MiniTest::Assertions

MiniTest Assertions. All assertion methods accept a msg which is printed if the assertion fails.

Constants

UNDEFINED
WINDOZE

Public Class Methods

diff() click to toggle source

Returns the diff command to use in diff. Tries to intelligently figure out what diff to use.

# File lib/minitest/unit.rb, line 69
def self.diff
  @diff = if WINDOZE
            "diff.exe -u"
          else
            if system("gdiff", __FILE__, __FILE__)
              "gdiff -u" # solaris and kin suck
            elsif system("diff", __FILE__, __FILE__)
              "diff -u"
            else
              nil
            end
          end unless defined? @diff

  @diff
end
diff=(o) click to toggle source

Set the diff command to use in diff.

# File lib/minitest/unit.rb, line 88
def self.diff= o
  @diff = o
end

Public Instance Methods

assert(test, msg = nil) click to toggle source

Fails unless test is a true value.

# File lib/minitest/unit.rb, line 174
def assert test, msg = nil
  msg ||= "Failed assertion, no message given."
  self._assertions += 1
  unless test then
    msg = msg.call if Proc === msg
    raise MiniTest::Assertion, msg
  end
  true
end
assert_block(msg = nil) click to toggle source

Fails unless the block returns a true value.

# File lib/minitest/unit.rb, line 187
def assert_block msg = nil
  msg = message(msg) { "Expected block to return true value" }
  assert yield, msg
end
assert_empty(obj, msg = nil) click to toggle source

Fails unless obj is empty.

# File lib/minitest/unit.rb, line 195
def assert_empty obj, msg = nil
  msg = message(msg) { "Expected #{mu_pp(obj)} to be empty" }
  assert_respond_to obj, :empty?
  assert obj.empty?, msg
end
assert_equal(exp, act, msg = nil) click to toggle source

Fails unless exp == act printing the difference between the two, if possible.

If there is no visible difference but the assertion fails, you should suspect that your #== is buggy, or your inspect output is missing crucial details.

For floats use assert_in_delta.

See also: MiniTest::Assertions.diff

# File lib/minitest/unit.rb, line 213
def assert_equal exp, act, msg = nil
  msg = message(msg, "") { diff exp, act }
  assert(exp == act, msg)
end
assert_in_delta(exp, act, delta = 0.001, msg = nil) click to toggle source

For comparing Floats. Fails unless exp and act are within delta of each other.

assert_in_delta Math::PI, (22.0 / 7.0), 0.01
# File lib/minitest/unit.rb, line 224
def assert_in_delta exp, act, delta = 0.001, msg = nil
  n = (exp - act).abs
  msg = message(msg) { "Expected #{exp} - #{act} (#{n}) to be < #{delta}" }
  assert delta >= n, msg
end
assert_in_epsilon(a, b, epsilon = 0.001, msg = nil) click to toggle source

For comparing Floats. Fails unless exp and act have a relative error less than epsilon.

# File lib/minitest/unit.rb, line 234
def assert_in_epsilon a, b, epsilon = 0.001, msg = nil
  assert_in_delta a, b, [a, b].min * epsilon, msg
end
assert_includes(collection, obj, msg = nil) click to toggle source

Fails unless collection includes obj.

# File lib/minitest/unit.rb, line 241
def assert_includes collection, obj, msg = nil
  msg = message(msg) {
    "Expected #{mu_pp(collection)} to include #{mu_pp(obj)}"
  }
  assert_respond_to collection, :include?
  assert collection.include?(obj), msg
end
assert_instance_of(cls, obj, msg = nil) click to toggle source

Fails unless obj is an instance of cls.

# File lib/minitest/unit.rb, line 252
def assert_instance_of cls, obj, msg = nil
  msg = message(msg) {
    "Expected #{mu_pp(obj)} to be an instance of #{cls}, not #{obj.class}"
  }

  assert obj.instance_of?(cls), msg
end
assert_kind_of(cls, obj, msg = nil) click to toggle source

Fails unless obj is a kind of cls.

# File lib/minitest/unit.rb, line 263
def assert_kind_of cls, obj, msg = nil # TODO: merge with instance_of
  msg = message(msg) {
    "Expected #{mu_pp(obj)} to be a kind of #{cls}, not #{obj.class}" }

  assert obj.kind_of?(cls), msg
end
assert_match(exp, act, msg = nil) click to toggle source

Fails unless exp is =~ act.

