Update README with project details and setup instructions; add data directories to .gitignore

2026-08-16 17:09:16 +03:00
parent 9d09d6e97f
commit 8460921bfa
73 changed files with 6978 additions and 1 deletions
@@ -0,0 +1,132 @@
+using System.Net;
+using Microsoft.Extensions.Logging.Abstractions;
+using Microsoft.Extensions.Options;
+using TheLivingWorld.Core.Geo;
+using TheLivingWorld.Osm;
+using TheLivingWorld.Osm.Overpass;
+
+namespace TheLivingWorld.Tests;
+
+public class OverpassClientTests : IDisposable
+{
+    private static readonly GeoBounds Bounds = GeoBounds.FromCenter(new GeoPoint(31.8966010, -100.4858591), 1000);
+
+    private readonly string _cacheDirectory =
+        Path.Combine(Path.GetTempPath(), $"tlw-osm-cache-{Guid.NewGuid():n}");
+
+    [Fact]
+    public async Task Caches_the_response_and_serves_it_again_without_a_second_request()
+    {
+        var handler = new StubHandler((_, _) => Json("""{"elements":[]}"""));
+        var client = CreateClient(handler);
+
+        var first = await client.FetchAsync(Bounds, forceRefresh: false);
+        var second = await client.FetchAsync(Bounds, forceRefresh: false);
+
+        Assert.Equal(first, second);
+        Assert.Equal(1, handler.Requests);
+        Assert.Equal("""{"elements":[]}""", await File.ReadAllTextAsync(first));
+    }
+
+    [Fact]
+    public async Task Refetches_when_asked_to_refresh()
+    {
+        var handler = new StubHandler((_, _) => Json("""{"elements":[]}"""));
+        var client = CreateClient(handler);
+
+        await client.FetchAsync(Bounds, forceRefresh: false);
+        await client.FetchAsync(Bounds, forceRefresh: true);
+
+        Assert.Equal(2, handler.Requests);
+    }
+
+    [Fact]
+    public async Task Falls_back_to_the_next_mirror_after_a_retryable_failure()
+    {
+        var handler = new StubHandler((request, _) => request.RequestUri!.Host == "first.example"
+            ? new HttpResponseMessage(HttpStatusCode.TooManyRequests) { Content = new StringContent("busy") }
+            : Json("""{"elements":[]}"""));
+
+        var client = CreateClient(handler, "https://first.example/api", "https://second.example/api");
+
+        var path = await client.FetchAsync(Bounds, forceRefresh: false);
+
+        Assert.True(File.Exists(path));
+        Assert.Equal(2, handler.Requests);
+    }
+
+    [Fact]
+    public async Task Rejects_an_html_error_page_served_under_a_200()
+    {
+        // An overloaded Overpass instance answers "the server is probably too busy" as HTML with status 200.
+        var handler = new StubHandler((_, _) => new HttpResponseMessage(HttpStatusCode.OK)
+        {
+            Content = new StringContent("<html><body>too busy</body></html>", System.Text.Encoding.UTF8, "text/html"),
+        });
+
+        var client = CreateClient(handler);
+
+        var failure = await Assert.ThrowsAsync<OverpassException>(() => client.FetchAsync(Bounds, forceRefresh: false));
+
+        Assert.Contains("text/html", failure.Message);
+        Assert.False(Directory.EnumerateFiles(_cacheDirectory, "*.json").Any());
+    }
+
+    [Fact]
+    public async Task Reports_the_last_error_when_every_mirror_fails()
+    {
+        var handler = new StubHandler((_, _) => new HttpResponseMessage(HttpStatusCode.BadGateway)
+        {
+            Content = new StringContent("<p>gateway is down</p>"),
+        });
+
+        var client = CreateClient(handler);
+
+        var failure = await Assert.ThrowsAsync<OverpassException>(() => client.FetchAsync(Bounds, forceRefresh: false));
+
+        Assert.Contains("gateway is down", failure.Message);
+    }
+
+    private static HttpResponseMessage Json(string body) => new(HttpStatusCode.OK)
+    {
+        Content = new StringContent(body, System.Text.Encoding.UTF8, "application/json"),
+    };
+
+    private OverpassClient CreateClient(StubHandler handler, params string[] endpoints)
+    {
+        var options = new OsmOptions
+        {
+            CacheDirectory = _cacheDirectory,
+            MaxAttemptsPerEndpoint = 1,
+            RequestTimeoutSeconds = 5,
+        };
+
+        if (endpoints.Length > 0) options.Endpoints = endpoints;
+        else options.Endpoints = ["https://only.example/api"];
+
+        return new OverpassClient(
+            new HttpClient(handler),
+            Options.Create(options),
+            NullLogger<OverpassClient>.Instance);
+    }
+
+    public void Dispose()
+    {
+        if (Directory.Exists(_cacheDirectory)) Directory.Delete(_cacheDirectory, recursive: true);
+        GC.SuppressFinalize(this);
+    }
+
+    private sealed class StubHandler(Func<HttpRequestMessage, CancellationToken, HttpResponseMessage> respond)
+        : HttpMessageHandler
+    {
+        public int Requests { get; private set; }
+
+        protected override Task<HttpResponseMessage> SendAsync(
+            HttpRequestMessage request,
+            CancellationToken cancellationToken)
+        {
+            Requests++;
+            return Task.FromResult(respond(request, cancellationToken));
+        }
+    }
+}