diff --git a/regression_tests/bug_0_14_1_test.rb b/regression_tests/bug_0_14_1_test.rb
new file mode 100644
index 00000000..3587a881
--- /dev/null
+++ b/regression_tests/bug_0_14_1_test.rb
@@ -0,0 +1,32 @@
+# frozen_string_literal: true
+
+require "test_helper"
+require "support/http_helpers"
+
+class Bug_0_14_1_Test < Minitest::Test
+  include HTTPHelpers
+
+  def test_multipart_can_have_arbitrary_conntent_type
+    uri = "https://#{httpbin}/post"
+
+    response = HTTPX.plugin(:multipart)
+                    .post(uri, form: {
+                            image: {
+                              content_type: "image/png",
+                              body: File.new(fixture_file_path),
+                            },
+                          })
+    verify_status(response, 200)
+    body = json_body(response)
+    verify_header(body["headers"], "Content-Type", "multipart/form-data")
+    # can't really test the filename, but if it's in the files field,
+    # then it was a file upload
+    verify_uploaded_image(body, "image", "image/png")
+  end
+
+  private
+
+  def origin(orig = httpbin)
+    "http://#{orig}"
+  end
+end
diff --git a/regression_tests/bug_0_14_2_test.rb b/regression_tests/bug_0_14_2_test.rb
new file mode 100644
index 00000000..83788f14
--- /dev/null
+++ b/regression_tests/bug_0_14_2_test.rb
@@ -0,0 +1,32 @@
+# frozen_string_literal: true
+
+require "test_helper"
+require "support/http_helpers"
+
+class Bug_0_14_2_Test < Minitest::Test
+  include HTTPHelpers
+
+  def test_multipart_can_have_arbitrary_filename
+    uri = "https://#{httpbin}/post"
+
+    response = HTTPX.plugin(:multipart)
+                    .post(uri, form: {
+                            image: {
+                              filename: "weird-al-jankovic",
+                              body: File.new(fixture_file_path),
+                            },
+                          })
+    verify_status(response, 200)
+    body = json_body(response)
+    verify_header(body["headers"], "Content-Type", "multipart/form-data")
+    # can't really test the filename, but if it's in the files field,
+    # then it was a file upload
+    verify_uploaded_image(body, "image", "image/jpeg")
+  end
+
+  private
+
+  def origin(orig = httpbin)
+    "http://#{orig}"
+  end
+end
diff --git a/test/support/assertion_helpers.rb b/test/support/assertion_helpers.rb
index fe0ca6e6..491eede8 100644
--- a/test/support/assertion_helpers.rb
+++ b/test/support/assertion_helpers.rb
@@ -64,4 +64,31 @@ module ResponseHelpers
       raise "unexpected expectation (#{expectation})"
     end
   end
+
+  # test files
+
+  def verify_uploaded_image(body, key, mime_type, skip_verify_data: false)
+    assert body.key?("files"), "there were no files uploaded"
+    assert body["files"].key?(key), "there is no image in the file"
+    # checking mime-type is a bit leaky, as httpbin displays the base64-encoded data
+    return if skip_verify_data
+
+    assert body["files"][key].start_with?("data:#{mime_type}"), "data was wrongly encoded (#{body["files"][key][0..64]})"
+  end
+
+  def fixture
+    File.read(fixture_file_path, encoding: Encoding::BINARY)
+  end
+
+  def fixture_name
+    File.basename(fixture_file_path)
+  end
+
+  def fixture_file_name
+    "image.jpg"
+  end
+
+  def fixture_file_path
+    File.join("test", "support", "fixtures", fixture_file_name)
+  end
 end
diff --git a/test/support/requests/plugins/multipart.rb b/test/support/requests/plugins/multipart.rb
index 30631543..1c14e780 100644
--- a/test/support/requests/plugins/multipart.rb
+++ b/test/support/requests/plugins/multipart.rb
@@ -219,31 +219,6 @@ module Requests
         assert check_error[retries_response], "expected #{retries_response} to be an error response"
         assert retries_session.calls == 1, "expect request to be retried 1 time (was #{retries_session.calls})"
       end
-
-      def fixture
-        File.read(fixture_file_path, encoding: Encoding::BINARY)
-      end
-
-      def fixture_name
-        File.basename(fixture_file_path)
-      end
-
-      def fixture_file_name
-        "image.jpg"
-      end
-
-      def fixture_file_path
-        File.join("test", "support", "fixtures", fixture_file_name)
-      end
-
-      def verify_uploaded_image(body, key, mime_type, skip_verify_data: false)
-        assert body.key?("files"), "there were no files uploaded"
-        assert body["files"].key?(key), "there is no image in the file"
-        # checking mime-type is a bit leaky, as httpbin displays the base64-encoded data
-        return if skip_verify_data
-
-        assert body["files"][key].start_with?("data:#{mime_type}"), "data was wrongly encoded (#{body["files"][key][0..64]})"
-      end
     end
   end
 end