unindent.rb

TEXT = <<EOF
   See, the interesting thing about this text
     is that while it seems like the first line defines an indent
       it's actually the last line which has the smallest indent

    there are also some blank lines

    both with and without extra spaces in them

    and it just goes on and on

       this text

    and starts to repeat itself
   See, the interesting thing about this text
     is that while it seems like the first line defines an indent
       it's actually the last line which has the smallest indent

    there are also some blank lines

    both with and without extra spaces in them

    and it just goes on and on

       this text

    and starts to repeat itself
   See, the interesting thing about this text
     is that while it seems like the first line defines an indent
       it's actually the last line which has the smallest indent

    there are also some blank lines

    both with and without extra spaces in them

    and it just goes on and on

       this text

    and starts to repeat itself

  The End.
EOF

EXPECTED_TEXT = <<EOF
 See, the interesting thing about this text
   is that while it seems like the first line defines an indent
     it's actually the last line which has the smallest indent

  there are also some blank lines

  both with and without extra spaces in them

  and it just goes on and on

     this text

  and starts to repeat itself
 See, the interesting thing about this text
   is that while it seems like the first line defines an indent
     it's actually the last line which has the smallest indent

  there are also some blank lines

  both with and without extra spaces in them

  and it just goes on and on

     this text

  and starts to repeat itself
 See, the interesting thing about this text
   is that while it seems like the first line defines an indent
     it's actually the last line which has the smallest indent

  there are also some blank lines

  both with and without extra spaces in them

  and it just goes on and on

     this text

  and starts to repeat itself

The End.
EOF

require "minitest/autorun"
require "minitest"
require 'minitest/pride'

class String

  def strip_heredoc
    gsub /^#{scan(/^[ \t]*\b/).min}/,''
  end

end

class TestUnindent < MiniTest::Test

  def test_strip_heredoc
    assert_equal EXPECTED_TEXT, TEXT.strip_heredoc
    assert_equal "abc", "\s\sabc".strip_heredoc # removes space indentation
    assert_equal "abc", "\tabc".strip_heredoc # removes tab indentation
    assert_equal "abc", "\t\s\sabc".strip_heredoc # removes space/tab indentation
    assert_equal ""   , "".strip_heredoc # handles empty strings
    assert_equal "abc\nabc"        , "\tabc\n\tabc"        .strip_heredoc # removes space/tab indentation
    assert_equal "abc\n\tabc"      , "\tabc\n\t\tabc"      .strip_heredoc # keeps relative indentation
    assert_equal "\nabc\n\n\tabc\n", "\n\tabc\n\n\t\tabc\n".strip_heredoc # ignores blank lines for indent calculation
  end

  def test_strip_heredoc_on_an_empty_string
    assert_equal '', ''.strip_heredoc
  end

  def test_strip_heredoc_on_a_string_with_no_lines
    assert_equal 'x', 'x'.strip_heredoc
    assert_equal 'x', '    x'.strip_heredoc
  end

  def test_strip_heredoc_on_a_heredoc_with_no_margin
    assert_equal "foo\nbar", "foo\nbar".strip_heredoc
    assert_equal "foo\n  bar", "foo\n  bar".strip_heredoc
  end

  def test_strip_heredoc_on_a_regular_indented_heredoc
    assert_equal "foo\n  bar\nbaz\n", <<-EOS.strip_heredoc
      foo
        bar
      baz
    EOS
  end

  def test_strip_heredoc_on_a_regular_indented_heredoc_with_blank_lines
    assert_equal "foo\n  bar\n\nbaz\n", <<-EOS.strip_heredoc
      foo
        bar

      baz
    EOS
  end

end

Tests from activesupport and unindent

Whoa…

👍