# File lib/minitest/unit.rb, line 273
def assert_match exp, act, msg = nil
  msg = message(msg) { "Expected #{mu_pp(exp)} to match #{mu_pp(act)}" }
  assert_respond_to act, :"=~"
  exp = Regexp.new Regexp.escape exp if String === exp and String === act
  assert exp =~ act, msg
end
assert_nil(obj, msg = nil) click to toggle source

Fails unless obj is nil

# File lib/minitest/unit.rb, line 283
def assert_nil obj, msg = nil
  msg = message(msg) { "Expected #{mu_pp(obj)} to be nil" }
  assert obj.nil?, msg
end
assert_operator(o1, op, o2 = UNDEFINED, msg = nil) click to toggle source

For testing with binary operators.

assert_operator 5, :<=, 4
# File lib/minitest/unit.rb, line 296
def assert_operator o1, op, o2 = UNDEFINED, msg = nil
  return assert_predicate o1, op, msg if UNDEFINED == o2
  msg = message(msg) { "Expected #{mu_pp(o1)} to be #{op} #{mu_pp(o2)}" }
  assert o1.__send__(op, o2), msg
end
assert_output(stdout = nil, stderr = nil) click to toggle source

Fails if stdout or stderr do not output the expected results. Pass in nil if you don’t care about that streams output. Pass in “” if you require it to be silent.

See also: assert_silent

# File lib/minitest/unit.rb, line 309
def assert_output stdout = nil, stderr = nil
  out, err = capture_io do
    yield
  end

  x = assert_equal stdout, out, "In stdout" if stdout
  y = assert_equal stderr, err, "In stderr" if stderr

  (!stdout || x) && (!stderr || y)
end
assert_predicate(o1, op, msg = nil) click to toggle source

For testing with predicates.

assert_predicate str, :empty?

This is really meant for specs and is front-ended by assert_operator:

str.must_be :empty?
# File lib/minitest/unit.rb, line 329
def assert_predicate o1, op, msg = nil
  msg = message(msg) { "Expected #{mu_pp(o1)} to be #{op}" }
  assert o1.__send__(op), msg
end
assert_raises(*exp) click to toggle source

Fails unless the block raises one of exp

# File lib/minitest/unit.rb, line 337
def assert_raises *exp
  msg = "#{exp.pop}\n" if String === exp.last

  should_raise = false
  begin
    yield
    should_raise = true
  rescue MiniTest::Skip => e
    details = "#{msg}#{mu_pp(exp)} exception expected, not"

    if exp.include? MiniTest::Skip then
      return e
    else
      raise e
    end
  rescue Exception => e
    details = "#{msg}#{mu_pp(exp)} exception expected, not"
    assert(exp.any? { |ex|
             ex.instance_of?(Module) ? e.kind_of?(ex) : ex == e.class
           }, exception_details(e, details))

    return e
  end

  exp = exp.first if exp.size == 1
  flunk "#{msg}#{mu_pp(exp)} expected but nothing was raised." if
    should_raise
end
assert_respond_to(obj, meth, msg = nil) click to toggle source

Fails unless obj responds to meth.

# File lib/minitest/unit.rb, line 369
def assert_respond_to obj, meth, msg = nil
  msg = message(msg) {
    "Expected #{mu_pp(obj)} (#{obj.class}) to respond to ##{meth}"
  }
  assert obj.respond_to?(meth), msg
end
assert_same(exp, act, msg = nil) click to toggle source

Fails unless exp and act are equal?

# File lib/minitest/unit.rb, line 379
def assert_same exp, act, msg = nil
  msg = message(msg) {
    data = [mu_pp(act), act.object_id, mu_pp(exp), exp.object_id]
    "Expected %s (oid=%d) to be the same as %s (oid=%d)" % data
  }
  assert exp.equal?(act), msg
end
assert_send(send_ary, m = nil) click to toggle source

send_ary is a receiver, message and arguments.

Fails unless the call returns a true value TODO: I should prolly remove this from specs

# File lib/minitest/unit.rb, line 393
def assert_send send_ary, m = nil
  recv, msg, *args = send_ary
  m = message(m) {
    "Expected #{mu_pp(recv)}.#{msg}(*#{mu_pp(args)}) to return true" }
  assert recv.__send__(msg, *args), m
end
assert_silent() click to toggle source

Fails if the block outputs anything to stderr or stdout.

See also: assert_output

# File lib/minitest/unit.rb, line 405
def assert_silent
  assert_output "", "" do
    yield
  end
end
assert_throws(sym, msg = nil) click to toggle source

Fails unless the block throws sym

# File lib/minitest/unit.rb, line 414
def assert_throws sym, msg = nil
  default = "Expected #{mu_pp(sym)} to have been thrown"
  caught = true
  catch(sym) do
    begin
      yield
    rescue ArgumentError => e     # 1.9 exception
      default += ", not #{e.message.split(/ /).last}"
    rescue NameError => e         # 1.8 exception
      default += ", not #{e.name.inspect}"
    end
    caught = false
  end

  assert caught, message(msg) { default }
end
capture_io() click to toggle source

Captures $stdout and $stderr into strings:

out, err = capture_io do
  warn "You did a bad thing"
end

assert_match %r%bad%, err
# File lib/minitest/unit.rb, line 440
def capture_io
  require 'stringio'

  orig_stdout, orig_stderr         = $stdout, $stderr
  captured_stdout, captured_stderr = StringIO.new, StringIO.new
  $stdout, $stderr                 = captured_stdout, captured_stderr

  yield

  return captured_stdout.string, captured_stderr.string
ensure
  $stdout = orig_stdout
  $stderr = orig_stderr
end
diff(exp, act) click to toggle source

