Replace Mox with Patch

test/consumer_offset_fetcher_test.exs

@@ -0,0 +1,47 @@
+defmodule KafkaexLagExporter.ConsumerOffsetFetcher.Test do
+  use ExUnit.Case, async: true
+  use Patch
+
+  @test_consumer_group_name1 "test_consumer_1"
+  @test_consumer_group_name2 "test_consumer_2"
+  @test_lags [{0, 23}, {1, 42}, {2, 666}]
+
+  setup do
+    patch(
+      KafkaexLagExporter.KafkaUtils,
+      :get_consumer_group_names,
+      fn _ -> [@test_consumer_group_name1, @test_consumer_group_name2] end
+    )
+
+    patch(KafkaexLagExporter.KafkaUtils, :lag, fn _, _, _ -> @test_lags end)
+
+    patch(
+      KafkaexLagExporter.KafkaUtils,
+      :topic_names_for_consumer_groups,
+      fn _, _, _ ->
+        [
+          {@test_consumer_group_name1, ["test_topic_1", "test_topic_2"]},
+          {@test_consumer_group_name2, ["test_topic_3"]}
+        ]
+      end
+    )
+
+    :ok
+  end
+
+  test "should return the calculated lags" do
+    test_endpoint = {"test endpoint", 666}
+
+    %{sum: sum, lags: lags} = KafkaexLagExporter.ConsumerOffsetFetcher.get(test_endpoint)
+
+    assert sum == [
+             {@test_consumer_group_name1, 1462},
+             {@test_consumer_group_name2, 731}
+           ]
+
+    assert lags == [
+             {@test_consumer_group_name1, @test_lags ++ @test_lags},
+             {@test_consumer_group_name2, @test_lags}
+           ]
+  end
+end