feat(tests): richer server-side filters + true total count for GET /tests

GET /tests caps limit at 200, so any page relying on len(results) for a
"total" count (e.g. Validated Tests) silently under-reports once there
are more matches than the page size — the 200 shown was a page cap, not
the real total.

- Adds GET /tests/count, sharing its query-building with list_tests()
  via a new _build_test_query() so the two can't drift apart.
- Adds technique_search (free-text on MITRE ID or name), attack_success,
  detection_result, and validated_from/validated_to filters, so callers
  aren't limited to state/technique_id/platform/creator.

backend/app/services/test_crud_service.py

@@ -10,8 +10,8 @@ from datetime import datetime
 from typing import Any
 
 # Import Session, joinedload from sqlalchemy.orm
-from sqlalchemy import or_
-from sqlalchemy.orm import Session, joinedload
+from sqlalchemy import func, or_
+from sqlalchemy.orm import Query, Session, joinedload
 
 # Import  from app.domain.errors
 from app.domain.errors import (
@@ -49,29 +49,27 @@ def determine_initial_classification(technique: Technique | None) -> str:
     return DataClassification.confidential.value
 
 
-# Define function list_tests
-def list_tests(
-    # Entry: db
+def _build_test_query(
     db: Session,
     *,
-    # Entry: state
     state: str | None = None,
-    # Entry: technique_id
     technique_id: uuid.UUID | None = None,
-    # Entry: platform
+    technique_search: str | None = None,
     platform: str | None = None,
-    # Entry: created_by
     created_by: uuid.UUID | None = None,
-    # Entry: pending_validation_side
     pending_validation_side: str | None = None,
-    # Entry: reviewer_id — "my reviews" queue for the red_review/blue_review gate stage
     reviewer_id: uuid.UUID | None = None,
     not_in_any_campaign: bool = False,
-    offset: int = 0,
-    # Entry: limit
-    limit: int = 50,
-) -> list[Test]:
-    """Return a paginated list of tests with optional filters."""
+    attack_success: str | None = None,
+    detection_result: str | None = None,
+    validated_from: datetime | None = None,
+    validated_to: datetime | None = None,
+) -> Query:
+    """Build the filtered Test query shared by list_tests() and count_tests().
+
+    Kept as a single source of truth so the displayed page of results and
+    the total count it's paginated against can never drift apart.
+    """
     query = db.query(Test).options(joinedload(Test.technique))
 
     # Check: state
@@ -82,6 +80,16 @@ def list_tests(
     if technique_id:
         # Assign query = query.filter(Test.technique_id == technique_id)
         query = query.filter(Test.technique_id == technique_id)
+    # Free-text technique filter (MITRE ID or name) — doesn't require the
+    # caller to already know the technique's UUID like technique_id does.
+    if technique_search:
+        pattern = f"%{escape_like(technique_search)}%"
+        query = query.join(Technique, Test.technique_id == Technique.id).filter(
+            or_(
+                Technique.mitre_id.ilike(pattern),
+                Technique.name.ilike(pattern),
+            )
+        )
     # Check: platform
     if platform:
         # Assign query = query.filter(Test.platform.ilike(f"%{escape_like(platform)}%"))
@@ -125,10 +133,102 @@ def list_tests(
         linked = db.query(CampaignTest.test_id).distinct().subquery()
         query = query.filter(~Test.id.in_(linked))
 
-    # Return query.order_by(Test.created_at.desc()).offset(offset).limit(limit)....
+    if attack_success:
+        query = query.filter(Test.attack_success == attack_success)
+    if detection_result:
+        query = query.filter(Test.detection_result == detection_result)
+
+    # Validated-date range: whichever lead validated last (mirrors the
+    # "Validated" column shown on the Validated Tests page).
+    if validated_from or validated_to:
+        validated_at = func.coalesce(Test.blue_validated_at, Test.red_validated_at)
+        if validated_from:
+            query = query.filter(validated_at >= validated_from)
+        if validated_to:
+            query = query.filter(validated_at <= validated_to)
+
+    return query
+
+
+# Define function list_tests
+def list_tests(
+    db: Session,
+    *,
+    state: str | None = None,
+    technique_id: uuid.UUID | None = None,
+    technique_search: str | None = None,
+    platform: str | None = None,
+    created_by: uuid.UUID | None = None,
+    pending_validation_side: str | None = None,
+    # Entry: reviewer_id — "my reviews" queue for the red_review/blue_review gate stage
+    reviewer_id: uuid.UUID | None = None,
+    not_in_any_campaign: bool = False,
+    attack_success: str | None = None,
+    detection_result: str | None = None,
+    validated_from: datetime | None = None,
+    validated_to: datetime | None = None,
+    offset: int = 0,
+    # Entry: limit
+    limit: int = 50,
+) -> list[Test]:
+    """Return a paginated list of tests with optional filters."""
+    query = _build_test_query(
+        db,
+        state=state,
+        technique_id=technique_id,
+        technique_search=technique_search,
+        platform=platform,
+        created_by=created_by,
+        pending_validation_side=pending_validation_side,
+        reviewer_id=reviewer_id,
+        not_in_any_campaign=not_in_any_campaign,
+        attack_success=attack_success,
+        detection_result=detection_result,
+        validated_from=validated_from,
+        validated_to=validated_to,
+    )
     return query.order_by(Test.created_at.desc()).offset(offset).limit(limit).all()
 
 
+def count_tests(
+    db: Session,
+    *,
+    state: str | None = None,
+    technique_id: uuid.UUID | None = None,
+    technique_search: str | None = None,
+    platform: str | None = None,
+    created_by: uuid.UUID | None = None,
+    pending_validation_side: str | None = None,
+    reviewer_id: uuid.UUID | None = None,
+    not_in_any_campaign: bool = False,
+    attack_success: str | None = None,
+    detection_result: str | None = None,
+    validated_from: datetime | None = None,
+    validated_to: datetime | None = None,
+) -> int:
+    """Return the total count of tests matching the same filters as list_tests().
+
+    Lets the frontend show a true total even when the page size caps the
+    number of rows actually returned (e.g. GET /tests's limit<=200).
+    """
+    query = _build_test_query(
+        db,
+        state=state,
+        technique_id=technique_id,
+        technique_search=technique_search,
+        platform=platform,
+        created_by=created_by,
+        pending_validation_side=pending_validation_side,
+        reviewer_id=reviewer_id,
+        not_in_any_campaign=not_in_any_campaign,
+        attack_success=attack_success,
+        detection_result=detection_result,
+        validated_from=validated_from,
+        validated_to=validated_to,
+    )
+    return query.count()
+
+
 # Define function create_test
 def create_test(
     # Entry: db