Placebo for Bash

This repository is a fork of alexharv074's bash_placebo.

Major difference between the two projects is this project is built to generate mock commands for unit testing with any bash command while the original is built specifically to mock aws cli commands.

Installation

The tool can be installed just by copying the script from the master branch into your path somewhere. E.g.

curl -o /usr/local/bin/placebo \
    https://raw.githubusercontent.com/JasonTheDeveloper/bash_placebo/master/placebo

Quick Start

Using record mode to save response in a file test/fixtures/:

. placebo
pill_attach data_path=test/fixtures/
pill_record

Now that you're in record mode, you can go ahead and enter your commands. Make sure you put mock in front of your command.

For example:

mock your_command foo

Reading those responses back in the context of your unit tests:

. placebo
pill_attach data_path=test/fixtures/
pill_playback

In playback mode, you can enter the commands you mocked earlier while in record mode like normal and Placebo will return the original response.

for example:

your_command foo

Once you're done, you must clean up your shell environment. Not doing so will mean Placebo will still be active and will continue to override your commands mocked earlier.

To clean up:

pill_detach

Testing Placebo

You'll find under test/ a placebo.sh script used to test Placebo.

Dependency

shUnit2
For code coverage:
- Ruby
- bashcov
- simplecov-cobertura

Running Unit Test

With shUnit2 installed, from the root of this project in a new terminal window, run the following command:

bash test/placebo.sh

Collecting Code Coverage

Instead of running the command above to run unit test, we can use bashcov to run our unit test and collect code coverage at the same time!

Before we run bashcov you might want to be able to visually see your coverage results. Inside .simplecov, remove the following lines:

require 'simplecov-cobertura'

SimpleCov.formatter = SimpleCov::Formatter::CoberturaFormatter

Removing the above lines from .simplecov, bashcov will now output the code coverage results as .HTML. Put the lines back will change the output format.

Now run the following command:

 bashcov test/placebo.sh --skip-uncovered

Note: --skip-uncovered will ignore files with 0% coverage.

Once finished, you'll fine a new folder named coverage and inside that folder you'll find a index.html. Open that file in a browser to view your results.

Manual Mocking

If you want to create fake responses manually that can be read in later by Placebo, it is quite simple. They are formatted as case statements. For example:

case "dummy $*" in
'dummy command subcommand some args')
  echo some_response
  ;;
'dummy command subcommand some other args')
  echo some_other_response
  ;;
esac

Spies

A log of all commands can be obtained using the pill_log function, allowing the mocks to be "spies" on commands called.

Using shUnit2, for example:

testCommandsLogged() {
  . $script_under_test
  assertEquals "$(<expected_log)" "$(pill_log)"
}

Contributing

PRs are welcome. To run the tests:

Ensure you have dependencies installed:

ShellCheck
shUnit2

Then run make:

make

Support is available so feel free to raise issues.