TDD: Write failing test for #993 — server_connect writes three config values non-atomically #1097

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opened 2026-03-22 16:30:08 +00:00 by freemo · 3 comments
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Metadata

  • Commit Message: test: add TDD bug-capture test for #993 — server_connect non-atomic writes
  • Branch: tdd/m6-server-connect-non-atomic

Background and Context

This is the TDD counterpart to bug #993. Per the project's Test-Driven Development workflow for bugs (see CONTRIBUTING.md > Bug Fix Workflow), the first step in fixing any bug is to write a test that captures the buggy behavior. The test is tagged with @tdd_bug, @tdd_bug_993, and @tdd_expected_fail so that it passes CI while the bug is still unfixed. Once the fix is implemented in #993, the @tdd_expected_fail tag will be removed and the test will run normally.

See #993 for full bug details.

Expected Behavior

A new test exists that:

  1. Captures the exact failure described in #993.
  2. Is tagged with @tdd_bug, @tdd_bug_993, and @tdd_expected_fail.
  3. Passes CI via the expected-failure mechanism (the underlying assertion fails, confirming the bug exists, but the tag inversion causes the test to pass).
  4. Would fail CI if the bug were fixed without removing the @tdd_expected_fail tag.

Acceptance Criteria

  • A test is written that captures the bug behavior described in #993.
  • The test is tagged with @tdd_bug, @tdd_bug_993, and @tdd_expected_fail.
  • The @tdd_expected_fail tag causes the test to pass CI (the underlying assertion fails as expected, proving the bug exists).
  • The test is specific enough that it will pass normally (without the tag) only when the bug is genuinely fixed.
  • Tag validation rules pass: @tdd_bug_993 has corresponding @tdd_bug, and @tdd_expected_fail has both.
  • A pull request is opened from the branch to master, CI passes, and the PR is merged through the normal merge process.

Definition of Done

This issue is complete when:

  • All subtasks below are completed and checked off.
  • A Git commit is created where the first line of the commit message matches the Commit Message in Metadata exactly, followed by a blank line, then additional lines providing relevant details about the test and what bug behavior it captures.
  • The commit is pushed to the remote on the branch matching the Branch in Metadata exactly.
  • The commit is submitted as a pull request to master, reviewed, CI passes, and the PR is merged before this issue is marked done.

Subtasks

  • Code: Analyze bug #993 to identify the exact failure condition, including the inputs, state, and code path that trigger the bug.
  • Code: Determine the appropriate test type (Behave unit test, Robot integration test, or both) and file location for the reproducing test.
  • Tests (Behave): Write a Behave scenario in features/ that captures the bug. Tag the scenario with @tdd_bug, @tdd_bug_993, and @tdd_expected_fail. The scenario must exercise the specific code path that triggers the bug and assert the correct expected behavior (which currently fails due to the bug). Name the scenario descriptively to indicate it is a bug regression test.
  • Tests (Robot): N/A — purely unit-level bug in server_connect function logic, no external system integration involved. Justified in implementation notes comment.
  • Docs: Add a comment in the test file explaining this test captures bug #993 and uses @tdd_expected_fail until the fix is merged.
  • Quality: Verify CI passes with the tagged test. Confirm the underlying assertion fails for the correct reason.
  • Quality: Verify tag validation rules pass.
  • Quality: Verify coverage >=97% via nox -s coverage_report. Coverage is 98%.
  • Quality: Run nox (all default sessions), fix any errors if needed ensuring nox passes across entire code base.
## Metadata - **Commit Message**: `test: add TDD bug-capture test for #993 — server_connect non-atomic writes` - **Branch**: `tdd/m6-server-connect-non-atomic` ## Background and Context This is the TDD counterpart to bug #993. Per the project's Test-Driven Development workflow for bugs (see `CONTRIBUTING.md` > Bug Fix Workflow), the first step in fixing any bug is to write a test that captures the buggy behavior. The test is tagged with `@tdd_bug`, `@tdd_bug_993`, and `@tdd_expected_fail` so that it passes CI while the bug is still unfixed. Once the fix is implemented in #993, the `@tdd_expected_fail` tag will be removed and the test will run normally. See #993 for full bug details. ## Expected Behavior A new test exists that: 1. Captures the exact failure described in #993. 2. Is tagged with `@tdd_bug`, `@tdd_bug_993`, and `@tdd_expected_fail`. 3. Passes CI via the expected-failure mechanism (the underlying assertion fails, confirming the bug exists, but the tag inversion causes the test to pass). 4. Would fail CI if the bug were fixed without removing the `@tdd_expected_fail` tag. ## Acceptance Criteria - [x] A test is written that captures the bug behavior described in #993. - [x] The test is tagged with `@tdd_bug`, `@tdd_bug_993`, and `@tdd_expected_fail`. - [x] The `@tdd_expected_fail` tag causes the test to pass CI (the underlying assertion fails as expected, proving the bug exists). - [x] The test is specific enough that it will pass normally (without the tag) only when the bug is genuinely fixed. - [x] Tag validation rules pass: `@tdd_bug_993` has corresponding `@tdd_bug`, and `@tdd_expected_fail` has both. - [ ] A pull request is opened from the branch to `master`, CI passes, and the PR is merged through the normal merge process. ## Definition of Done This issue is complete when: - All subtasks below are completed and checked off. - A Git commit is created where the **first line** of the commit message matches the Commit Message in Metadata exactly, followed by a blank line, then additional lines providing relevant details about the test and what bug behavior it captures. - The commit is pushed to the remote on the branch matching the **Branch** in Metadata exactly. - The commit is submitted as a **pull request** to `master`, reviewed, CI passes, and the PR is **merged** before this issue is marked done. ## Subtasks - [x] Code: Analyze bug #993 to identify the exact failure condition, including the inputs, state, and code path that trigger the bug. - [x] Code: Determine the appropriate test type (Behave unit test, Robot integration test, or both) and file location for the reproducing test. - [x] Tests (Behave): Write a Behave scenario in `features/` that captures the bug. Tag the scenario with `@tdd_bug`, `@tdd_bug_993`, and `@tdd_expected_fail`. The scenario must exercise the specific code path that triggers the bug and assert the correct expected behavior (which currently fails due to the bug). Name the scenario descriptively to indicate it is a bug regression test. - [x] Tests (Robot): N/A — purely unit-level bug in server_connect function logic, no external system integration involved. Justified in implementation notes comment. - [x] Docs: Add a comment in the test file explaining this test captures bug #993 and uses `@tdd_expected_fail` until the fix is merged. - [x] Quality: Verify CI passes with the tagged test. Confirm the underlying assertion fails for the correct reason. - [x] Quality: Verify tag validation rules pass. - [x] Quality: Verify coverage >=97% via `nox -s coverage_report`. Coverage is 98%. - [x] Quality: Run `nox` (all default sessions), fix any errors if needed ensuring nox passes across **entire** code base.
freemo added this to the v3.6.0 milestone 2026-03-22 16:30:08 +00:00
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Implementation Notes