Returns a diff between exp and act. If there is no known diff command or if it doesn’t make sense to diff the output (single line, short output), then it simply returns a basic comparison between the two.

# File lib/minitest/unit.rb, line 98
def diff exp, act
  require "tempfile"

  expect = mu_pp_for_diff exp
  butwas = mu_pp_for_diff act
  result = nil

  need_to_diff =
    MiniTest::Assertions.diff &&
    (expect.include?("\n")    ||
     butwas.include?("\n")    ||
     expect.size > 30         ||
     butwas.size > 30         ||
     expect == butwas)

  return "Expected: #{mu_pp exp}\n  Actual: #{mu_pp act}" unless
    need_to_diff

  Tempfile.open("expect") do |a|
    a.puts expect
    a.flush

    Tempfile.open("butwas") do |b|
      b.puts butwas
      b.flush

      result = `#{MiniTest::Assertions.diff} #{a.path} #{b.path}`
      result.sub!(/^\-\-\- .+/, "--- expected")
      result.sub!(/^\+\+\+ .+/, "+++ actual")

      if result.empty? then
        klass = exp.class
        result = [
                  "No visible difference.",
                  "You should look at your implementation of #{klass}#==.",
                  expect
                 ].join "\n"
      end
    end
  end

  result
end
exception_details(e, msg) click to toggle source

Returns details for exception e

# File lib/minitest/unit.rb, line 458
def exception_details e, msg
  [
   "#{msg}",
   "Class: <#{e.class}>",
   "Message: <#{e.message.inspect}>",
   "---Backtrace---",
   "#{MiniTest::filter_backtrace(e.backtrace).join("\n")}",
   "---------------",
  ].join "\n"
end
flunk(msg = nil) click to toggle source

Fails with msg

# File lib/minitest/unit.rb, line 472
def flunk msg = nil
  msg ||= "Epic Fail!"
  assert false, msg
end
message(msg = nil, ending = ".", &default) click to toggle source

Returns a proc that will output msg along with the default message.

# File lib/minitest/unit.rb, line 480
def message msg = nil, ending = ".", &default
  proc {
    custom_message = "#{msg}.\n" unless msg.nil? or msg.to_s.empty?
    "#{custom_message}#{default.call}#{ending}"
  }
end
mu_pp(obj) click to toggle source

This returns a human-readable version of obj. By default inspect is called. You can override this to use pretty_print if you want.

# File lib/minitest/unit.rb, line 147
def mu_pp obj
  s = obj.inspect
  s = s.encode Encoding.default_external if defined? Encoding
  s
end
mu_pp_for_diff(obj) click to toggle source

This returns a diff-able human-readable version of obj. This differs from the regular mu_pp because it expands escaped newlines and makes hex-values generic (like object_ids). This uses mu_pp to do the first pass and then cleans it up.

# File lib/minitest/unit.rb, line 159
def mu_pp_for_diff obj # TODO: possibly rename
  mu_pp(obj).gsub(/\\n/, "\n").gsub(/0x[a-f0-9]+/, '0xXXXXXX')
end
pass(msg = nil) click to toggle source

used for counting assertions

# File lib/minitest/unit.rb, line 490
def pass msg = nil
  assert true
end
refute(test, msg = nil) click to toggle source

Fails if test is a true value

# File lib/minitest/unit.rb, line 497
def refute test, msg = nil
  msg ||= "Failed refutation, no message given"
  not assert(! test, msg)
end
refute_empty(obj, msg = nil) click to toggle source

Fails if obj is empty.

# File lib/minitest/unit.rb, line 505
def refute_empty obj, msg = nil
  msg = message(msg) { "Expected #{mu_pp(obj)} to not be empty" }
  assert_respond_to obj, :empty?
  refute obj.empty?, msg
end
refute_equal(exp, act, msg = nil) click to toggle source

Fails if exp == act.

For floats use refute_in_delta.

