exist in backend-specific directories, such as eBPF, ubpf tests.