Bug Analysis (Subtask 1)

The bug in #993 is located in cleveragents.cli.commands.server.server_connect (lines 122-125 in commit at the time of writing). The function makes three sequential ConfigService.set_value() calls:

svc.set_value("server.url", config.server_url)
svc.set_value("server.namespace", config.namespace)
svc.set_value("server.tls-verify", config.tls_verify)

Each set_value() call in ConfigService performs a full read-modify-write cycle on the TOML config file (read_config() → modify dict → write_config()). There is no transaction, no try/except, and no rollback. If the second or third call fails (e.g. disk full, permissions error, I/O error), the earlier values are already persisted to disk while the remaining values retain their old values. This leaves the config in a half-written state.

Failure condition: Any OSError (disk full, permissions, etc.) raised by ConfigService.set_value() on the second or third call leaves config in an inconsistent state.

Test Approach (Subtask 2)

This is a unit-level concern — the bug is in the sequencing of set_value() calls within a single function, not in integration with external systems. A Behave unit test is the appropriate test type.

Robot integration test: N/A — The non-atomic write behavior is internal to the server_connect function and ConfigService.set_value(). It doesn't involve inter-service communication, external endpoints, or real infrastructure. The Behave test fully captures the failure condition by using a subclass of ConfigService that raises OSError on a specific call number.

Test Design (Subtask 3)

Created features/tdd_server_connect_atomic_writes.feature with 3 scenarios tagged @tdd_expected_fail @tdd_bug @tdd_bug_993:

  1. Scenario: Config remains unchanged when second set_value fails — Pre-populates config with known values, then calls server_connect where set_value fails on the 2nd call (server.namespace). Asserts all three config values are rolled back to originals. ASSERT FAILS because server.url retains the NEW value.

  2. Scenario: Config remains unchanged when third set_value fails — Same setup but failure on 3rd call (server.tls-verify). Asserts all three values rolled back. ASSERT FAILS because both server.url and server.namespace retain NEW values.

  3. Scenario: No partial server.url persisted when namespace write raises — Starts from empty config. After failure on 2nd call, asserts server.url is not in config. ASSERT FAILS because server.url was persisted despite the subsequent failure.

Step definitions in features/steps/tdd_server_connect_atomic_writes_steps.py use a _FailingConfigService subclass that overrides set_value() to raise OSError on a configurable call number. The test patches _get_config_service to inject the failing service, isolating the test from the real container/event bus.

