bash

Bash

Bash testing with BATS

• Show me the code
  • Implementation
  • Test
• Run this project using 🐳 docker
• Run this project locally

BATS git submodules

⚠️ This project includes BATS git submodules so once you clone the repo you will need to init and update them:

git submodule init
git submodule update

Show me the code

Implementation

1. Create helloMessage function in hello-message.bash:

function helloMessage() {
    echo "Hello World!"
}

2. Create helloConsole function in hello-console.bash:

function helloConsole() {
    local text=$1
    echo "$text"
}

3. Create helloApp function in hello-app.bash:

function helloApp() {
    local messageFn=$1
    local consoleFn=$2
    $consoleFn "$($messageFn)"
}

Note that helloApp function receives the two other functions as parameters and just executes them.

4. Create a main script hello.bash that just loads the 3 required scripts and executes helloApp passing helloMessage and helloConsole functions as parameters:

source "$(dirname "${BASH_SOURCE[0]}")/hello-message.bash"
source "$(dirname "${BASH_SOURCE[0]}")/hello-console.bash"
source "$(dirname "${BASH_SOURCE[0]}")/hello-app.bash"

helloApp helloMessage helloConsole

Test

Following BATS Tutorial > Your first test ...

1. For simplicity create all tests in hello.bats file

2. Configure current directory and load some helper modules in setup function:

setup() {
    load 'test_helper/bats-support/load'
    load 'test_helper/bats-assert/load'

    DIR="$( cd "$( dirname "$BATS_TEST_FILENAME" )" >/dev/null 2>&1 && pwd )"
    PATH="$DIR/../src:$PATH"
}

3. Test helloMessage function using assert_output helper:

@test "helloMessage should return hello world" {
    source hello-message.bash
    run helloMessage

    assert_output "Hello World!"
}

4. Test helloApp function:

@test "helloApp should print hello message" {
    # 4.1 Create a helloMessage function mock
    # that will return "Hello Test!"
    function helloMessageMock() {
        echo "Hello Test!"
    }

    # 4.2 Create a helloConsole function mock
    # that will print parameter passed within "helloConsoleMock[...]"
    function helloConsoleMock() {
        local text=$1
        echo "helloConsoleMock[$text]"
    }

    # 4.3 Load helloApp function, the one we want to test
    source hello-app.bash
    # 4.4 Execute helloApp passing mock functions
    run helloApp helloMessageMock helloConsoleMock

    # 4.5 Assert helloConsoleMock has been called once
    # with the returned message by helloMessageMock
    assert_output "helloConsoleMock[Hello Test!]"
}

5. Test the whole hello.bash script too:

@test "hello.bash should print hello world" {
    run hello.bash

    assert_output "Hello World!"
}

6. Test output should look like:

hello.bats
 ✓ helloMessage should return hello world
 ✓ helloApp should print hello message
 ✓ hello.bash should print hello world

3 tests, 0 failures

Take a look at the other Libraries and Add-ons that may be useful in the future. For example, there is a couple of bats-mock libraries that can be used to mock programs (but unfortunately not able to mock functions).

Run this project using 🐳 docker

• Ensure you have updated BATS git submodules
• Execute ./docker-run.sh
• Once inside the container:
  • Test with ./test/bats/bin/bats test/hello.bats
  • Run with ./src/hello.bash

Run this project locally

Pre-requisites

• Ensure you have bash installed bash --version (this project uses version 5.2)

Run locally

• Ensure you have updated BATS git submodules
• Test with ./test/bats/bin/bats test/hello.bats
• Run with ./src/hello.bash

Create project from scratch

• Create an empty project with src and test folders
• Follow Quick installation guide to install BATS submodules:

git submodule add https://github.com/bats-core/bats-core.git test/bats
git submodule add https://github.com/bats-core/bats-support.git test/test_helper/bats-support
git submodule add https://github.com/bats-core/bats-assert.git test/test_helper/bats-assert