Add test for Line::Bot::Request#content_type

Author: mizoR

spec/fixtures/line/bot/preview.jpg

@@ -0,0 +1,45 @@
+require 'spec_helper'
+
+describe Line::Bot::Request do
+  describe '#content_type' do
+    subject { request.content_type }
+
+    context 'content type is not specified' do
+      let(:request) { described_class.new }
+
+      it { is_expected.to eq 'application/json; charset=UTF-8' }
+    end
+
+    context 'content type is specified' do
+      let(:request) do
+        described_class.new do |config|
+          config.content_type = 'application/x-www-form-urlencoded'
+        end
+      end
+
+      it { is_expected.to eq 'application/x-www-form-urlencoded' }
+    end
+
+    context 'jpeg file is assigned' do
+      let(:request) do
+        described_class.new do |config|
+          config.file = File.open('spec/fixtures/line/bot/preview.jpg')
+        end
+      end
+
+      it { is_expected.to eq 'image/jpeg' }
+    end
+
+    context 'unsupported file is assigned' do
+      let(:request) do
+        described_class.new do |config|
+          config.file = File.open('spec/fixtures/line/bot/video.mp4')
+        end
+      end
+
+      it do
+        expect { subject }.to raise_error(ArgumentError)
+      end
+    end
+  end
+end