Added basic specs to Engine.

* Still need to add specs for `.run` and the `#on()` callbacks, ideally
  using fake worker classes which yield test values instead of doing
  real recon.

spec/engine_spec.rb

@@ -0,0 +1,119 @@
+require 'spec_helper'
+require 'ronin/recon/engine'
+
+describe Ronin::Recon::Engine do
+  let(:values) do
+    [
+      Ronin::Recon::Values::IP.new('1.2.3.4'),
+      Ronin::Recon::Values::IPRange.new('1.2.3.4/24'),
+      Ronin::Recon::Values::Domain.new('example.com'),
+      Ronin::Recon::Values::Host.new('www.example.com'),
+      Ronin::Recon::Values::Wildcard.new('*.example.com')
+    ]
+  end
+
+  subject { described_class.new(values) }
+
+  describe "#initialize" do
+    it "must initialize #scope to a Ronin::Recon::Scope using the given values" do
+      expect(subject.scope).to be_kind_of(Ronin::Recon::Scope)
+      expect(subject.scope.values).to eq(values)
+    end
+
+    it "must initialize the ignored values in #scope to an empty Array" do
+      expect(subject.scope.ignore).to eq([])
+    end
+
+    it "must default #workers to Ronin::Recon::WorkerSet.default" do
+      expect(subject.workers).to eq(Ronin::Recon::WorkerSet.default)
+    end
+
+    it "must initialize #value_status to an empty Ronin::Recon::ValueStatus" do
+      expect(subject.value_status).to be_kind_of(Ronin::Recon::ValueStatus)
+      expect(subject.value_status).to be_empty
+    end
+
+    it "must initialize #graph to an empty Ronin::Recon::Graph" do
+      expect(subject.graph).to be_kind_of(Ronin::Recon::Graph)
+      expect(subject.graph).to be_empty
+    end
+
+    it "must default #max_depth to nil" do
+      expect(subject.max_depth).to be(nil)
+    end
+
+    it "must default #logger to Console.logger" do
+      expect(subject.logger).to eq(Console.logger)
+    end
+
+    context "when given the ignore: keyword argument" do
+      let(:ignore) do
+        [
+          Ronin::Recon::Values::Host.new('dev.example.com'),
+          Ronin::Recon::Values::Host.new('staging.example.com')
+        ]
+      end
+
+      subject { described_class.new(values, ignore: ignore) }
+
+      it "must initialize the #ignore of the #scope to the given ignore: keyword argument value" do
+        expect(subject.scope.ignore).to eq(ignore)
+      end
+    end
+
+    context "when given the max_depth: keyword argument" do
+      let(:max_depth) { 3 }
+
+      subject { described_class.new(values, max_depth: max_depth) }
+
+      it "must set #max_depth" do
+        expect(subject.max_depth).to eq(max_depth)
+      end
+    end
+
+    context "when given the workers: keyword argument" do
+      let(:workers) do
+        Ronin::Recon::WorkerSet.load(
+          %w[
+            dns/lookup
+            dns/mailservers
+            dns/nameservers
+            dns/subdomain_enum
+            dns/suffix_enum
+            dns/srv_enum
+          ]
+        )
+      end
+
+      subject { described_class.new(values, workers: workers) }
+
+      it "must set #workers" do
+        expect(subject.workers).to eq(workers)
+      end
+    end
+
+    context "when given the logger: keyword argument" do
+      let(:logger) { Console::Logger.new(STDOUT) }
+
+      subject { described_class.new(values, logger: logger) }
+
+      it "must set #logger" do
+        expect(subject.logger).to be(logger)
+      end
+    end
+
+    context "when given a block" do
+      it "must yield the newly created #{described_class}" do
+        expect { |b|
+          described_class.new(values,&b)
+        }.to yield_with_args(described_class)
+      end
+    end
+  end
+
+  describe "#values" do
+    it "must return #graph.nodes" do
+      expect(subject.values).to be(subject.graph.nodes)
+    end
+  end
+end