diff --git a/test/test_multipart.rb b/test/test_multipart.rb
new file mode 100644
index 0000000..636541e
--- /dev/null
+++ b/test/test_multipart.rb
@@ -0,0 +1,82 @@
+require 'minitest/autorun'
+require 'prism'
+
+class MultipartTest < Minitest::Test
+  BOUNDARY = '----PrismTestBoundary7331'
+
+  def build_body(fields: {}, files: {})
+    parts = fields.map do |name, value|
+      "--#{BOUNDARY}\r\nContent-Disposition: form-data; name=\"#{name}\"\r\n\r\n#{value}\r\n"
+    end
+    parts += files.map do |name, spec|
+      filename, content_type, content = spec
+      "--#{BOUNDARY}\r\nContent-Disposition: form-data; name=\"#{name}\"; filename=\"#{filename}\"\r\n" \
+        "Content-Type: #{content_type}\r\n\r\n#{content}\r\n"
+    end
+    parts.join + "--#{BOUNDARY}--\r\n"
+  end
+
+  def test_multipart_detects_content_type
+    assert Prism::Multipart.multipart?('multipart/form-data; boundary=abc')
+    refute Prism::Multipart.multipart?('application/json')
+    refute Prism::Multipart.multipart?(nil)
+  end
+
+  def test_boundary_from_quoted_and_bare
+    assert_equal 'abc123', Prism::Multipart.boundary_from('multipart/form-data; boundary="abc123"')
+    assert_equal 'abc123', Prism::Multipart.boundary_from('multipart/form-data; boundary=abc123')
+    assert_nil Prism::Multipart.boundary_from('multipart/form-data')
+  end
+
+  def test_parses_plain_fields
+    body = build_body(fields: { 'title' => 'hello world', 'count' => '3' })
+    result = Prism::Multipart.parse(body, BOUNDARY)
+    assert_equal 'hello world', result['title']
+    assert_equal '3', result['count']
+  end
+
+  def test_parses_uploaded_file
+    body = build_body(
+      fields: { 'title' => 'my post' },
+      files: { 'avatar' => ['avatar.png', 'image/png', "\x89PNG\r\ndata\x00"] }
+    )
+    result = Prism::Multipart.parse(body, BOUNDARY)
+    assert_equal 'my post', result['title']
+
+    file = result['avatar']
+    assert_instance_of Prism::UploadedFile, file
+    assert_equal 'avatar.png', file.original_filename
+    assert_equal 'image/png', file.content_type
+    assert_equal "\x89PNG\r\ndata\x00".b, file.read
+    assert_equal file.size, File.size(file.path)
+  end
+
+  def test_binary_content_is_preserved_byte_for_byte
+    binary = (0..255).map(&:chr).join.b
+    body = build_body(files: { 'blob' => ['blob.bin', 'application/octet-stream', binary] })
+    result = Prism::Multipart.parse(body, BOUNDARY)
+    assert_equal binary, result['blob'].read
+  end
+
+  def test_array_field_names_collect_into_arrays
+    parts = [
+      "--#{BOUNDARY}\r\nContent-Disposition: form-data; name=\"tags[]\"\r\n\r\nruby\r\n",
+      "--#{BOUNDARY}\r\nContent-Disposition: form-data; name=\"tags[]\"\r\n\r\nweb\r\n",
+      "--#{BOUNDARY}--\r\n"
+    ]
+    result = Prism::Multipart.parse(parts.join, BOUNDARY)
+    assert_equal %w[ruby web], result['tags']
+  end
+
+  def test_empty_boundary_returns_empty_hash
+    assert_equal({}, Prism::Multipart.parse('anything', nil))
+    assert_equal({}, Prism::Multipart.parse('anything', ''))
+  end
+
+  def test_ignores_preamble_and_epilogue
+    body = "this is a preamble that must be ignored\r\n" + build_body(fields: { 'a' => '1' }) + "trailing epilogue"
+    result = Prism::Multipart.parse(body, BOUNDARY)
+    assert_equal '1', result['a']
+    assert_equal 1, result.size
+  end
+end
diff --git a/test/test_orm_attributes.rb b/test/test_orm_attributes.rb
new file mode 100644
index 0000000..0773374
--- /dev/null
+++ b/test/test_orm_attributes.rb
@@ -0,0 +1,123 @@
+require 'minitest/autorun'
+require 'prism'
+require 'tmpdir'
+require 'json'
+
+class OrmAttributesTest < Minitest::Test
+  def setup
+    @dir = Dir.mktmpdir('prism-attributes-store')
+    @store = Prism::Orm::Store.new(File.join(@dir, 'test.pstore'))
+    @store.create_table(:widgets, %w[id title featured views price published_at])
+    widget_class = Class.new(Prism::Orm::Model) do
+      table_name :widgets
+      attribute :featured, :boolean, default: false
+      attribute :views, :integer
+      attribute :price, :float
+      attribute :published_at, :datetime
+    end
+    widget_class.store = @store
+    Object.const_set(:Widget, widget_class)
+  end
+
+  def teardown
