# assert_value

Checks that two values are same and "magically" replaces expected value
with the actual in case the new behavior (and new actual value) is correct.
Support two kind of arguments: string and code block.

This check works with both Test/Unit and RSpec. See documentation and examples below:

## Testing String Values

It is better to start with no expected value

    assert_value "foo"

Then run tests as usual with "rake test". As a result you will see
diff between expected and actual values:

    Failure:
    @@ -1,0, +1,1 @@
    +foo
    Accept the new value: yes to all, no to all, yes, no? [Y/N/y/n] (y):

If you accept the new value your test will be automatically modified to

    assert_value "foo", <<-END
        foo
    END

## Testing Block Values

assert_value can take code block as an argument. If executed block raises exception then
exception message is returned as actual value:

    assert_value do
        nil+1
    end

Run tests

    Failure:
    @@ -1,0, +1,1 @@
    +Exception NoMethodError: undefined method `+' for nil:NilClass
    Accept the new value: yes to all, no to all, yes, no? [Y/N/y/n] (y): 

After the new value is accepted you get

    assert_value(<<-END) do
        Exception NoMethodError: undefined method `+' for nil:NilClass
    END
        nil + 1
    end

## Testing Values Stored in Files

Sometimes test string is too large to be inlined into the test source. Put it into the file instead:

    assert_value "foo", log: 'test/log/reference.txt'

## Additional Test/Unit Options:

    --no-interactive skips all questions and just reports failures
    --autoaccept prints diffs and automatically accepts all new actual values
    --no-canonicalize turns off expected and actual value canonicalization (see below for details)

Additional options can be passed during both single test file run and rake test run:

In Ruby 1.8:

    ruby test/unit/foo_test.rb -- --autoaccept
    rake test TESTOPTS="-- --autoaccept"

In Ruby 1.9:

    ruby test/unit/foo_test.rb --autoaccept
    rake test TESTOPTS="--autoaccept"

## RSpec

In specs you can either call assert_value directly or use "be_same_value_as" matcher:

    describe "spec with be_same_value_as matcher" do
        it "compares with inline value" do
            expect("foo").to be_same_value_as <<-END
                foo
            END
        end

        it "compares with inline block" do
            expect { "foo" }.to be_same_value_as <<-END
                foo
            END
        end

        it "compares with value in file" do
            expect("foo").to be_same_value_as(:log => 'test/logs/assert_value_with_files.log.ref')
        end
    end


## Canonicalization:

Before comparing expected and actual strings, assert_value canonicalizes both using these rules:

- indentation is ignored (except for indentation  relative to the first line of the expected/actual string)
- ruby-style comments after "#" are ignored
- empty lines are ignored
- trailing whitespaces are ignored

You can turn canonicalization off with --no-canonicalize option. This is useful
when you need to regenerate expected test strings.
To regenerate the whole test suite, run:

In Ruby 1.8:

    rake test TESTOPTS="-- --no-canonicalize --autoaccept"

In Ruby 1.9:

    rake test TESTOPTS="--no-canonicalize --autoaccept"


## Changelog

- 1.2: Rails 4.1 and minitest gem support
- 1.1: RSpec support
- 1.0: Rename to assert_value
- 0.7: Support Ruby 1.9's MiniTest
- 0.6: Support test execution on Mac
- 0.5: Support code blocks to assert_same
- 0.4: Added support for code blocks as argument
- 0.3: Ruby 1.9 is supported
- 0.2: Make assert_same useful as a standalone gem. Bugfixes
- 0.1: Initial release