Rust: Split up the dataflow/sources test

[geoffw0]

Split up the dataflow/sources test. It had become quite large, with lots of dependencies, which was making it slow to work with locally.

[Copilot]

Pull Request Overview

This PR reorganizes the dataflow/sources test suite by splitting a large monolithic test into smaller, more focused test suites organized by source type. This improves local development workflow by reducing dependencies and compilation times.

Key changes:

• Split the original dataflow/sources test into multiple focused test directories
• Created separate test suites for: web frameworks, stdin, networking, file I/O, environment variables, and database sources
• Maintained test coverage while improving modularity

Reviewed Changes

Copilot reviewed 44 out of 54 changed files in this pull request and generated no comments.

Show a summary per file

File	Description
web_frameworks/test.rs	(Implied) Test cases for web framework data sources
web_frameworks/*.qlref	Query references for web framework taint source tests
web_frameworks/*.expected	Expected test results for web framework sources
stdin/test.rs	Test cases for standard input data sources
stdin/*.qlref	Query references for stdin taint source tests
stdin/*.expected	Expected test results for stdin sources
net/test.rs	Test cases for network-related data sources (HTTP, TCP)
net/options.yml	Reduced dependency list, removed web framework dependencies
net/*.qlref	Query references for network taint source tests
net/*.expected	Expected test results for network sources
file/test.rs	Test cases for file system data sources
file/options.yml	Dependencies for file I/O tests
file/*.qlref	Query references for file taint source tests
env/test.rs	Test cases for environment variable and command-line argument sources
env/options.yml	Minimal dependencies for environment tests
env/*.qlref	Query references for environment taint source tests
database/test.rs	Test cases for database query result sources
database/options.yml	Dependencies for MySQL database tests
database/*.qlref	Query references for database taint source tests
test.rs	(Deleted) Original monolithic test file
test_futures_io.rs	(Deleted) Moved to net directory
reqwest.rs	(Deleted) Stub file removed

[hvitved]

Can we please wait until #20282 is merged? I have already had to rebase that PR multiple times because of exactly this test.

[geoffw0]

Can we please wait until #20282 is merged?

Yes, if we get that merged soon. Fixing merge conflicts here is going to be a bit of a pain, I tried to pick a quiet time for it.

[hvitved]

Yes, if we get that merged soon.

Has now been merged.

[geoffw0]

I've merged in main (with #20282). Had to do a bit of manual fixup. There had been two results lost in this PR (I hypothesised because of something about their context changing), we get them back now! :)

I would appreciate review and approval of this work as soon as possible, assuming there are no big objections. Otherwise difficult merge conflicts are going to keep happening due to the nature of this change.

[paldepind]

Thanks for doing this 👍