Rspec::Bash
Run your shell script in a mocked environment to test its behavior using RSpec.
Features
- Test bash functions, entire scripts and inline scripts
- Stub shell commands and their exitstatus and outputs
- Partial mocks of functions
- Control multiple outputs (through STDOUT, STDERR or files)
- Verify STDIN, STDOUT, STDERR
- Verify command was called with specific argument sequence
- Verify command was called correct number of times
- Supports RSpec matchers
Installation
Add this line to your application’s Gemfile:
ruby
gem 'rspec-bash'
And then execute:
$ bundle
Or install it yourself as:
$ gem install rspec-bash
You can setup rspec-bash globally for your spec suite:
in spec_helper.rb
:
```ruby require ‘rspec/bash’
RSpec.configure do |c| c.include Rspec::Bash end ```
Usage
see specs in spec/integration folder:
Running script through stubbed env:
```ruby require ‘rspec/bash’
describe ‘my shell script’ do include Rspec::Bash
let(:stubbed_env) { create_stubbed_env }
it 'runs the script' do
stdout, stderr, status = stubbed_env.execute(
'my-shell-script.sh',
{ 'OPTIONAL_ENV' => 'env vars' }
)
expect(status.exitstatus).to eq 0
end end ```
Choosing a stub type
The stubbed functions/commands for the test runner were traditionally built with ruby. A faster alternative stub, written in bash, has recently been introduced, and is the current default. This can be configured, however, as shown.
For ruby:
ruby
let(:stubbed_env) { create_stubbed_env(StubbedEnv::RUBY_STUB) }
For bash (default, if not provided):
ruby
let(:stubbed_env) { create_stubbed_env(StubbedEnv::BASH_STUB) }
Via environment variable:
bash
export RSPEC_BASH_STUB_TYPE=ruby_stub
# <run your tests here>
...
Stubbing commands:
```ruby let(:stubbed_env) { create_stubbed_env } let!(:bundle) { stubbed_env.stub_command(‘bundle’) } let!(:absolute_command) { stubbed_env.stub_command(‘/path/to/bundle’) } let!(:relative_command) { stubbed_env.stub_command(‘./path/to/bundle’) }
it ‘is stubbed’ do stubbed_env.execute ‘my-script.sh’ expect(bundle).to be_called_with_arguments(‘install’) expect(absolute_command).to be_called_with_arguments(‘hello’) expect(relative_command).to be_called_with_arguments(‘world’) end ```
Changing exitstatus of stubs:
ruby
stubbed_env.stub_command('rake').returns_exitstatus(5)
ruby
stubbed_env.stub_command('rake').with_args('spec').returns_exitstatus(3)
Stubbing output:
```ruby let(:rake_stub) { stubbed_env.stub_command(‘rake’) }
rake_stub.outputs(‘informative message’, to: :stdout) .outputs(‘error message’, to: :stderr) .outputs(‘log contents’, to: ‘logfile.log’) # creates ‘prefix-foo.txt’ when called as ‘rake convert foo’ .outputs(‘converted result’, to: [‘prefix-‘, :arg2, ‘.txt’]) ```
Verifying stdin:
```ruby let(:stubbed_env) { create_stubbed_env }
it ‘verifies stdin with no args’ do cat_stub = stubbed_env.stub_command(‘cat’)
expect(cat_stub.stdin).to eql 'hello' end
it ‘verifies stdin with args’ do mail_stub = stubbed_env.stub_command(‘mail’)
expect(mail_stub.with_args('-s', 'hello').stdin).to eql 'world' end ```
Test entire script, specific function or inline script
ruby
stubbed_env.execute('./path/to/script.sh')
ruby
stubbed_env.execute_function(
'./path/to/script.sh',
'overridden_function'
)
ruby
stubbed_env.execute_inline(<<-multiline_script
stubbed_command first_argument second_argument
multiline_script
)
Check that mock was called with specific arguments
```ruby stubbed_env.execute_inline(«-multiline_script stubbed_command first_argument second_argument multiline_script )
it ‘correctly identifies the called arguments’ do expect(@command).to be_called_with_arguments(‘first_argument’, ‘second_argument’) end ```
Check that mock was not called with any arguments
ruby
expect(@command).to be_called_with_no_arguments
Check that mock was called a certain number of times
```ruby @actual_stdout, @actual_stderr, @actual_status = stubbed_env.execute_inline(«-multiline_script stubbed_command duplicated_argument stubbed_command duplicated_argument stubbed_command once_called_argument multiline_script
expect(@command).to be_called_with_arguments(‘duplicated_argument’).times(2) expect(@command).to be_called_with_arguments(‘once_called_argument’).times(1) end ```
Supports RSpec matchers
```ruby it ‘stub call with a wildcard used for an argument’ do grep_mock = stubbed_env.stub_command(‘grep’) grep_mock.with_args(‘-r’, anything).outputs(‘output from grep’)
expect(command).to be_called_with_arguments(‘output from grep’) end ```
ruby
it 'correctly matches when wildcard is used for arguments' do
expect(@command).to be_called_with_arguments(anything, 'second_argument', anything)
end
ruby
it 'matches any arguments' do
expect(@command).to be_called_with_arguments
end
ruby
it 'matches all arguments' do
expect(@command).to be_called_with_arguments(any_args)
end
ruby
it 'matches any String argument' do
expect(@command).to be_called_with_arguments(instance_of(String))
end
ruby
it 'matches using regexp' do
expect(@command).to be_called_with_arguments(/s..arg/)
end
Pitfalls and known issues
-
Use
$BASH_SOURCE[0]
instead of$0
in your Bash scripts when trying to get the directory that your called script is in. This is a good habit to use when writing scripts as$0
should rarely be used.$0
also has some ramifications when using this gem; it will always bebash
and will not be the name of the script. Please see https://www.gnu.org/software/bash/manual/bashref.html#Positional-Parameters for more information on$0
-
The
execute_function()
method is recommended to be used only when testing Bash libraries. This is because it needs to source the entire file to run the function under test, so any executable code in the script will be run even if it is outside of the function being tested -
The current form of stub injection does not allow for stubs to be picked up by other commands. Ex.
xargs stubbed_command
will result in thestubbed_command
not being found. There is a pending issue for this. ## More examples
see the spec/integration folder
Supported ruby versions
Ruby 2+, no JRuby, due to issues with Open3.capture3
Contributing
- Fork it (https://github.com/mdurban/rspec-bash)
- Create your feature branch (
git checkout -b my-new-feature
) - Commit your changes (
git commit -am 'Add some feature'
) - Push to the branch (
git push origin my-new-feature
) - Create a new Pull Request