1 files changed, 109 insertions, 0 deletions
diff --git a/spec/lib/csv_builder_spec.rb b/spec/lib/csv_builder_spec.rb
new file mode 100644
index 00000000000..0d5e2b81b16
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+++ b/spec/lib/csv_builder_spec.rb
@@ -0,0 +1,109 @@
+# frozen_string_literal: true
+
+require 'spec_helper'
+
+describe CsvBuilder do
+  let(:object) { double(question: :answer) }
+  let(:fake_relation) { FakeRelation.new([object]) }
+  let(:subject) { described_class.new(fake_relation, 'Q & A' => :question, 'Reversed' => -> (o) { o.question.to_s.reverse }) }
+  let(:csv_data) { subject.render }
+
+  before do
+    stub_const('FakeRelation', Array)
+
+    FakeRelation.class_eval do
+      def find_each(&block)
+        each(&block)
+      end
+    end
+  end
+
+  it 'generates a csv' do
+    expect(csv_data.scan(/(,|\n)/).join).to include ",\n,"
+  end
+
+  it 'uses a temporary file to reduce memory allocation' do
+    expect(CSV).to receive(:new).with(instance_of(Tempfile)).and_call_original
+
+    subject.render
+  end
+
+  it 'counts the number of rows' do
+    subject.render
+
+    expect(subject.rows_written).to eq 1
+  end
+
+  describe 'rows_expected' do
+    it 'uses rows_written if CSV rendered successfully' do
+      subject.render
+
+      expect(fake_relation).not_to receive(:count)
+      expect(subject.rows_expected).to eq 1
+    end
+
+    it 'falls back to calling .count before rendering begins' do
+      expect(subject.rows_expected).to eq 1
+    end
+  end
+
+  describe 'truncation' do
+    let(:big_object) { double(question: 'Long' * 1024) }
+    let(:row_size) { big_object.question.length * 2 }
+    let(:fake_relation) { FakeRelation.new([big_object, big_object, big_object]) }
+
+    it 'occurs after given number of bytes' do
+      expect(subject.render(row_size * 2).length).to be_between(row_size * 2, row_size * 3)
+      expect(subject).to be_truncated
+      expect(subject.rows_written).to eq 2
+    end
+
+    it 'is ignored by default' do
+      expect(subject.render.length).to be > row_size * 3
+      expect(subject.rows_written).to eq 3
+    end
+
+    it 'causes rows_expected to fall back to .count' do
+      subject.render(0)
+
+      expect(fake_relation).to receive(:count).and_call_original
+      expect(subject.rows_expected).to eq 3
+    end
+  end
+
+  it 'avoids loading all data in a single query' do
+    expect(fake_relation).to receive(:find_each)
+
+    subject.render
+  end
+
+  it 'uses hash keys as headers' do
+    expect(csv_data).to start_with 'Q & A'
+  end
+
+  it 'gets data by calling method provided as hash value' do
+    expect(csv_data).to include 'answer'
+  end
+
+  it 'allows lamdas to look up more complicated data' do
+    expect(csv_data).to include 'rewsna'
+  end
+
+  describe 'excel sanitization' do
+    let(:dangerous_title) { double(title: "=cmd|' /C calc'!A0 title", description: "*safe_desc") }
+    let(:dangerous_desc) { double(title: "*safe_title", description: "=cmd|' /C calc'!A0 desc") }
+    let(:fake_relation) { FakeRelation.new([dangerous_title, dangerous_desc]) }
+    let(:subject) { described_class.new(fake_relation, 'Title' => 'title', 'Description' => 'description') }
+    let(:csv_data) { subject.render }
+
+    it 'sanitizes dangerous characters at the beginning of a column' do
+      expect(csv_data).to include "'=cmd|' /C calc'!A0 title"
+      expect(csv_data).to include "'=cmd|' /C calc'!A0 desc"
+    end
+
+    it 'does not sanitize safe symbols at the beginning of a column' do
+      expect(csv_data).not_to include "'*safe_desc"
+      expect(csv_data).not_to include "'*safe_title"
+    end
+  end
+end