3 files changed, 114 insertions, 0 deletions
diff --git a/test/cepis/lookup_test.exs b/test/cepis/lookup_test.exs
index b68ecbe..39d9d31 100644
--- a/test/cepis/lookup_test.exs
+++ b/test/cepis/lookup_test.exs
@@ -87,6 +87,80 @@ defmodule Cepis.LookupTest do
     assert Exception.message(error) =~ "99999999"
   end
 
+  test "a not-found names the municipality the CEP would belong to", %{
+    server: server,
+    client: client
+  } do
+    body = not_found_fixture(%{"faixa" => faixa_fixture()})
+    FakeServer.respond(server, "/25845000", {404, json(body), []})
+
+    assert {:error, %Cepis.NotFoundError{cep: "25845000", faixa: faixa} = error} =
+             Cepis.lookup("25845-000", client)
+
+    assert faixa.localidade == "Areal"
+    assert faixa.uf == "RJ"
+    assert faixa.estado == "Rio de Janeiro"
+    assert faixa.regiao == "Sudeste"
+    assert faixa.ibge == "3300225"
+    assert faixa.cep_ini == "25845001"
+    assert faixa.cep_fim == "25849899"
+    assert faixa.ceps == 118
+
+    assert Exception.message(error) =~ "Areal/RJ"
+    assert Exception.message(error) =~ "25845000 does not exist"
+  end
+
+  test "a not-found in a band no municipality owns has no faixa", %{
+    server: server,
+    client: client
+  } do
+    FakeServer.respond(server, "/99999999", {404, json(not_found_fixture()), []})
+
+    assert {:error, %Cepis.NotFoundError{faixa: nil} = error} = Cepis.lookup("99999999", client)
+    assert Exception.message(error) == "CEP 99999999 does not exist in the DNE database"
+  end
+
+  test "a malformed faixa does not become a parse failure", %{server: server, client: client} do
+    bodies = [
+      not_found_fixture(%{"faixa" => %{}}),
+      not_found_fixture(%{"faixa" => %{"uf" => "RJ"}}),
+      not_found_fixture(%{"faixa" => %{"localidade" => ""}}),
+      not_found_fixture(%{"faixa" => "Areal"}),
+      # the API omits the field rather than nulling it, but a null must not
+      # cost the caller the error either
+      not_found_fixture(%{"faixa" => :null})
+    ]
+
+    for {body, index} <- Enum.with_index(bodies) do
+      path = "/2584500#{index}"
+      FakeServer.respond(server, path, {404, json(body), []})
+
+      assert {:error, %Cepis.NotFoundError{faixa: nil}} =
+               Cepis.lookup(String.trim_leading(path, "/"), client)
+    end
+  end
+
+  test "a 404 body that is not JSON is still a clean not-found", %{
+    server: server,
+    client: client
+  } do
+    FakeServer.respond(server, "/99999999", {404, "<html>gateway</html>", []})
+
+    assert {:error, %Cepis.NotFoundError{cep: "99999999", faixa: nil}} =
+             Cepis.lookup("99999999", client)
+  end
+
+  test "a faixa keeps whatever the API sends, even partially", %{server: server, client: client} do
+    body = not_found_fixture(%{"faixa" => %{"localidade" => "Areal", "ceps" => "118"}})
+    FakeServer.respond(server, "/25845000", {404, json(body), []})
+
+    assert {:error, %Cepis.NotFoundError{faixa: faixa}} = Cepis.lookup("25845000", client)
+    assert faixa.localidade == "Areal"
+    assert faixa.ceps == 118
+    assert faixa.cep_ini == ""
+    assert Cepis.Faixa.density(faixa) == 0.0
+  end
+
   test "a 404 is never retried", %{server: server, client: client} do
     FakeServer.respond(server, "/99999999", {404, json(%{"erro" => "cep_nao_encontrado"}), []})
 
diff --git a/test/cepis_test.exs b/test/cepis_test.exs
index a6bedb1..df9256a 100644
--- a/test/cepis_test.exs
+++ b/test/cepis_test.exs
@@ -67,6 +67,26 @@ defmodule CepisTest do
     end
   end
 
+  describe "Cepis.Faixa.density/1" do
+    test "measures how sparse the range really is" do
+      faixa = %Cepis.Faixa{cep_ini: "25845001", cep_fim: "25849899", ceps: 118}
+
+      assert_in_delta Cepis.Faixa.density(faixa), 0.024, 0.001
+      assert Cepis.Faixa.density(faixa) < 1.0
+    end
+
+    test "is 0.0 when the bounds are not two readable numbers" do
+      assert Cepis.Faixa.density(%Cepis.Faixa{}) == 0.0
+      assert Cepis.Faixa.density(%Cepis.Faixa{cep_ini: "25845001", ceps: 118}) == 0.0
+      assert Cepis.Faixa.density(%Cepis.Faixa{cep_ini: "x", cep_fim: "y", ceps: 118}) == 0.0
+    end
+
+    test "is 0.0 when the bounds are inverted" do
+      faixa = %Cepis.Faixa{cep_ini: "25849899", cep_fim: "25845001", ceps: 118}
+      assert Cepis.Faixa.density(faixa) == 0.0
+    end
+  end
+
   describe "Cepis.Address.formatted_cep/1" do
     test "adds the mask" do
       assert Cepis.Address.formatted_cep(%Cepis.Address{cep: "01001000"}) == "01001-000"
diff --git a/test/support/server_case.ex b/test/support/server_case.ex
index a64bb05..8af08cb 100644
--- a/test/support/server_case.ex
+++ b/test/support/server_case.ex
@@ -44,8 +44,28 @@ defmodule Cepis.ServerCase do
 
   @csv_header "cep,logradouro,complemento,unidade,bairro,localidade,uf,estado,regiao,ibge,gia,ddd,siafi"
 
+  @faixa %{
+    "localidade" => "Areal",
+    "uf" => "RJ",
+    "estado" => "Rio de Janeiro",
+    "regiao" => "Sudeste",
+    "ibge" => "3300225",
+    "cep_ini" => "25845001",
+    "cep_fim" => "25849899",
+    "ceps" => 118
+  }
+
   def address_fixture(extra \\ %{}), do: Map.merge(@address, extra)
 
+  def faixa_fixture(extra \\ %{}), do: Map.merge(@faixa, extra)
+
+  def not_found_fixture(extra \\ %{}) do
+    Map.merge(
+      %{"erro" => "cep_nao_encontrado", "mensagem" => "CEP não existe na base do DNE"},
+      extra
+    )
+  end
+
   def json(term), do: IO.iodata_to_binary(:json.encode(term))
 
   def csv(rows), do: Enum.join([@csv_header | rows], "\n") <> "\n"