fix: guard against falsy-value traps in psycopg2, chromadb, weaviate mocks

[koushik1359]

Problem

Three test mocks mishandled falsy values (0, False, 0.0), causing tests
to pass against mocks while failing against real services in production.

psycopg2 — bool subclasses int in Python, so isinstance(False, int)
returns True. SQL WHERE params like isDeleted=False were being matched
as LIMIT values in _handle_semantic_search and _extract_limit.

chromadb — if limit and ... treated limit=0 as falsy, returning
all rows instead of zero rows when get(limit=0) was called.

weaviate — Sort key distance if distance else 1.0 collapsed 0.0
(exact match, the best possible cosine distance) to 1.0, ranking
perfect matches last instead of first.

Fix

• psycopg2: added not isinstance(p, bool) guard at both int-detection sites
• chromadb: replaced if limit with if limit is not None
• weaviate: replaced if distance with if distance is not None

Resolves #748

Summary by CodeRabbit

• Tests
  • Improved test mock accuracy for edge cases involving zero and false parameter values, ensuring proper handling in parameter validation and result sorting scenarios.

[github-actions]

No description provided.

[coderabbitai]

📝 Walkthrough

Walkthrough

This PR corrects three Python truthiness and isinstance bugs across test mocks for ChromaDB, PostgreSQL, and Weaviate. The fixes replace falsy-based conditionals and type checks with explicit None guards and boolean exclusions to ensure zero-valued parameters and distances are treated as valid.

Changes

Test Mock Truthiness and isinstance Fixes

Layer / File(s)	Summary
ChromaDB Limit Parameter nodes/test/mocks/chromadb/__init__.py	MockCollection.get() limit check now uses limit is not None instead of truthiness, so limit=0 correctly enforces zero-row results.
PostgreSQL Parameter Type Checking nodes/test/mocks/psycopg2/__init__.py	Semantic search and limit extraction now require isinstance(p, int) and not isinstance(p, bool) to prevent booleans from being interpreted as numeric limits.
Weaviate Vector Distance Sorting nodes/test/mocks/weaviate/__init__.py	MockQuery.near_vector sort key now checks metadata.distance is not None instead of truthiness, so zero-distance exact matches are not collapsed into fallback scores.

Estimated code review effort

🎯 2 (Simple) | ⏱️ ~8 minutes

Possibly related issues

• #747: Issue requesting these identical fixes across all three test mocks (chromadb, psycopg2, weaviate) to correct truthiness/isinstance traps in parameter handling and sorting logic.

Poem

🐰 Hop, hop, the mocks now see—
Zero's valid, booleans flee!
No more truthiness in the way,
Distances sort right today. ✨

🚥 Pre-merge checks | ✅ 5

✅ Passed checks (5 passed)

Check name	Status	Explanation
Description Check	✅ Passed	Check skipped - CodeRabbit’s high-level summary is enabled.
Title check	✅ Passed	The title accurately and concisely summarizes the main change: fixing falsy-value handling bugs in three test mocks.
Linked Issues check	✅ Passed	All three objectives from issue #748 are fully met: psycopg2 mock guards against booleans, chromadb mock treats limit=0 correctly, and weaviate mock preserves 0.0 distances.
Out of Scope Changes check	✅ Passed	All changes are scoped to the three specified mock files with minimal, targeted fixes; no unrelated modifications or scope creep detected.
Docstring Coverage	✅ Passed	Docstring coverage is 100.00% which is sufficient. The required threshold is 80.00%.

_{✏️ Tip: You can configure your own custom pre-merge checks in the settings.}

✨ Finishing Touches

🧪 Generate unit tests (beta)

• Create PR with unit tests

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Caution

Some comments are outside the diff and can’t be posted inline due to platform limitations.

⚠️ Outside diff range comments (2)

nodes/test/mocks/psycopg2/__init__.py (1)

155-158: ⚠️ Potential issue | 🟡 Minor | ⚡ Quick win

Same falsy-value trap remains in _handle_select_query — if limit: should be if limit is not None:.

_extract_limit returns Optional[int], so a non-boolean integer 0 in the params list would be returned as a valid limit but then silently skipped here because if limit: is if 0: → False. This is the identical class of bug being fixed across the other three mocks in this PR, and it lives in the same file.

