# cucumberl
A pure-erlang, open-source, implementation of Cucumber
(http://cukes.info). This provides a subset of the Cucumber feature
definition language.
## Quick Start
You'll need erlang, of course.
To do a build, do...
./rebar3 compile
To run unit tests, do...
./rebar3 eunit
There's are sample feature files (examples/complex_sample/features and
examples/complex_sample/features) and step definitions (in
examples/src). Running `make test` will execute these too.
You can also run them by hand, for example...
examples $ ../cucumberl
Feature: Addition :1
In order to avoid silly mistakes :2
As a math idiot :3
I want to be told the sum of two numbers :4
:5
Scenario: Add two numbers :6
Given I have entered 50 into the calculator :7
And I have entered 70 into the calculator :8
When I press add :9
Then the result should be 120 on the screen :10 ok
:11
etc.....
## Slow Start
So you want to write your own step definitions? No problem. Any
erlang module that implements step definitions should export a step/2
function, with this kind of call signature...
Action(TokenList, State, Info)
Where Action is:
- given
- 'when' or when_
- then
The TokenList parameter is a list of either atoms or strings, such as...
[i, have, entered, "Joe Armstrong", into, the, authors, field]
So for example, the previous TokenList would also be accepted in
a function definition like this:
given([i, have, entered, Name, into, the, authors, field], State, _) ->
{ok, NewState}.
The State parameter is the state the last step function returned in the state field of the tuple. In the above example, this is NewState.
The Info parameter is a tuple of helpful debug information, such as
the {LineText, LineNum}, of what cucumberl is currently processing.
The Info parameter is usually ignored unless you're deep into
debugging your scenario/steps.
Here's how you'd write a few step definition functions, using erlang's
pattern matching.
given([i, have, entered, N, into, the, calculator], _State, _Info) ->
% Your step implementation here.
todo.
'when'([, i, press, add], _, _) ->
% Your step implementation here.
todo.
then([the, result, should, be, Result, on, the, screen], _, _) ->
% Your step implementation here.
todo.
Optionally, you could write your `'when`' as:
when_([, i, press, add], _, _) ->
% Your step implementation here.
todo.
Notice that all the tokens have been atomized (and turned lowercase).
- The atoms `true` and `ok` in the state tuple represent *success* and
print *ok* on the console
- A two-tuple of the form `{failed, Reason}` indicates failure
The above step definitions will match a scenario like the following...
Scenario: Add two numbers
Given I have entered 50 into the calculator
And I have entered 70 into the calculator
When I press add
Then the result should be 120 on the screen
## Running cucumberl
Running cucumberl on the command line is very simple. Just execute the
cucumberl self-contained escript.
To run a feature file through cucumberl using the erlang API...
cucumberl:run(PathToFeatureFile).
For example...
cucumberl:run("./features/sample.feature").
or
cucumberl:run("./features/sample.feature", FeatureDefinitionModule).
The FeatureDefinitionModule parameter is an optional module that
implements the feature and contains the step callbacks. However, it is
only needed when the name of the step implementation is different then
the name of the feature. For example...
cucumberl:run("./features/auction.feature",
auction).
is exactly equivalent to
cucumberl:run("./features/auction.feature").
However, you may want to implement the feature in a different module,
such as ...
cucumberl:run("./features/auction.feature", some_other_module).
perfectly acceptable but not recommended.
## Scenario Outlines
There's basic support for Scenario Outlines, aka Example Tables, in
cucumberl. However, placeholders names should be all lowercase, and
there shouldn't be any blank lines before the "Examples:" label. For
example...
Scenario Outline:
Given I have cleared the calculator
And I have entered <a> into the calculator
And I have entered <b> into the calculator
When I press <op>
Then the result should be <ab> on the screen
Examples:
| a | b | ab | op |
| 1 | 1 | 2 | add |
| 1 | 3 | 3 | multiply |
| 2 | 3 | 6 | multiply |
| 10 | 1 | 11 | add |
See the files examples/simple_sample/src/simple_sample_table.erl and
examples/simple_sample/features/simple_sample_table.feature for more details.
## License
MIT - We made this for you!
## Feedback, or getting in touch
Improvements and patches welcomed -- info@northscale.com
Cheers,
Steve Yen
