What does this PR do?

Six of the tests in tests/integration/test_modal_terminal.py used:

success = <condition>
...
return success

Pytest treats a returned value as a warning, not a failure. Every one of these tests has been reported as PASSED regardless of whether Modal actually worked — the file was effectively a no-op under pytest, masking real Modal terminal regressions.

Fix:

• Replace return success / return isolated / return requirements_met with assert <value>, <diagnostic message>. The diagnostic includes exit code and error text so a CI failure is actionable.
• Replace the TERMINAL_ENV != modal → return False in test_modal_requirements() with pytest.skip(...), which is the correct signal when a precondition isn't met. The test is no longer misreported as PASSED when Modal isn't configured — it's cleanly skipped.
• Keep the imperative main() runner usable (for the python tests/integration/test_modal_terminal.py usage the module docstring advertises). Rewrote it to tolerate AssertionError / pytest.skip.Exception and classify each test as PASSED / FAILED / SKIPPED in the summary.

Related Issue

Fixes #13286

Type of Change

• ✅ Tests (adding or improving test coverage)

Changes Made

• tests/integration/test_modal_terminal.py (+52 / −29): every test now ends with assert ..., <diagnostic>; test_modal_requirements uses pytest.skip(); main() rewritten to classify exceptions.

-    if config['env_type'] != 'modal':
-        print(...)
-        return False
+    if config['env_type'] != 'modal':
+        print(...)
+        pytest.skip(f"TERMINAL_ENV='{config['env_type']}', skipping Modal-specific test")
...
-    return success
+    assert success, f"Simple command failed: exit={result_json.get('exit_code')}, error={result_json.get('error')}"

How to Test

1. pytest tests/integration/test_modal_terminal.py -q with TERMINAL_ENV unset → all tests reported SKIPPED (was: all PASSED silently).
2. TERMINAL_ENV=modal pytest tests/integration/test_modal_terminal.py -q → real pass/fail based on Modal behavior.
3. python tests/integration/test_modal_terminal.py → still works as a script runner with PASSED/FAILED/SKIPPED classification.

Checklist

Code

• I've read the Contributing Guide
• My commit messages follow Conventional Commits (fix(tests):)
• I searched for existing PRs to make sure this isn't a duplicate
• My PR contains only changes related to this fix
• I've run pytest tests/ -q and all tests pass
• I've added tests for my changes — N/A (fixes existing tests to actually assert)
• I've tested on my platform: macOS 26.5 (arm64)

Documentation & Housekeeping

• Documentation updates — N/A
• cli-config.yaml.example — N/A
• CONTRIBUTING.md / AGENTS.md — N/A
• Cross-platform impact considered — pytest/stdlib only
• Tool descriptions/schemas — N/A

Not in scope

• Bug: tests/integration/test_web_tools.py is named like a pytest module but collects zero tests #13287 (test_web_tools.py collects 0 tests) — addressed by a different PR.
• Reworking these tests into proper @pytest.mark.modal fixtures with conftest auto-skip — would be a larger refactor; this PR intentionally stays minimal.

Screenshots / Logs

• python3 -m py_compile tests/integration/test_modal_terminal.py → clean.
• Walked the file top to bottom, confirmed all six test bodies now end with an assert carrying a descriptive message, and that test_modal_requirements() uses pytest.skip() instead of return False when TERMINAL_ENV != "modal".