# encoding: utf-8

require 'spec_helper'

describe Mutant::Differ, '#diff' do
  let(:object) { described_class.new(old, new) }

  subject { object.diff }

  context 'when there is a diff at begin of hunk' do
    let(:old) { %w(foo bar) }
    let(:new) { %w(baz bar) }

    let(:expectation) do
      strip_indent(<<-STR)
        @@ -1,3 +1,3 @@
        -foo
        +baz
         bar
      STR
    end

    it { should eql(expectation) }

    it_should_behave_like 'an idempotent method'
  end

  context 'when there is a diff NOT at begin of hunk' do
    let(:old) { %w(foo bar)     }
    let(:new) { %w(foo baz bar) }

    let(:expectation) do
      strip_indent(<<-STR)
        @@ -1,3 +1,4 @@
         foo
        +baz
         bar
      STR
    end

    it { should eql(expectation) }

    it_should_behave_like 'an idempotent method'
  end

  context 'when the diff has a long context at begin' do
    let(:old) { %w(foo bar baz boz a b c)       }
    let(:new) { %w(foo bar baz boz a b c other) }

    let(:expectation) do
      strip_indent(<<-STR)
        @@ -1,8 +1,9 @@
         foo
         bar
         baz
         boz
         a
         b
         c
        +other
      STR
    end

    it { should eql(expectation) }

    it_should_behave_like 'an idempotent method'
  end

  context 'when the diff has a long context at end, deleting' do
    let(:old) { %w(other foo bar baz boz a b c) }
    let(:new) { %w(foo bar baz boz a b c)       }

    let(:expectation) do
      strip_indent(<<-STR)
        @@ -1,9 +1,8 @@
        -other
         foo
         bar
         baz
         boz
         a
         b
         c
      STR
    end

    it { should eql(expectation) }

    it_should_behave_like 'an idempotent method'
  end

  context 'when the diff has a long context at end, inserting' do
    let(:old) { %w(foo bar baz boz a b c)       }
    let(:new) { %w(other foo bar baz boz a b c) }

    let(:expectation) do
      strip_indent(<<-STR)
        @@ -1,8 +1,9 @@
        +other
         foo
         bar
         baz
         boz
         a
         b
         c
      STR
    end

    it { should eql(expectation) }

    it_should_behave_like 'an idempotent method'
  end

  context 'when there is no diff' do
    let(:old) { '' }
    let(:new) { '' }

    it { should be(nil) }

    it_should_behave_like 'an idempotent method'
  end
end