# File lib/minitest/unit.rb, line 516
def refute_equal exp, act, msg = nil
  msg = message(msg) {
    "Expected #{mu_pp(act)} to not be equal to #{mu_pp(exp)}"
  }
  refute exp == act, msg
end
refute_in_delta(exp, act, delta = 0.001, msg = nil) click to toggle source

For comparing Floats. Fails if exp is within delta of act

refute_in_delta Math::PI, (22.0 / 7.0)
# File lib/minitest/unit.rb, line 528
def refute_in_delta exp, act, delta = 0.001, msg = nil
  n = (exp - act).abs
  msg = message(msg) {
    "Expected #{exp} - #{act} (#{n}) to not be < #{delta}"
  }
  refute delta > n, msg
end
refute_in_epsilon(a, b, epsilon = 0.001, msg = nil) click to toggle source

For comparing Floats. Fails if exp and act have a relative error less than epsilon.

# File lib/minitest/unit.rb, line 540
def refute_in_epsilon a, b, epsilon = 0.001, msg = nil
  refute_in_delta a, b, a * epsilon, msg
end
refute_includes(collection, obj, msg = nil) click to toggle source

Fails if collection includes obj

# File lib/minitest/unit.rb, line 547
def refute_includes collection, obj, msg = nil
  msg = message(msg) {
    "Expected #{mu_pp(collection)} to not include #{mu_pp(obj)}"
  }
  assert_respond_to collection, :include?
  refute collection.include?(obj), msg
end
refute_instance_of(cls, obj, msg = nil) click to toggle source

Fails if obj is an instance of cls

# File lib/minitest/unit.rb, line 558
def refute_instance_of cls, obj, msg = nil
  msg = message(msg) {
    "Expected #{mu_pp(obj)} to not be an instance of #{cls}"
  }
  refute obj.instance_of?(cls), msg
end
refute_kind_of(cls, obj, msg = nil) click to toggle source

Fails if obj is a kind of cls

# File lib/minitest/unit.rb, line 568
def refute_kind_of cls, obj, msg = nil # TODO: merge with instance_of
  msg = message(msg) { "Expected #{mu_pp(obj)} to not be a kind of #{cls}" }
  refute obj.kind_of?(cls), msg
end
refute_match(exp, act, msg = nil) click to toggle source

Fails if exp =~ act

# File lib/minitest/unit.rb, line 576
def refute_match exp, act, msg = nil
  msg = message(msg) { "Expected #{mu_pp(exp)} to not match #{mu_pp(act)}" }
  assert_respond_to act, :"=~"
  exp = (/#{Regexp.escape exp}/) if String === exp and String === act
  refute exp =~ act, msg
end
refute_nil(obj, msg = nil) click to toggle source

Fails if obj is nil.

# File lib/minitest/unit.rb, line 586
def refute_nil obj, msg = nil
  msg = message(msg) { "Expected #{mu_pp(obj)} to not be nil" }
  refute obj.nil?, msg
end
refute_operator(o1, op, o2 = UNDEFINED, msg = nil) click to toggle source

Fails if o1 is not op o2. Eg:

refute_operator 1, :>, 2 #=> pass
refute_operator 1, :<, 2 #=> fail
# File lib/minitest/unit.rb, line 597
def refute_operator o1, op, o2 = UNDEFINED, msg = nil
  return refute_predicate o1, op, msg if UNDEFINED == o2
  msg = message(msg) { "Expected #{mu_pp(o1)} to not be #{op} #{mu_pp(o2)}"}
  refute o1.__send__(op, o2), msg
end
refute_predicate(o1, op, msg = nil) click to toggle source

For testing with predicates.

refute_predicate str, :empty?

This is really meant for specs and is front-ended by refute_operator:

str.wont_be :empty?
# File lib/minitest/unit.rb, line 612
def refute_predicate o1, op, msg = nil
  msg = message(msg) { "Expected #{mu_pp(o1)} to not be #{op}" }
  refute o1.__send__(op), msg
end
refute_respond_to(obj, meth, msg = nil) click to toggle source

Fails if obj responds to the message meth.

# File lib/minitest/unit.rb, line 620
def refute_respond_to obj, meth, msg = nil
  msg = message(msg) { "Expected #{mu_pp(obj)} to not respond to #{meth}" }

  refute obj.respond_to?(meth), msg
end
refute_same(exp, act, msg = nil) click to toggle source

Fails if exp is the same (by object identity) as act.

# File lib/minitest/unit.rb, line 629
def refute_same exp, act, msg = nil
  msg = message(msg) {
    data = [mu_pp(act), act.object_id, mu_pp(exp), exp.object_id]
    "Expected %s (oid=%d) to not be the same as %s (oid=%d)" % data
  }
  refute exp.equal?(act), msg
end
skip(msg = nil, bt = caller) click to toggle source

Skips the current test. Gets listed at the end of the run but doesn’t cause a failure exit code.

# File lib/minitest/unit.rb, line 641
def skip msg = nil, bt = caller
  msg ||= "Skipped, no message given"
  raise MiniTest::Skip, msg, bt
end

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