diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index d5f2f6a..781927a 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -9,9 +9,11 @@ on:
       - synchronize
 jobs:
   ci:
-    runs-on: ubuntu-latest
+    runs-on: ${{ matrix.runner }}
     strategy:
       matrix:
+        # Ruby 3.1 is unavailable on Ubuntu 26.04 (ubuntu-latest).
+        runner: [ubuntu-24.04, ubuntu-24.04-arm]
         ruby:
           - "3.1"
           - "3.2"
diff --git a/test/unit/test_transloadit.rb b/test/unit/test_transloadit.rb
index 4a07589..64335c6 100644
--- a/test/unit/test_transloadit.rb
+++ b/test/unit/test_transloadit.rb
@@ -62,7 +62,7 @@
       _(step).must_be_kind_of Transloadit::Step
       _(step.name).must_equal "resize"
       _(step.robot).must_equal "/image/resize"
-      _(step.options).must_equal width: 320
+      _(step.options).must_equal({width: 320})
     end
 
     it "must create assembly api instances" do
diff --git a/test/unit/transloadit/test_api.rb b/test/unit/transloadit/test_api.rb
index 3196e3a..11ebfb8 100644
--- a/test/unit/transloadit/test_api.rb
+++ b/test/unit/transloadit/test_api.rb
@@ -27,10 +27,10 @@
     end
 
     it "must remember the options passed" do
-      _(api.options).must_equal(
+      _(api.options).must_equal({
         foo: foo,
         bar: bar
-      )
+      })
     end
 
     it "must inspect like a hash" do
@@ -38,11 +38,11 @@
     end
 
     it "must produce Transloadit-compatible hash output" do
-      _(api.to_hash).must_equal(
+      _(api.to_hash).must_equal({
         auth: transloadit.to_hash,
         foo: foo,
         bar: bar
-      )
+      })
     end
 
     it "must produce Transloadit-compatible JSON output" do
diff --git a/test/unit/transloadit/test_assembly.rb b/test/unit/transloadit/test_assembly.rb
index b845cd8..0ea449a 100644
--- a/test/unit/transloadit/test_assembly.rb
+++ b/test/unit/transloadit/test_assembly.rb
@@ -30,15 +30,15 @@
 
     it "must not wrap a hash step" do
       @assembly.options[:steps] = {foo: 1}
-      _(@assembly.steps).must_equal foo: 1
+      _(@assembly.steps).must_equal({foo: 1})
     end
 
     it "must produce Transloadit-compatible hash output" do
-      _(@assembly.to_hash).must_equal(
+      _(@assembly.to_hash).must_equal({
         auth: @transloadit.to_hash,
         steps: @assembly.steps,
         redirect_url: @redirect
-      )
+      })
     end
 
     it "must submit files for upload" do
@@ -170,7 +170,8 @@
             response = @assembly.create! open("lib/transloadit/version.rb")
             _(response["ok"]).must_equal "ASSEMBLY_COMPLETED"
           }
-          _(warning).must_equal "Rate limit reached. Waiting for 0 seconds before retrying.\n"
+          # Dependencies may emit deprecation warnings on their first use.
+          _(warning.lines.count("Rate limit reached. Waiting for 0 seconds before retrying.\n")).must_equal 1
         end
       end
 
diff --git a/test/unit/transloadit/test_response.rb b/test/unit/transloadit/test_response.rb
index 227cafd..7866e53 100644
--- a/test/unit/transloadit/test_response.rb
+++ b/test/unit/transloadit/test_response.rb
@@ -24,7 +24,7 @@
 
