Implement `file_contains' condition keyword

spec/producer/core/condition/dsl_spec.rb

@@ -6,7 +6,7 @@ module Producer::Core
     let(:env)     { double 'env' }
     subject(:dsl) { Condition::DSL.new(env, &block) }
 
-    %w[has_dir has_env has_file].each do |test|
+    %w[file_contains has_dir has_env has_file].each do |test|
       it "has `#{test}' test defined" do
         expect(dsl).to respond_to test.to_sym
       end

spec/producer/core/tests/file_contains_spec.rb

@@ -0,0 +1,44 @@
+require 'spec_helper'
+
+module Producer::Core
+  describe Tests::FileContains do
+    let(:env)       { Env.new }
+    let(:filepath)  { 'some_file' }
+    let(:content)   { 'some_content' }
+    subject(:test)  { Tests::FileContains.new(env, filepath, content) }
+
+    it 'is a kind of test' do
+      expect(test).to be_a Test
+    end
+
+    describe '#verify' do
+      let(:fs) { double 'fs' }
+
+      before { allow(test).to receive(:fs) { fs } }
+
+      context 'when file contains the content' do
+        before { allow(fs).to receive(:file_read).with(filepath) { "foo#{content}bar" } }
+
+        it 'returns true' do
+          expect(test.verify).to be true
+        end
+      end
+
+      context 'when file does not contain the content' do
+        before { allow(fs).to receive(:file_read).with(filepath) { 'foo bar' } }
+
+        it 'returns false' do
+          expect(test.verify).to be false
+        end
+      end
+
+      context 'when file does not exist' do
+        before { allow(fs).to receive(:file_read).with(filepath) { nil } }
+
+        it 'returns false' do
+          expect(test.verify).to be false
+        end
+      end
+    end
+  end
+end