Data providers

bashunit offers a way to parameterize your test functions with data providers. Ideal when you want to execute the same test function multiple times, each with a different set of arguments.

Defining a data provider

You can add a special comment @data_provider before a test function to specify an auxiliary function. This function controls how many times the test will run and what arguments it will receive.

A data provider function is specified as follows:

Note: The previous # data_provider syntax is still supported but deprecated. Prefer using the @ prefix going forward.

Example

# @data_provider provider_function
function test_my_test_case() {
  ...
}

Implementing a data provider

A data provider function contains one or more data_set lines. Each data_set results in a separate run of the test function with the individual data_set arguments being passed to it as positional arguments ($1, $2, ...).

Each run is treated as a separate test, so it can pass or fail independently. Plus, set_up and tear_down are called before and after each run. This reduces code repetition and helps create related tests more efficiently.

A data provider function is implemented as follows:

Example

function provider_function() {
  data_set "one"
  data_set "two" "three"
  data_set "value containing spaces"
  data_set "" "first value is empty"
}

Note: The previous variant of using echo to define data within a data provider provider is still supported but deprecated, as it does not support empty values or values containing spaces. Prefer using the data_set function going forward.

Interpolating arguments in test names

You can reference the values provided by a data provider directly in the test function name using placeholders like ::1::, ::2::, ... matching the argument position.

example_test.sh

# @data_provider fizz_numbers
function test_returns_fizz_when_multiple_of_::1::_like_::2::_given() {
  # ...
}

function fizz_numbers() {
  data_set 3 4
  data_set 3 6
}

Output

Running example_test.sh
✓ Passed: Returns fizz when multiple of '3' like '4' given
✓ Passed: Returns fizz when multiple of '3' like '6' given

Multiple args in one call

example_test.sh

# @data_provider provider_directories
function test_directories_exists() {
  local dir1=$1
  local dir2=$2
  local dir3=$3

  assert_directory_exists "$dir1"
  assert_directory_exists "$dir2"
  assert_directory_exists "$dir3"
}

function provider_directories() {
  data_set "/usr" "/etc" "/var"
}

Output

Running example_test.sh
✓ Passed: Directories exists ('/usr', '/etc', '/var')

Single arg in multiple calls

example_test.sh

# @data_provider provider_directories
function test_directory_exists() {
  local directory=$1

  assert_directory_exists "$directory"
}

function provider_directories() {
  data_set "/usr"
  data_set "/etc"
  data_set "/var"
}

Output

Running example_test.sh
✓ Passed: Directory exists ('/usr')
✓ Passed: Directory exists ('/etc')
✓ Passed: Directory exists ('/var')

Multiple args in multiple calls

example_test.sh

# @data_provider provider_directories
function test_directory_exists() {
  local outro=$1
  local directory=$2

  assert_equals "outro" "$outro"
  assert_directory_exists "$directory"
}

function provider_directories() {
  data_set "outro" "/usr"
  data_set "outro" "/etc"
  data_set "outro" "/var"
}

Output

Running example_test.sh
✓ Passed: Directory exists ('outro', '/usr')
✓ Passed: Directory exists ('outro', '/etc')
✓ Passed: Directory exists ('outro', '/var')