feat(web): add FastAPI backend with scan, plot, and benchmark endpoints

tests/test_web.py

@@ -0,0 +1,84 @@
+"""Tests for the web backend."""
+
+import pytest
+from fastapi.testclient import TestClient
+from pathlib import Path
+from unittest.mock import AsyncMock, patch
+
+from disk_checker.web.server import app
+
+
+@pytest.fixture
+def client():
+    """Create test client."""
+    return TestClient(app)
+
+
+@pytest.fixture
+def sample_csv_content():
+    """Sample CSV content for testing."""
+    return """nsec,read_clat_ns_count,read_clat_ns_cumulative,read_clat_ns_percentile
+19791872,1,1,0.00016775708773695687
+22413312,4,5,0.0008387854386847844
+22675456,9,14,0.0023485992283173965
+"""
+
+
+@pytest.fixture
+def sample_csv_path(tmp_path, sample_csv_content):
+    """Create sample CSV file."""
+    path = tmp_path / "test.csv"
+    path.write_text(sample_csv_content)
+    return path
+
+
+def test_health_check(client):
+    """Test health check endpoint."""
+    response = client.get("/health")
+    assert response.status_code == 200
+    assert response.json()["status"] == "ok"
+
+
+def test_scan_csv(client, sample_csv_path):
+    """Test CSV scan endpoint."""
+    with open(sample_csv_path, "rb") as f:
+        response = client.post("/api/v1/scan", files={"file": f})
+    assert response.status_code == 200
+    data = response.json()
+    assert "metrics" in data
+    assert len(data["metrics"]) > 0
+
+
+def test_plot_endpoint(client, sample_csv_path):
+    """Test plot generation endpoint."""
+    with open(sample_csv_path, "rb") as f:
+        response = client.post("/api/v1/plot", files={"file": f})
+    assert response.status_code == 200
+    assert response.headers["content-type"] == "image/png"
+
+
+def test_plot_with_options(client, sample_csv_path):
+    """Test plot generation with options."""
+    with open(sample_csv_path, "rb") as f:
+        response = client.post(
+            "/api/v1/plot",
+            files={"file": f},
+            data={
+                "metric": "read_clat",
+                "unit": "ms",
+                "log_x": "true",
+                "cdf": "true",
+            },
+        )
+    assert response.status_code == 200
+
+
+def test_invalid_metric(client, sample_csv_path):
+    """Test invalid metric returns error."""
+    with open(sample_csv_path, "rb") as f:
+        response = client.post(
+            "/api/v1/plot",
+            files={"file": f},
+            data={"metric": "invalid_metric"},
+        )
+    assert response.status_code == 400