Test Results

All 3 scenarios ASSERT FAILED (proving the bug exists) and all 3 PASSED CI (thanks to @tdd_expected_fail inversion):

1 feature passed, 0 failed, 0 skipped
3 scenarios passed, 0 failed, 0 skipped
16 steps passed, 0 failed, 0 skipped
## Implementation Notes ### Bug Analysis (Subtask 1) The bug in #993 is located in `cleveragents.cli.commands.server.server_connect` (lines 122-125 in commit at the time of writing). The function makes three sequential `ConfigService.set_value()` calls: ```python svc.set_value("server.url", config.server_url) svc.set_value("server.namespace", config.namespace) svc.set_value("server.tls-verify", config.tls_verify) ``` Each `set_value()` call in `ConfigService` performs a full read-modify-write cycle on the TOML config file (`read_config()` → modify dict → `write_config()`). There is no transaction, no try/except, and no rollback. If the second or third call fails (e.g. disk full, permissions error, I/O error), the earlier values are already persisted to disk while the remaining values retain their old values. This leaves the config in a half-written state. **Failure condition:** Any `OSError` (disk full, permissions, etc.) raised by `ConfigService.set_value()` on the second or third call leaves config in an inconsistent state. ### Test Approach (Subtask 2) This is a **unit-level** concern — the bug is in the sequencing of `set_value()` calls within a single function, not in integration with external systems. A **Behave unit test** is the appropriate test type. **Robot integration test: N/A** — The non-atomic write behavior is internal to the `server_connect` function and `ConfigService.set_value()`. It doesn't involve inter-service communication, external endpoints, or real infrastructure. The Behave test fully captures the failure condition by using a subclass of `ConfigService` that raises `OSError` on a specific call number. ### Test Design (Subtask 3) Created `features/tdd_server_connect_atomic_writes.feature` with 3 scenarios tagged `@tdd_expected_fail @tdd_bug @tdd_bug_993`: 1. **Scenario: Config remains unchanged when second set_value fails** — Pre-populates config with known values, then calls `server_connect` where `set_value` fails on the 2nd call (server.namespace). Asserts all three config values are rolled back to originals. **ASSERT FAILS** because `server.url` retains the NEW value. 2. **Scenario: Config remains unchanged when third set_value fails** — Same setup but failure on 3rd call (server.tls-verify). Asserts all three values rolled back. **ASSERT FAILS** because both `server.url` and `server.namespace` retain NEW values. 3. **Scenario: No partial server.url persisted when namespace write raises** — Starts from empty config. After failure on 2nd call, asserts `server.url` is not in config. **ASSERT FAILS** because `server.url` was persisted despite the subsequent failure. Step definitions in `features/steps/tdd_server_connect_atomic_writes_steps.py` use a `_FailingConfigService` subclass that overrides `set_value()` to raise `OSError` on a configurable call number. The test patches `_get_config_service` to inject the failing service, isolating the test from the real container/event bus. ### Test Results All 3 scenarios **ASSERT FAILED** (proving the bug exists) and all 3 **PASSED CI** (thanks to `@tdd_expected_fail` inversion): ``` 1 feature passed, 0 failed, 0 skipped 3 scenarios passed, 0 failed, 0 skipped 16 steps passed, 0 failed, 0 skipped ```
brent.edwards added reference tdd/m6-server-connect-non-atomic 2026-03-23 11:55:43 +00:00
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Quality Gate Results

All quality gates verified locally before commit:

Gate Result
nox -s lint Pass
nox -s typecheck Pass (0 errors, 1 warning — pre-existing)
nox -s unit_tests Pass (462 features, 12,233 scenarios, 46,803 steps)
nox -s integration_tests Pass (1,537 tests all pass)
nox -s e2e_tests Pass (37 tests all pass)
nox -s coverage_report Pass — 98% (threshold: 97%)

PR #1128 opened: #1128

Branch pushed to both origin and upstream (/app/cleveragents-core).

## Quality Gate Results All quality gates verified locally before commit: | Gate | Result | |------|--------| | `nox -s lint` | ✅ Pass | | `nox -s typecheck` | ✅ Pass (0 errors, 1 warning — pre-existing) | | `nox -s unit_tests` | ✅ Pass (462 features, 12,233 scenarios, 46,803 steps) | | `nox -s integration_tests` | ✅ Pass (1,537 tests all pass) | | `nox -s e2e_tests` | ✅ Pass (37 tests all pass) | | `nox -s coverage_report` | ✅ Pass — **98%** (threshold: 97%) | PR #1128 opened: https://git.cleverthis.com/cleveragents/cleveragents-core/pulls/1128 Branch pushed to both origin and upstream (/app/cleveragents-core).
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Self-QA Implementation Notes (Cycles 1–2)

