Catch repeated EF Core queries in tests

QueryGuard counts database queries, groups repeated SQL, and checks query limits. Use it to catch possible N+1 problems before merging your code.

Works with EF Core 8 and 10. See provider support.

Install

For ASP.NET Core integration tests:

dotnet add package QueryGuard.AspNetCore.Testing

Available on NuGet. For services and background jobs, use QueryGuard.Testing.

Check one request

Use your application's Program and AppDbContext types:

using Microsoft.AspNetCore.Mvc.Testing;
using QueryGuard;
using QueryGuard.AspNetCore.Testing;
using QueryGuard.Testing;

using var factory = new WebApplicationFactory<Program>();
await using var guard = factory.TrackQueries<Program, AppDbContext>(
    "GET /api/companies",
    QueryGuardPolicy.Create("companies").WithMaxOccurrencesPerFingerprint(5));

var response = await guard.Client.GetAsync("/api/companies");
response.EnsureSuccessStatusCode();

QueryGuardAssert.Passes(await guard.CompleteAsync());

The test fails if the same query runs more than five times. Always send requests through guard.Client.

Read a failure

QueryGuard FAILED: GET /api/companies (policy 'companies')
  51 read queries in 2 distinct queries

  [FAIL] max-occurrences-per-fingerprint: QG-FP-FDB5F469 executed 50 times; the budget is 5.
          SQL: SELECT COUNT(*) FROM "Departments" AS "d" WHERE "d"."CompanyId" = ?
          origin: samples/QueryGuard.SampleApi/Program.cs:line 89

The report shows the repeated query, its count, your limit, and where it ran. Repeated SQL can be intentional. Review each finding before changing the code.

Next steps

Task Guide
Measure requests, services, or jobs Testing
Set query limits and capture options Configuration
Compare query counts with a saved result Baselines
Fix setup problems Troubleshooting
Allow intentional repetition When a finding is wrong
Understand sessions and query IDs How it works
Browse types and methods API reference

Limits and privacy

QueryGuard captures relational EF Core commands. It does not capture Dapper or raw ADO.NET calls, prove an N+1 defect, or fix queries for you.

By default, reports exclude parameter values and redact SQL string and number values. Connection strings are not captured. See privacy settings.

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