add ensure absent for file line

4 files changed, 44 insertions, 7 deletions

diff --git a/Rakefile b/Rakefile
index bca9c85..f87faac 100644
--- a/Rakefile
+++ b/Rakefile
@@ -1,5 +1,6 @@
 require 'rake/testtask'
 
+# TODO: How to run only a specific test?
 Rake::TestTask.new do |t|
   t.libs << 'test'
   t.test_files = FileList['test/**/*_test.rb']
diff --git a/TODO.md b/TODO.md
index 9304832..120fec9 100644
--- a/TODO.md
+++ b/TODO.md
@@ -1,6 +1,5 @@
 # TODO
 
-* Backup of files when changed
 * Recursively install a directory
 * Support for file deletion
 * Support for file modes (owner, chmod)
diff --git a/lib/dslkeywords/file.rb b/lib/dslkeywords/file.rb
index dbcc612..020a97f 100644
--- a/lib/dslkeywords/file.rb
+++ b/lib/dslkeywords/file.rb
@@ -22,9 +22,12 @@ module RCM
   class File < Resource
     include FileBackup
 
+    class UnsupportedOperation < StandardError; end
+
     def initialize(file_path)
       super(file_path)
       @file_path = file_path
+      @is = :installed
     end
 
     def content(text = nil)
@@ -36,7 +39,7 @@ module RCM
     def create_parent_directory = @create_parent = true
     def from_sourcefile = @from_sourcefile = true
     def from_template = @from_template = true
-    def ensure_line(line) = @ensure_line = line
+    def line(line) = @ensure_line = line
 
     def path(file_path = nil)
       return @file_path if file_path.nil?
@@ -44,17 +47,23 @@ module RCM
       @file_path = file_path
     end
 
+    def is(what)
+      @is = what.to_sym
+      raise UnsupportedOperation, "Unsupported operation #{@is}" unless %i[present absent].include?(@is)
+    end
+
     def evaluate!
       return unless super
       return evaluate_ensure_line! unless @ensure_line.nil?
 
-      write_content!(real_content)
+      write!(real_content)
     end
 
     private
 
     def evaluate_ensure_line!
-      return write_content!(@ensure_line) unless ::File.file?(@file_path)
+      return evaluate_ensure_line_absent! if @is == :absent
+      return write!(@ensure_line) unless ::File.file?(@file_path)
       return if ::File.readlines(@file_path, chomp: true).include?(@ensure_line)
 
       ::File.open(@file_path, 'a') do |fd|
@@ -62,7 +71,15 @@ module RCM
       end
     end
 
-    def write_content!(text)
+    def evaluate_ensure_line_absent!
+      return unless ::File.file?(@file_path)
+
+      write!(::File.readlines(@file_path, chomp: true).reject do |line|
+               line == @ensure_line
+             end.join("\n"))
+    end
+
+    def write!(text)
       info "Managing file #{@file_path}"
 
       create_parent_directory!
diff --git a/test/lib/dslkeywords/file_test.rb b/test/lib/dslkeywords/file_test.rb
index de1615a..60b659e 100644
--- a/test/lib/dslkeywords/file_test.rb
+++ b/test/lib/dslkeywords/file_test.rb
@@ -50,12 +50,32 @@ class RCMFileTest < Minitest::Test
     assert_equal 'One plus two is 3!', File.read(FILE_PATH)
   end
 
-  def test_ensure_line
+  def test_line
     File.write(FILE_PATH, "Hey there\n")
-    configure_from_scratch { file(FILE_PATH) { ensure_line 'Whats up?' } }
+    configure_from_scratch { file(FILE_PATH) { line 'Whats up?' } }
     assert_equal "Hey there\nWhats up?\n", File.read(FILE_PATH)
   end
 
+  def test_line_absent
+    File.write(FILE_PATH, "Hey there\nWhats up?")
+    configure_from_scratch do
+      file(FILE_PATH) do
+        line 'Whats up?'
+        is :absent
+      end
+    end
+    assert_equal 'Hey there', File.read(FILE_PATH)
+
+    File.write(FILE_PATH, "Hey there\nWhats up?")
+    configure_from_scratch do
+      file(FILE_PATH) do
+        line 'Hey there'
+        is :absent
+      end
+    end
+    assert_equal 'Whats up?', File.read(FILE_PATH)
+  end
+
   def test_create_parent_directory
     file_path = "#{DIR_PATH}/foo/bar/baz/foo.txt"
     configure_from_scratch do