chore(storage): Fix sample storage_generate_signed_post_policy_v4

refs: #8402
pr: #8406

google-cloud-storage/samples/acceptance/files_test.rb

@@ -474,24 +474,65 @@ def mock_cipher.random_key
 
     assert bucket.file remote_file_name
   end
+  describe "post object" do
+    require "net/http"
+    require "uri"
+    let(:uri) { URI.parse Google::Cloud::Storage::GOOGLEAPIS_URL }
+    let(:data) { File.expand_path "../../acceptance/data/logo.jpg", __dir__ }
+
+    it "generate_signed_post_policy_v4" do
+      refute bucket.file remote_file_name
+      post_object = nil
+      out, _err = capture_io do
+        post_object = generate_signed_post_policy_v4 bucket_name: bucket.name,
+                                                     file_name:   remote_file_name
+      end
 
-  it "generate_signed_post_policy_v4" do
-    refute bucket.file remote_file_name
+      assert_includes out, "<form action='https://storage.googleapis.com/#{bucket.name}/'"
+      assert_includes out, "<input name='key' value='#{remote_file_name}'"
+      assert_includes out, "<input name='x-goog-signature'"
+      assert_includes out, "<input name='x-goog-date'"
+      assert_includes out, "<input name='x-goog-credential'"
+      assert_includes out, "<input name='x-goog-algorithm' value='GOOG4-RSA-SHA256'"
+      assert_includes out, "<input name='policy'"
+      assert_includes out, "<input name='x-goog-meta-test' value='data'"
+      assert_includes out, "<input type='file' name='file'/>"
+      assert_includes out, "<input type='submit' value='Upload File'/>"
+
+      assert post_object
+      expected_keys = [
+        "key",
+        "policy",
+        "x-goog-algorithm",
+        "x-goog-credential",
+        "x-goog-date",
+        "x-goog-meta-test",
+        "x-goog-signature"
+      ]
+      assert_equal expected_keys, post_object.fields.keys.sort
+
+      form_data = [["file", File.open(data)]]
+
+      post_object.fields.each do |key, value|
+        form_data.push [key, value]
+      end
 
-    out, _err = capture_io do
-      generate_signed_post_policy_v4 bucket_name: bucket.name,
-                                     file_name:   remote_file_name
-    end
-
-    assert_includes out, "<form action='https://storage.googleapis.com/#{bucket.name}/'"
-    assert_includes out, "<input name='key' value='#{remote_file_name}'"
-    assert_includes out, "<input name='x-goog-signature'"
-    assert_includes out, "<input name='x-goog-date'"
-    assert_includes out, "<input name='x-goog-credential'"
-    assert_includes out, "<input name='x-goog-algorithm' value='GOOG4-RSA-SHA256'"
-    assert_includes out, "<input name='policy'"
-    assert_includes out, "<input name='x-goog-meta-test' value='data'"
-    assert_includes out, "<input type='file' name='file'/>"
+      http = Net::HTTP.new uri.host, uri.port
+      http.use_ssl = true
+      request = Net::HTTP::Post.new post_object.url
+      request.set_form form_data, "multipart/form-data"
+
+      response = http.request request
+
+      _(response.code).must_equal "204"
+      file = bucket.file post_object.fields["key"]
+      _(file).wont_be :nil?
+      Tempfile.open ["google-cloud-logo", ".jpg"] do |tmpfile|
+        tmpfile.binmode
+        downloaded = file.download tmpfile
+        _(File.read(downloaded.path, mode: "rb")).must_equal File.read(data, mode: "rb")
+      end
+    end
   end
 
   it "set_event_based_hold" do

google-cloud-storage/samples/storage_generate_signed_post_policy_v4.rb

@@ -27,18 +27,20 @@ def generate_signed_post_policy_v4 bucket_name:, file_name:
   bucket = storage.bucket bucket_name
   post_object = bucket.generate_signed_post_policy_v4 file_name,
                                                       expires: 600,
-                                                      fields:  { "x-goog-meta-test": "data" }
+                                                      fields:  { "x-goog-meta-test" => "data" }
 
   html_form = "<form action='#{post_object.url}' method='POST' enctype='multipart/form-data'>\n"
   post_object.fields.each do |name, value|
     html_form += "  <input name='#{name}' value='#{value}' type='hidden'/>\n"
   end
   html_form += "  <input type='file' name='file'/><br />\n"
-  html_form += "  <input type='submit' value='Upload File' name='submit'/><br />\n"
+  html_form += "  <input type='submit' value='Upload File'/><br />\n"
   html_form += "</form>\n"
 
   puts "You can use the following form to upload an object to bucket #{bucket_name} for the next 10 minutes:\n"
   puts html_form
+
+  post_object
 end
 # [END storage_generate_signed_post_policy_v4]