diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index 316e654..f9cd896 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -37,12 +37,21 @@ jobs:
         run: mix deps.get && mix deps.unlock --check-unused
         if: ${{ matrix.lint }}
 
+      - name: Check formatting
+        run: mix format --check-formatted
+        if: ${{ matrix.lint }}
+
       - name: Compile with --warnings-as-errors
         run: mix compile --warnings-as-errors
         if: ${{ matrix.lint }}
 
+      - name: Run tests
+        run: mix test --warnings-as-errors
+        if: ${{ matrix.lint }}
+
       - name: Run tests
         run: mix test
+        if: ${{ !matrix.lint }}
 
   test_older_elixir:
     runs-on: ubuntu-22.04
diff --git a/test/http_client_test.exs b/test/http_client_test.exs
index d640f15..88476b0 100644
--- a/test/http_client_test.exs
+++ b/test/http_client_test.exs
@@ -1,6 +1,8 @@
 defmodule Tzdata.HTTPClientTest do
   use ExUnit.Case, async: true
 
+  import ExUnit.CaptureLog
+
   @url "https://data.iana.org/time-zones/tzdata-latest.tar.gz"
 
   test "Httpc client can HEAD the IANA tzdata URL over verified HTTPS, when it can verify certificates" do
@@ -17,7 +19,19 @@ defmodule Tzdata.HTTPClientTest do
   end
 
   test "Hackney client can HEAD the IANA tzdata URL over verified HTTPS" do
-    assert {:ok, {200, headers}} = Tzdata.HTTPClient.Hackney.head(@url, [], [])
+    # Hackney support is deprecated: call it via `apply/3` so the compiler's
+    # static `@deprecated` check doesn't fire, and capture the runtime
+    # deprecation log it emits, since triggering both here is expected.
+    # `capture_log/2` (rather than `with_log/1`, added in Elixir 1.13) keeps
+    # this working on the oldest Elixir version this library supports.
+    log =
+      capture_log(fn ->
+        send(self(), {:head_result, apply(Tzdata.HTTPClient.Hackney, :head, [@url, [], []])})
+      end)
+
+    assert_received {:head_result, result}
+    assert {:ok, {200, headers}} = result
     assert Enum.any?(headers, fn {k, _v} -> String.downcase(k) == "content-length" end)
+    assert log =~ "Hackney"
   end
 end