test: add CLI spec

spec/cli_spec.rb

@@ -0,0 +1,43 @@
+# frozen_string_literal: true
+
+RSpec.describe RogueOne::CLI do
+  def capture(stream)
+    begin
+      stream = stream.to_s
+      eval "$#{stream} = StringIO.new"
+      yield
+      result = eval("$#{stream}").string
+    ensure
+      eval("$#{stream} = #{stream.upcase}")
+    end
+    result
+  end
+
+  describe "#report" do
+    let(:mock) { double("detector") }
+    let(:report) { { "verdict" => "benign one", "landing_pages" => [] } }
+
+    before do
+      allow(mock).to receive(:report).and_return(report)
+      allow(RogueOne::Detector).to receive(:new).and_return(mock)
+    end
+
+    it do
+      stdout = capture(:stdout) { described_class.start %w(report 1.1.1.1) }
+      json = JSON.parse(stdout)
+      expect(json).to eq(report)
+    end
+
+    context "with ping error" do
+      before do
+        allow(RogueOne::Ping).to receive(:pong?).and_raise("error")
+      end
+
+      it do
+        stdout = capture(:stdout) { described_class.start %w(report 1.1.1.1) }
+        json = JSON.parse(stdout)
+        expect(json).to eq("error" => "error")
+      end
+    end
+  end
+end