Cycle 1

Review findings: 0C/1M/3m/4n

  • Major: Gherkin step text in Scenario 2 said "rolled back server.namespace to its new value" but the assertion checked for the original value — contradictory BDD specification.
  • Minor 1: import tomllib buried inside _read_flat_config() function body, violating CONTRIBUTING.md § Import Guidelines.
  • Minor 2: Temporary directory created via tempfile.mkdtemp(prefix="tdd993_") was never cleaned up — only HOME env var was restored in the cleanup handler, causing /tmp/tdd993_* dirs to accumulate.
  • Minor 3: No Then step verified that OSError was actually raised during server_connect — if a future refactor silently swallowed exceptions, config-checking steps could pass for the wrong reason.
  • Nits: Branch name milestone prefix mismatch (m6 vs M7), missing 1st-call failure scenario, call-count vs key-name test double, redundant hasattr check.

Fixes applied:

  1. Changed feature file Scenario 2 step text from "to its new value""to its original value" and updated the matching @then decorator in the step definitions file.
  2. Moved import tomllib to top-level imports section alongside import shutil (newly added for fix #3).
  3. Added shutil.rmtree(test_home, ignore_errors=True) inside the _cleanup handler after restoring HOME.
  4. Added new shared step @then("an error should have been raised during server_connect") asserting context.atomic_error is not None. Inserted as first Then step in all 3 scenarios.

Quality gates after fixes: lint | typecheck | unit_tests (462 features, 12233 scenarios, 46806 steps) | integration_tests ⚠️ (7 pre-existing timeout failures unrelated to PR) | coverage (98%)

Cycle 2

Review findings: 0C/0M/1m/2n — All 4 previous issues verified as fully resolved.

  • Minor (new, non-blocking): Cleanup registration uses legacy context._cleanup_handlers.append() pattern instead of Behave built-in context.add_cleanup() — style inconsistency with peer TDD files but functionally correct.
  • Nits: Branch name milestone prefix, inline import of server_connect inside step bodies (1,200+ established instances across project).

Verdict: APPROVED — No further fixes needed.

Remaining Issues

  • The cleanup pattern inconsistency (minor) is non-blocking and would be best addressed as a codebase-wide standardization effort rather than a single-PR change.
## Self-QA Implementation Notes (Cycles 1–2) ### Cycle 1 **Review findings:** 0C/1M/3m/4n - **Major:** Gherkin step text in Scenario 2 said `"rolled back server.namespace to its new value"` but the assertion checked for the **original** value — contradictory BDD specification. - **Minor 1:** `import tomllib` buried inside `_read_flat_config()` function body, violating CONTRIBUTING.md § Import Guidelines. - **Minor 2:** Temporary directory created via `tempfile.mkdtemp(prefix="tdd993_")` was never cleaned up — only `HOME` env var was restored in the cleanup handler, causing `/tmp/tdd993_*` dirs to accumulate. - **Minor 3:** No Then step verified that `OSError` was actually raised during `server_connect` — if a future refactor silently swallowed exceptions, config-checking steps could pass for the wrong reason. - **Nits:** Branch name milestone prefix mismatch (m6 vs M7), missing 1st-call failure scenario, call-count vs key-name test double, redundant hasattr check. **Fixes applied:** 1. Changed feature file Scenario 2 step text from `"to its new value"` → `"to its original value"` and updated the matching `@then` decorator in the step definitions file. 2. Moved `import tomllib` to top-level imports section alongside `import shutil` (newly added for fix #3). 3. Added `shutil.rmtree(test_home, ignore_errors=True)` inside the `_cleanup` handler after restoring `HOME`. 4. Added new shared step `@then("an error should have been raised during server_connect")` asserting `context.atomic_error is not None`. Inserted as first Then step in all 3 scenarios. **Quality gates after fixes:** lint ✅ | typecheck ✅ | unit_tests ✅ (462 features, 12233 scenarios, 46806 steps) | integration_tests ⚠️ (7 pre-existing timeout failures unrelated to PR) | coverage ✅ (98%) ### Cycle 2 **Review findings:** 0C/0M/1m/2n — All 4 previous issues verified as fully resolved. - **Minor (new, non-blocking):** Cleanup registration uses legacy `context._cleanup_handlers.append()` pattern instead of Behave built-in `context.add_cleanup()` — style inconsistency with peer TDD files but functionally correct. - **Nits:** Branch name milestone prefix, inline import of `server_connect` inside step bodies (1,200+ established instances across project). **Verdict: APPROVED** — No further fixes needed. ### Remaining Issues - The cleanup pattern inconsistency (minor) is non-blocking and would be best addressed as a codebase-wide standardization effort rather than a single-PR change.
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cleveragents/cleveragents-core#1097
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