Add tests for benchmarks, diff, trends, and flamegraph endpoints

Covers benchmark name listing with filters, diff table with delta
calculations, single and batch trend queries, and flamegraph retrieval.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

Author: ambv

backend/tests/test_benchmarks.py

@@ -0,0 +1,140 @@
+"""Tests for the benchmarks API endpoints."""
+
+import pytest
+
+
+@pytest.mark.asyncio
+async def test_all_benchmark_names_empty(client):
+    response = await client.get("/api/benchmarks")
+    assert response.status_code == 200
+    assert response.json() == []
+
+
+@pytest.mark.asyncio
+async def test_all_benchmark_names(client, sample_benchmark_result):
+    response = await client.get("/api/benchmarks")
+    assert response.status_code == 200
+    data = response.json()
+    assert "json_dumps" in data
+
+
+@pytest.mark.asyncio
+async def test_filtered_benchmark_names(client, sample_benchmark_result):
+    response = await client.get(
+        "/api/benchmark-names",
+        params={
+            "environment_id": "linux-x86_64",
+            "binary_id": "default",
+            "python_major": 3,
+            "python_minor": 14,
+        },
+    )
+    assert response.status_code == 200
+    data = response.json()
+    assert "json_dumps" in data
+
+
+@pytest.mark.asyncio
+async def test_filtered_benchmark_names_no_match(client, sample_benchmark_result):
+    response = await client.get(
+        "/api/benchmark-names",
+        params={
+            "environment_id": "linux-x86_64",
+            "binary_id": "default",
+            "python_major": 3,
+            "python_minor": 99,
+        },
+    )
+    assert response.status_code == 200
+    assert response.json() == []
+
+
+@pytest.mark.asyncio
+async def test_diff_table(client, sample_benchmark_result):
+    response = await client.get(
+        "/api/diff",
+        params={
+            "commit_sha": "a" * 40,
+            "binary_id": "default",
+            "environment_id": "linux-x86_64",
+        },
+    )
+    assert response.status_code == 200
+    data = response.json()
+    assert len(data) == 1
+    row = data[0]
+    assert row["benchmark_name"] == "json_dumps"
+    assert row["curr_metric_value"] == 1_000_000
+    assert row["metric_key"] == "high_watermark_bytes"
+    assert row["has_flamegraph"] is True
+
+
+@pytest.mark.asyncio
+async def test_diff_table_commit_not_found(client):
+    response = await client.get(
+        "/api/diff",
+        params={
+            "commit_sha": "f" * 40,
+            "binary_id": "default",
+            "environment_id": "linux-x86_64",
+        },
+    )
+    assert response.status_code == 404
+
+
+@pytest.mark.asyncio
+async def test_trends(client, sample_benchmark_result):
+    response = await client.get(
+        "/api/trends",
+        params={
+            "benchmark_name": "json_dumps",
+            "binary_id": "default",
+            "environment_id": "linux-x86_64",
+            "python_major": 3,
+            "python_minor": 14,
+        },
+    )
+    assert response.status_code == 200
+    data = response.json()
+    assert len(data) == 1
+    assert data[0]["sha"] == "a" * 40
+    assert data[0]["high_watermark_bytes"] == 1_000_000
+
+
+@pytest.mark.asyncio
+async def test_trends_batch(client, sample_benchmark_result):
+    response = await client.post(
+        "/api/trends-batch",
+        json={
+            "trend_queries": [
+                {
+                    "benchmark_name": "json_dumps",
+                    "binary_id": "default",
+                    "environment_id": "linux-x86_64",
+                    "python_major": 3,
+                    "python_minor": 14,
+                    "limit": 50,
+                }
+            ]
+        },
+    )
+    assert response.status_code == 200
+    data = response.json()
+    assert "results" in data
+    assert len(data["results"]) == 1
+
+
+@pytest.mark.asyncio
+async def test_flamegraph(client, sample_benchmark_result):
+    result_id = sample_benchmark_result.id
+    response = await client.get(f"/api/flamegraph/{result_id}")
+    assert response.status_code == 200
+    data = response.json()
+    assert data["flamegraph_html"] == "<html>flamegraph</html>"
+    assert data["benchmark_name"] == "json_dumps"
+
+
+@pytest.mark.asyncio
+async def test_flamegraph_not_found(client):
+    response = await client.get("/api/flamegraph/nonexistent")
+    assert response.status_code == 404