     _(returned).must_be_same_as response
     _(response["ok"]).must_equal "ASSEMBLY_COMPLETED"
-    _(response.headers).must_equal x_request_id: "new-request"
+    _(response.headers).must_equal({x_request_id: "new-request"})
     _(response.code).must_equal 200
     _(response.status).must_equal 200
   end
diff --git a/test/unit/transloadit/test_step.rb b/test/unit/transloadit/test_step.rb
index d4c2206..54b0df2 100644
--- a/test/unit/transloadit/test_step.rb
+++ b/test/unit/transloadit/test_step.rb
@@ -29,11 +29,11 @@
     end
 
     it "must remember the parameters" do
-      _(@step.options).must_equal(
+      _(@step.options).must_equal({
         key: @key,
         secret: @secret,
         bucket: @bucket
-      )
+      })
     end
 
     it "must inspect like a hash" do
@@ -41,14 +41,14 @@
     end
 
     it "must produce Transloadit-compatible hash output" do
-      _(@step.to_hash).must_equal(
+      _(@step.to_hash).must_equal({
         @step.name => {
           robot: @robot,
           key: @key,
           secret: @secret,
           bucket: @bucket
         }
-      )
+      })
     end
 
     it "must produce Transloadit-compatible JSON output" do
diff --git a/test/unit/transloadit/test_transport_compatibility.rb b/test/unit/transloadit/test_transport_compatibility.rb
index 57e6dbc..81f27be 100644
--- a/test/unit/transloadit/test_transport_compatibility.rb
+++ b/test/unit/transloadit/test_transport_compatibility.rb
@@ -23,7 +23,7 @@
     _(response["ok"]).must_equal "ASSEMBLY_COMPLETED"
     assert_requested(:get, /\A#{Regexp.escape(endpoint)}/) do |request|
       query = Addressable::URI.parse(request.uri.to_s).query_values
-      _(MultiJson.load(query.fetch("params"))).must_equal "wait" => true
+      _(MultiJson.load(query.fetch("params"))).must_equal({"wait" => true})
       _(query.fetch("signature")).must_match(/\Asha384:[0-9a-f]{96}\z/)
       _(request.headers.fetch("Transloadit-Client")).must_equal "ruby-sdk:#{Transloadit::VERSION}"
     end
@@ -38,7 +38,7 @@
 
     assert_requested(:post, endpoint) do |request|
       form = URI.decode_www_form(request.body).to_h
-      _(MultiJson.load(form.fetch("params"))).must_equal "template_id" => "template-id"
+      _(MultiJson.load(form.fetch("params"))).must_equal({"template_id" => "template-id"})
       _(form.fetch("signature")).must_match(/\Asha384:[0-9a-f]{96}\z/)
       _(request.headers.fetch("Content-Type")).must_match(/\Aapplication\/x-www-form-urlencoded/)
     end
@@ -53,7 +53,7 @@
 
     assert_requested(:put, endpoint) do |request|
       form = URI.decode_www_form(request.body).to_h
-      _(MultiJson.load(form.fetch("params"))).must_equal "name" => "Updated"
+      _(MultiJson.load(form.fetch("params"))).must_equal({"name" => "Updated"})
       _(form.fetch("signature")).must_match(/\Asha384:[0-9a-f]{96}\z/)
     end
   end
@@ -67,7 +67,7 @@
 
     assert_requested(:delete, endpoint) do |request|
       form = URI.decode_www_form(request.body).to_h
-      _(MultiJson.load(form.fetch("params"))).must_equal "reason" => "cleanup"
+      _(MultiJson.load(form.fetch("params"))).must_equal({"reason" => "cleanup"})
       _(form.fetch("signature")).must_match(/\Asha384:[0-9a-f]{96}\z/)
     end
   end
@@ -86,7 +86,7 @@
     _(response).wont_be_kind_of Faraday::Response
     _(response.code).must_equal 422
     _(response.status).must_equal 422
-    _(response.headers).must_equal retry_after: "5", x_request_id: "request-id"
+    _(response.headers).must_equal({retry_after: "5", x_request_id: "request-id"})
     _(response["error"]).must_equal "ASSEMBLY_NOT_FOUND"
   end