Add GET /reports/{id} endpoint using Spec Driven Development

app/main.py

@@ -7,7 +7,7 @@
 from fastapi import FastAPI, HTTPException, Query
 
 from app.models import ReportListResponse, ReportPublic, ReportStatus
-from app.reports import query
+from app.reports import query, get_report_by_id
 
 app = FastAPI(title="SDD Workshop — Reports API", version="0.1.0")
 
@@ -51,3 +51,17 @@ def list_reports(
         offset=offset,
         limit=limit,
     )
+
+@app.get("/reports/{id}", response_model=ReportPublic)
+def get_report(id: int) -> ReportPublic:
+    """Return one report by ID."""
+
+    report = get_report_by_id(id)
+
+    if report is None:
+        raise HTTPException(
+            status_code=404,
+            detail="Report not found",
+        )
+
+    return ReportPublic.from_internal(report)

app/reports.py

@@ -39,3 +39,14 @@ def query(
         rows = (r for r in rows if r.created_at <= date_to)
 
     return sorted(rows, key=lambda r: getattr(r, sort), reverse=descending)
+
+def get_report_by_id(report_id: int) -> Report | None:
+    """Return one report by ID or None if missing."""
+
+    rows = all_reports()
+
+    for report in rows:
+        if report.id == report_id:
+            return report
+
+    return None

openspec/changes/get-report-by-id/proposal.md

@@ -0,0 +1,24 @@
+# Proposal
+
+## Motivation
+
+Clients currently fetch all reports and filter client-side to find one record.
+
+Direct lookup reduces payload and improves usability.
+
+## Changes
+
+ADD:
+
+GET /reports/{id}
+
+Behavior:
+
+- Return report if found
+- Return 404 if missing
+
+## Non-goals
+
+- Existing routes unchanged
+- No authentication changes
+- No changes to PublicReport model

openspec/changes/get-report-by-id/specs/reports/spec.md

@@ -0,0 +1,29 @@
+# Spec Delta
+
+## ADD
+
+### Endpoint
+
+GET /reports/{id}
+
+### Parameters
+
+id:
+- type: integer
+- required: true
+
+### Responses
+
+200:
+Return existing public report model
+
+404:
+{
+  "detail": "Report not found"
+}
+
+### Constraints
+
+- Existing `/reports` endpoint behavior remains unchanged
+- Existing pagination behavior remains unchanged
+- Reuse existing response model

openspec/changes/get-report-by-id/tasks.md

@@ -0,0 +1,7 @@
+# Tasks
+
+- [x] Add helper function in app/reports.py
+- [x] Add route in app/main.py
+- [x] Add success test
+- [x] Add 404 test
+- [x] Verify all tests pass

openspec/project.md

@@ -0,0 +1,18 @@
+# Project Context
+
+## Tech Stack
+- Python
+- FastAPI
+- Pydantic
+- In-memory dataset
+
+## Conventions
+- All routes return JSON
+- Existing routes must remain unchanged
+- Public models never expose internal fields
+- Existing API behavior preserved
+
+## Constraints
+- Preserve `/reports` contract
+- Preserve pagination behavior
+- No breaking changes to existing endpoints

tests/test_reports.py

@@ -0,0 +1,38 @@
+from fastapi.testclient import TestClient
+
+from app.main import app
+
+
+client = TestClient(app)
+
+
+def test_get_report_found():
+
+    reports = client.get("/reports").json()["items"]
+
+    existing_id = reports[0]["id"]
+
+    response = client.get(f"/reports/{existing_id}")
+
+    assert response.status_code == 200
+
+    data = response.json()
+
+    assert data["id"] == existing_id
+
+    assert "internal_id" not in data
+
+    assert "owner_email" not in data
+
+
+def test_get_report_missing():
+
+    reports = client.get("/reports").json()["items"]
+
+    missing_id = max(r["id"] for r in reports) + 1
+
+    response = client.get(f"/reports/{missing_id}")
+
+    assert response.status_code == 404
+
+    assert response.json()["detail"] == "Report not found"