1 files changed, 99 insertions, 0 deletions
diff --git a/tests/Cepis.Tests/LookupTests.cs b/tests/Cepis.Tests/LookupTests.cs
index ad3e2bf..91f1c03 100644
--- a/tests/Cepis.Tests/LookupTests.cs
+++ b/tests/Cepis.Tests/LookupTests.cs
@@ -1,3 +1,5 @@
+using System.Globalization;
+
 namespace Cepis.Tests;
 
 /// <summary>A single lookup: the happy path, the coordinate, and the refusals.</summary>
@@ -120,6 +122,103 @@ public sealed class LookupTests : HttpTestBase
     }
 
     [Fact]
+    public async Task AMissingCepNamesTheMunicipalityItWouldBeIn()
+    {
+        Server.Respond("/25845000", Reply.Of(404, Fixtures.NotFoundWithFaixa));
+
+        var failure = await Assert.ThrowsAsync<CepNotFoundException>(
+            () => Client.LookupAsync("25845000"));
+
+        var faixa = failure.Faixa;
+        Assert.NotNull(faixa);
+        Assert.Equal("Areal", faixa.Localidade);
+        Assert.Equal("RJ", faixa.UF);
+        Assert.Equal("Rio de Janeiro", faixa.Estado);
+        Assert.Equal("Sudeste", faixa.Regiao);
+        Assert.Equal("3300225", faixa.Ibge);
+        Assert.Equal("25845001", faixa.CepIni);
+        Assert.Equal("25849899", faixa.CepFim);
+        Assert.Equal(118, faixa.Ceps);
+    }
+
+    /// <summary>
+    /// The CEP asked for, 25845000, is the DNE's own start for Areal. The range
+    /// reports what exists, so it starts one above — and holds 118 CEPs across
+    /// the ~4,900 numbers it spans, which is why the count travels with it.
+    /// </summary>
+    [Fact]
+    public async Task TheRangeIsWhatExistsAndIsSparse()
+    {
+        Server.Respond("/25845000", Reply.Of(404, Fixtures.NotFoundWithFaixa));
+
+        var failure = await Assert.ThrowsAsync<CepNotFoundException>(
+            () => Client.LookupAsync("25845000"));
+
+        var faixa = failure.Faixa;
+        Assert.NotNull(faixa);
+        Assert.NotEqual("25845000", faixa.CepIni);
+        Assert.True(faixa.Ceps < int.Parse(faixa.CepFim, CultureInfo.InvariantCulture)
+            - int.Parse(faixa.CepIni, CultureInfo.InvariantCulture));
+    }
+
+    [Fact]
+    public async Task TheMessageMentionsTheMunicipality()
+    {
+        Server.Respond("/25845000", Reply.Of(404, Fixtures.NotFoundWithFaixa));
+
+        var failure = await Assert.ThrowsAsync<CepNotFoundException>(
+            () => Client.LookupAsync("25845000"));
+
+        Assert.Contains("25845000", failure.Message, StringComparison.Ordinal);
+        Assert.Contains("Areal/RJ", failure.Message, StringComparison.Ordinal);
+    }
+
+    [Fact]
+    public async Task AMissingCepInNobodysRangeHasNoMunicipality()
+    {
+        Server.Respond("/99999999", Reply.Of(404, Fixtures.NotFound));
+
+        var failure = await Assert.ThrowsAsync<CepNotFoundException>(
+            () => Client.LookupAsync("99999999"));
+
+        Assert.Null(failure.Faixa);
+        Assert.Equal("CEP 99999999 does not exist in the DNE database", failure.Message);
+    }
+
+    [Fact]
+    public async Task ARangeOfTheWrongShapeIsDropped()
+    {
+        Server.Respond("/25845000", Reply.Of(404, Fixtures.NotFoundBrokenFaixa));
+
+        var failure = await Assert.ThrowsAsync<CepNotFoundException>(
+            () => Client.LookupAsync("25845000"));
+
+        Assert.Null(failure.Faixa);
+    }
+
+    [Fact]
+    public async Task ARangeNamingNoMunicipalityIsDropped()
+    {
+        Server.Respond("/25845000", Reply.Of(404, Fixtures.NotFoundNamelessFaixa));
+
+        var failure = await Assert.ThrowsAsync<CepNotFoundException>(
+            () => Client.LookupAsync("25845000"));
+
+        Assert.Null(failure.Faixa);
+    }
+
+    [Fact]
+    public async Task AnUnreadable404BodyIsStillJustANotFound()
+    {
+        Server.Respond("/25845000", Reply.Of(404, "<html><body>gateway</body></html>"));
+
+        var failure = await Assert.ThrowsAsync<CepNotFoundException>(
+            () => Client.LookupAsync("25845000"));
+
+        Assert.Null(failure.Faixa);
+    }
+
+    [Fact]
     public async Task A400CarriesTheApiMessage()
     {
         Server.Respond("/00000000", Reply.Of(400, Fixtures.InvalidCep));