+    FileUtils.remove_entry(@dir)
+    Object.send(:remove_const, :Widget) if Object.const_defined?(:Widget)
+    Object.send(:remove_const, :Gadget) if Object.const_defined?(:Gadget)
+    Object.send(:remove_const, :SpecialGadget) if Object.const_defined?(:SpecialGadget)
+  end
+
+  def test_string_form_input_casts_to_the_declared_type_on_write
+    widget = Widget.new(featured: '1', views: '42', price: '9.5')
+    assert_equal true, widget.featured
+    assert_equal 42, widget.views
+    assert_in_delta 9.5, widget.price
+  end
+
+  def test_cast_value_is_what_actually_gets_stored_not_the_raw_string
+    widget = Widget.create!(title: 'a', featured: '1', views: '42')
+    assert_equal true, widget.to_h['featured']
+    assert_equal 42, widget.to_h['views']
+  end
+
+  def test_default_is_applied_when_the_attribute_is_omitted
+    assert_equal false, Widget.new(title: 'a').featured
+  end
+
+  def test_an_explicit_value_wins_over_the_default
+    assert_equal true, Widget.new(title: 'a', featured: 'yes').featured
+  end
+
+  def test_default_survives_a_real_save_and_reload
+    widget = Widget.create!(title: 'a')
+    reloaded = Widget.find(widget.id)
+    assert_equal false, reloaded.featured
+  end
+
+  def test_proc_default_is_evaluated_per_instance
+    Object.const_set(:Gadget, Class.new(Prism::Orm::Model) do
+      table_name :widgets
+      attribute :views, :integer, default: -> { 7 }
+    end)
+    Gadget.store = @store
+    assert_equal 7, Gadget.new(title: 'a').views
+    assert_equal 7, Gadget.new(title: 'b').views
+  end
+
+  def test_reloading_a_saved_record_returns_real_typed_values_not_strings
+    widget = Widget.create!(title: 'a', featured: '1', views: '42', price: '9.5')
+    reloaded = Widget.find(widget.id)
+    assert_equal true, reloaded.featured
+    assert_kind_of Integer, reloaded.views
+    assert_equal 42, reloaded.views
+    assert_kind_of Float, reloaded.price
+  end
+
+  def test_getter_defensively_casts_a_legacy_raw_value_never_written_through_the_setter
+    id = @store.insert(:widgets, 'title' => 'legacy', 'featured' => '1', 'views' => '3')
+    legacy = Widget.find(id)
+    assert_equal true, legacy.featured
+    assert_equal 3, legacy.views
+  end
+
+  def test_datetime_attribute_parses_an_iso8601_string
+    widget = Widget.new(title: 'a', published_at: '2026-02-01T12:00:00Z')
+    assert_kind_of Time, widget.published_at
+    assert_equal 2026, widget.published_at.year
+  end
+
+  def test_invalid_input_raises_invalid_cast_instead_of_saving_garbage
+    assert_raises(Prism::Orm::TypeCasting::InvalidCast) { Widget.new(title: 'a', views: 'not-a-number') }
+  end
+
+  def test_serializable_hash_reflects_the_cast_type_not_the_raw_string
+    widget = Widget.create!(title: 'a', featured: '1', views: '42')
+    payload = JSON.parse(widget.to_json)
+    assert_equal true, payload['featured']
+    assert_equal 42, payload['views']
+  end
+
+  # Same regression shape as Callbacks#callbacks_for / Controller#before_actions
+  # (documented in this project's history as a bug found three separate
+  # times: a class-level registry stored as a plain `@ivar ||= {}` per
+  # class, with no superclass fallback, silently drops whatever a base
+  # class declared as soon as a subclass declares its own). attribute_types/
+  # attribute_defaults use the same superclass-plus-own merge, so this
+  # proves a subclass's own `attribute` call does not erase its parent's.
+  def test_subclass_inherits_the_parent_classes_declared_attributes
+    Object.const_set(:Gadget, Class.new(Prism::Orm::Model) do
+      table_name :widgets
+      attribute :featured, :boolean, default: false
+    end)
+    Object.const_set(:SpecialGadget, Class.new(Gadget) do
+      table_name :widgets
+      attribute :views, :integer, default: 9
+    end)
+    SpecialGadget.store = @store
+
+    assert_equal %i[boolean integer].sort_by(&:to_s), [SpecialGadget.attribute_types['featured'],
+                                                         SpecialGadget.attribute_types['views']].sort_by(&:to_s)
+    special = SpecialGadget.new(title: 'a')
+    assert_equal false, special.featured, 'inherited attribute default was dropped by the subclass'
+    assert_equal 9, special.views
+  end
+end