Before statements are should statements that run before the current context’s setup. These are especially useful when setting expectations.
class UserControllerTest < Test::Unit::TestCase
context "the index action" do
setup do
@users = [Factory(:user)]
User.stubs(:find).returns(@users)
end
context "on GET" do
setup { get :index }
should_respond_with :success
# runs before "get :index"
before_should "find all users" do
User.expects(:find).with(:all).returns(@users)
end
end
end
end
# File lib/shoulda/context.rb, line 128 def before_should(name, &blk) should(name, :before => blk) { assert true } end
A context block groups should statements under a common set of setup/teardown methods. Context blocks can be arbitrarily nested, and can do wonders for improving the maintainability and readability of your test code.
A context block can contain setup, should, should_eventually, and teardown blocks.
class UserTest < Test::Unit::TestCase
context "A User instance" do
setup do
@user = User.find(:first)
end
should "return its full name"
assert_equal 'John Doe', @user.full_name
end
end
end
This code will produce the method "test: A User instance should return its full name. ".
Contexts may be nested. Nested contexts run their setup blocks from out to in before each should statement. They then run their teardown blocks from in to out after each should statement.
class UserTest < Test::Unit::TestCase
context "A User instance" do
setup do
@user = User.find(:first)
end
should "return its full name"
assert_equal 'John Doe', @user.full_name
end
context "with a profile" do
setup do
@user.profile = Profile.find(:first)
end
should "return true when sent :has_profile?"
assert @user.has_profile?
end
end
end
end
This code will produce the following methods
"test: A User instance should return its full name. "
"test: A User instance with a profile should return true when sent :has_profile?. "
Just like should statements, a context block can exist next to normal def test_the_old_way; end tests. This means you do not have to fully commit to the context/should syntax in a test file.
# File lib/shoulda/context.rb, line 195 def context(name, &blk) if Shoulda.current_context Shoulda.current_context.context(name, &blk) else context = Shoulda::Context.new(name, self, &blk) context.build end end
Returns the class being tested, as determined by the test class name.
class UserTest; described_type; end # => User
# File lib/shoulda/context.rb, line 208 def described_type self.name.gsub(/Test$/, '').constantize end
Should statements are just syntactic sugar over normal Test::Unit test methods. A should block contains all the normal code and assertions you’re used to seeing, with the added benefit that they can be wrapped inside context blocks (see below).
class UserTest < Test::Unit::TestCase
def setup
@user = User.new("John", "Doe")
end
should "return its full name"
assert_equal 'John Doe', @user.full_name
end
end
…will produce the following test:
"test: User should return its full name. "
Note: The part before should in the test name is gleamed from the name of the Test::Unit class.
Should statements can also take a Proc as a :before option. This proc runs after any parent context’s setups but before the current context’s setup.
context "Some context" do
setup { puts("I run after the :before proc") }
should "run a :before proc", :before => lambda { puts("I run before the setup") } do
assert true
end
end
Should statements can also wrap matchers, making virtually any matcher usable in a macro style. The matcher’s description is used to generate a test name and failure message, and the test will pass if the matcher matches the subject.
should validate_presence_of(:first_name).with_message(/gotta be there/)
# File lib/shoulda/context.rb, line 71 def should(name_or_matcher, options = {}, &blk) if Shoulda.current_context Shoulda.current_context.should(name_or_matcher, options, &blk) else context_name = self.name.gsub(/Test/, "") context = Shoulda::Context.new(context_name, self) do should(name_or_matcher, options, &blk) end context.build end end
Just like should, but never runs, and instead prints an ‘X’ in the Test::Unit output.
# File lib/shoulda/context.rb, line 133 def should_eventually(name, options = {}, &blk) context_name = self.name.gsub(/Test/, "") context = Shoulda::Context.new(context_name, self) do should_eventually(name, &blk) end context.build end
Allows negative tests using matchers. The matcher’s description is used to generate a test name and negative failure message, and the test will pass unless the matcher matches the subject.
should_not set_the_flash
# File lib/shoulda/context.rb, line 90 def should_not(matcher) if Shoulda.current_context Shoulda.current_context.should_not(matcher) else context_name = self.name.gsub(/Test/, "") context = Shoulda::Context.new(context_name, self) do should_not(matcher) end context.build end end
Sets the return value of the subject instance method:
class UserTest < Test::Unit::TestCase
subject { User.first }
# uses the existing user
should_validate_uniqueness_of :email
end
# File lib/shoulda/context.rb, line 220 def subject(&block) @subject_block = block end
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