🐛 Proposed fix

-        if limit:
+        if limit is not None:
             results = results[:limit]

🤖 Prompt for AI Agents

Verify each finding against current code. Fix only still-valid issues, skip the
rest with a brief reason, keep changes minimal, and validate.

In `@nodes/test/mocks/psycopg2/__init__.py` around lines 155 - 158, In
_handle_select_query, the LIMIT check uses a falsy test that skips valid 0
limits; change the conditional that currently reads "if limit:" to explicitly
check for None (i.e., "if limit is not None:") so a returned integer 0 from
_extract_limit is applied; locate the _handle_select_query function and the
_extract_limit helper and update the limit application accordingly.

nodes/test/mocks/chromadb/__init__.py (1)

174-186: ⚠️ Potential issue | 🟡 Minor | ⚡ Quick win

limit=0 still yields 1 result — check must precede the append.

The item is appended at line 174 before the guard at line 185. When limit=0, the check evaluates 0 is not None and len(results['ids']) >= 0 → True on the very first iteration — but only after the first item has already been added. The PR's stated goal of "return 0 rows for limit=0" is not achieved.

🐛 Proposed fix — move the limit guard before the append

+            # Apply limit (guard before append so limit=0 correctly returns empty)
+            if limit is not None and len(results['ids']) >= limit:
+                break
+
             results['ids'].append(id)
             if 'metadatas' in include:
                 results['metadatas'].append(self._serialize_metadata(metadata))
@@ -182,9 +182,6 @@
             if 'embeddings' in include:
                 results['embeddings'].append(data.get('embedding'))

             count += 1

-            # Apply limit
-            if limit is not None and len(results['ids']) >= limit:
-                break

🤖 Prompt for AI Agents

Verify each finding against current code. Fix only still-valid issues, skip the
rest with a brief reason, keep changes minimal, and validate.

In `@nodes/test/mocks/chromadb/__init__.py` around lines 174 - 186, The loop
appends an item to results['ids'] (and optionally
metadatas/documents/embeddings) before checking the limit, so limit=0 still
returns one row; move the limit guard that checks "if limit is not None and
len(results['ids']) >= limit" to the top of the iteration (before appending) so
no items are added when the current length already meets the limit; update the
block around results['ids'].append(id) /
results['metadatas'].append(self._serialize_metadata(metadata)) /
results['documents'].append(document) /
results['embeddings'].append(data.get('embedding')) to perform the limit check
first and then append, keeping the existing count increment and break behavior.

🤖 Prompt for all review comments with AI agents

Verify each finding against current code. Fix only still-valid issues, skip the
rest with a brief reason, keep changes minimal, and validate.

Outside diff comments:
In `@nodes/test/mocks/chromadb/__init__.py`:
- Around line 174-186: The loop appends an item to results['ids'] (and
optionally metadatas/documents/embeddings) before checking the limit, so limit=0
still returns one row; move the limit guard that checks "if limit is not None
and len(results['ids']) >= limit" to the top of the iteration (before appending)
so no items are added when the current length already meets the limit; update
the block around results['ids'].append(id) /
results['metadatas'].append(self._serialize_metadata(metadata)) /
results['documents'].append(document) /
results['embeddings'].append(data.get('embedding')) to perform the limit check
first and then append, keeping the existing count increment and break behavior.

In `@nodes/test/mocks/psycopg2/__init__.py`:
- Around line 155-158: In _handle_select_query, the LIMIT check uses a falsy
test that skips valid 0 limits; change the conditional that currently reads "if
limit:" to explicitly check for None (i.e., "if limit is not None:") so a
returned integer 0 from _extract_limit is applied; locate the
_handle_select_query function and the _extract_limit helper and update the limit
application accordingly.

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ℹ️ Review info

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📥 Commits

Reviewing files that changed from the base of the PR and between 5c88da5 and 5f831bb.

📒 Files selected for processing (3)

• nodes/test/mocks/chromadb/__init__.py
• nodes/test/mocks/psycopg2/__init__.py
• nodes/test/mocks/weaviate/__init__.py