test_relative_path_from.rb

require 'test_helper'
class RelativePathFromTest < Minitest::Test
  def test_relative_path_from
    assert_equal FasterPath.relative_path_from("a",           "b").to_s,         "../a"
    assert_equal FasterPath.relative_path_from("a",           "b/").to_s,        "../a"
    assert_equal FasterPath.relative_path_from("a/",          "b").to_s,         "../a"
    assert_equal FasterPath.relative_path_from("a/",          "b/").to_s,        "../a"
    assert_equal FasterPath.relative_path_from("/a",          "/b").to_s,        "../a"
    assert_equal FasterPath.relative_path_from("/a",          "/b/").to_s,       "../a"
    assert_equal FasterPath.relative_path_from("/a/",         "/b").to_s,        "../a"
    assert_equal FasterPath.relative_path_from("/a/",         "/b/").to_s,       "../a"
    assert_equal FasterPath.relative_path_from("a/b",         "a/c").to_s,       "../b"
    assert_equal FasterPath.relative_path_from("../a",        "../b").to_s,      "../a"
    assert_equal FasterPath.relative_path_from("a",           ".").to_s,         "a"
    assert_equal FasterPath.relative_path_from(".",           "a").to_s,         ".."
    assert_equal FasterPath.relative_path_from(".",           ".").to_s,         "."
    assert_equal FasterPath.relative_path_from("..",          "..").to_s,        "."
    assert_equal FasterPath.relative_path_from("..",          ".").to_s,         ".."
    assert_equal FasterPath.relative_path_from("/a/b/c/d",    "/a/b").to_s,      "c/d"
    assert_equal FasterPath.relative_path_from("/a/b",        "/a/b/c/d").to_s,  "../.."
    assert_equal FasterPath.relative_path_from("/e",          "/a/b/c/d").to_s,  "../../../../e"
    assert_equal FasterPath.relative_path_from("a/b/c",       "a/d").to_s,       "../b/c"
    assert_equal FasterPath.relative_path_from("/../a",       "/b").to_s,        "../a"
    assert_equal FasterPath.relative_path_from("../a",        "b").to_s,         "../../a"
    assert_equal FasterPath.relative_path_from("/a/../../b",  "/b").to_s,        "."
    assert_equal FasterPath.relative_path_from("a/..",        "a").to_s,         ".."
    assert_equal FasterPath.relative_path_from("a/../b",      "b").to_s,         "."
    assert_equal FasterPath.relative_path_from("a",           "b/..").to_s,      "a"
    assert_equal FasterPath.relative_path_from("b/c",         "b/..").to_s,      "b/c"
    assert_raises(ArgumentError) { FasterPath.relative_path_from("/", ".")  }
    assert_raises(ArgumentError) { FasterPath.relative_path_from(".", "/")  }
    assert_raises(ArgumentError) { FasterPath.relative_path_from("a", "..") }
    assert_raises(ArgumentError) { FasterPath.relative_path_from(".", "..") }
  end

  def relative_path_str(dest, base)
    Pathname.new(dest).relative_path_from(Pathname.new(base)).to_s
  end

  def test_raises_an_error_when_the_two_paths_do_not_share_a_common_prefix
    assert_raises(ArgumentError) { relative_path_str('/usr', 'foo') }
  end

  def test_raises_an_error_when_the_base_directory_has_dot_dot
    assert_raises(ArgumentError) { relative_path_str('a', '..') }
  end

  def test_returns_a_path_relative_from_root
    assert_equal relative_path_str('/usr', '/'), 'usr'
  end

  def test_returns_1_level_up_when_both_paths_are_relative
    assert_equal relative_path_str('a', 'b'), '../a'
    assert_equal relative_path_str('a', 'b/'), '../a'
  end

  def test_returns_a_relative_path_when_both_are_absolute
    assert_equal relative_path_str('/a', '/b'), '../a'
  end

  def test_returns_a_path_relative_to_the_current_directory
    assert_equal relative_path_str('/usr/bin/ls', '/usr'), 'bin/ls'
  end

  def test_returns_a_dot_when_base_and_dest_are_the_same
    assert_equal relative_path_str('/usr', '/usr'), '.'
  end

  def test_returns_the_same_directory_with_a_non_clean_base_that_matches_the_current_dir
    assert_equal relative_path_str('/usr', '/stuff/..'), 'usr'
  end

  def test_returns_a_relative_path_with_a_non_clean_base_that_matches_a_different_dir
    assert_equal relative_path_str('/usr', '/stuff/../foo'), '../usr'
  end

  def test_returns_current_and_pattern_when_only_those_patterns_are_used
    assert_equal relative_path_str('.', '.'), '.'
    assert_equal relative_path_str('..', '..'), '.'
    assert_equal relative_path_str('..', '.'), '..'
  end
end