Test: Cargo terminal completions

[dmitrivMS]

Refs: #336216
Implementation PR: #305309

• anyOS

Complexity: 2

Authors: Dmitriy Vasyura (@dmitrivMS), Megan Rogge (@meganrogge)

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A small smoke test of Cargo terminal completions. One OS and one supported shell (bash, zsh, or PowerShell) are sufficient; no exhaustive command, plugin, or toolchain matrix is needed.

Setup

• Use a build containing Add upstream Cargo completion spec for terminal suggestions #305309 (a PR build, or Insiders after it lands), with Rust/Cargo available on PATH.
• Enable terminal.integrated.suggest.enabled and terminal.integrated.shellIntegration.enabled, then open a new integrated terminal.
• Create a disposable project with cargo new cargo-suggest-smoke --bin --vcs none, then cd cargo-suggest-smoke.
• Append this to the generated Cargo.toml:

  [features]
  smoke = []

Use Ctrl+Space (or the terminal's Show Suggestions action) to request suggestions. Include a trailing space when completing an argument value. Use Tab to accept without running the command, then clear the line between checks.

Scenarios

• Subcommands and insertion: At cargo , verify common subcommands such as build, check, run, and test are offered. Type cargo bu and accept build; verify the command becomes cargo build without duplicated text.
• Build options: At cargo build --, verify --release, --features, --package, and --manifest-path are offered. Accept --release and check that the existing command is preserved and is not executed.
• Project-aware values: At cargo build --features , verify smoke is suggested. At cargo build --package , verify cargo-suggest-smoke is suggested. Accept one value and check that it is inserted correctly.
• Manifest file filtering: Create an empty other.toml beside Cargo.toml. At cargo build --manifest-path , verify Cargo's file suggestions include Cargo.toml, not other.toml; directories may still appear. Accept the manifest and verify the inserted path is correct.

For failures, include the OS/shell, the exact command typed, and expected versus actual suggestions. Link reports to this test item and #336216.