Added mailboxes as local data sources (#1022)

app/Tests/Tools/Databases/IndexStoreDataSourceStateTests.cs

@@ -0,0 +1,50 @@
+using AIStudio.Tools;
+using AIStudio.Tools.Databases.IndexStore;
+
+using Microsoft.EntityFrameworkCore;
+
+namespace AIStudio.Tests.Tools.Databases;
+
+/// <summary>
+/// Checks the row the index keeps for a data source as a whole.
+/// </summary>
+/// <remarks>
+/// Whether a data source has an index at all is read from this row alone. A data source can end up
+/// with no document indexed but with documents known to fail, e.g., a folder of scans without a
+/// text layer, and those failures hang on this row.
+/// </remarks>
+[TestFixture]
+public sealed class IndexStoreDataSourceStateTests
+{
+    private const string DATA_SOURCE_ID = "6f1d6a4e-6a5e-4c62-9a4f-0f2d2c8b7a11";
+
+    [Test]
+    public async Task ADataSourceWithOnlyFailedDocumentsKeepsItsRowUntilItIsDeleted()
+    {
+        var token = CancellationToken.None;
+        await using var store = await TemporaryIndexStore.CreateAsync();
+
+        await store.Client.UpsertDataSourceAsync(DATA_SOURCE_ID, "LOCAL_DIRECTORY", "b0a4c4d2-1f3e-4f0a-8c9d-5a6b7c8d9e01", "signature", "source-hash", 3, token);
+        await store.Client.UpsertPermanentFailureAsync(
+            DATA_SOURCE_ID,
+            new PermanentIndexingFailure("d06c4351-2e57-2941-aa4c-d7a814bfa418", "/tmp/test-data/scan.pdf", "fingerprint", FileExtractionErrorCode.NO_CONTENT, "No text could be read.", DateTimeOffset.UtcNow),
+            token);
+
+        Assert.That(
+            await store.Client.GetDataSourceStateAsync(DATA_SOURCE_ID, token),
+            Is.Not.Null,
+            "No document made it into the index, but the failures did. Without the row nothing would remember them, and every run would read the scans again.");
+
+        await store.Client.DeleteDataSourceAsync(DATA_SOURCE_ID, token);
+
+        var stateAfterDeletion = await store.Client.GetDataSourceStateAsync(DATA_SOURCE_ID, token);
+        await using var context = store.CreateContext();
+        var failuresAfterDeletion = await context.PermanentIndexingFailures.CountAsync(token);
+
+        Assert.Multiple(() =>
+        {
+            Assert.That(stateAfterDeletion, Is.Null);
+            Assert.That(failuresAfterDeletion, Is.Zero, "The failures go with the data source.");
+        });
+    }
+}