melatonin-ext - Extensions for the melatonin test framework

These packages extend melatonin to provide additional test contexts for testing various 3rd party services.

• Exec
• AWS Lambda

Exec

The Exec extension provides a context for testing a command line application. It can be used to execute commands and check the exit code, stdout, and stderr.

Installation

go get github.com/jefflinse/melatonin-ext/exec

Usage

package main

import (
    osexec "os/exec"
    "github.com/jefflinse/melatonin/mt"
    "github.com/jefflinse/melatonin-ext/aws/exec"
)

func main() {

    mt.RunTests([]mt.TestCase{

        // Test a commmand
        exec.Run("echo").
            WithArgs("Hello, world!").
            ExpectExitCode(0).
            ExpectStdout("Hello, world!"),

        // Supply some env vars
        exec.Run("echo").
            WithArgs("Hello, world!").
            WithEnv(map[string]string{
                "FOO": "baz",
                "BAR": "buz",
            }).
            ExpectStatus(200).
            ExpectPayload("Hello, world!"),

        // Supply your own exec.Cmd to run
        exec.Cmd(osexec.Command("echo", "Hello, world!")).
            ExpectStatus(200).
            ExpectPayload("Hello, world!"),
    })
}

Custom Context

Define a custom context to customize the execution context, such as the environment:

ctx := exec.NewTestContext().
    WithInheritedEnvironment(true).
    WithEnvVars(map[string]string{
        "FIRST":  "foo",
        "SECOND": "bar",
    })

mt.RunTests([]mt.TestCase{

    ctx.Run("echo").
        ExpectStatus(200).
        ExpectPayload("Hello, world!"),
        WithEnvVars(map[string]string{
            "SECOND": "new bar",
            "THIRD": "baz",
        }),
})

// environment for test case:
//  <all inherited env vars from runtime>
//  FIRST=foo
//  SECOND=new bar
//  THIRD=baz

WithInheritedEnvironment(true) instructs the context to inherit the environment variables from the environment that launched the melatonin process. The default is false, meaning that exec test contexts (including the default context) begin with an empty environment by default.

WithEnvVars(map[string]string{}) will overwrite/append environment variables for a context or test case.

AWS Lambda

The Lambda extension provides a context for testing AWS Lambda functions. It can test Go handler functions directly as unit tests, or it can invoke deployed functions in AWS for performing E2E tests.

Installation

go get github.com/jefflinse/melatonin-ext/aws

Usage

package main

import (
    "github.com/jefflinse/melatonin/mt"
    "github.com/jefflinse/melatonin-ext/aws/lambda"
)

func myHandler(ctx context.Context, event interface{}) (interface{}, error) {
    return "Hello, world!", nil
}

func main() {

    mt.RunTests([]mt.TestCase{

        // Test a Go handler function directly
        lambda.Handle(myHandler).
            ExpectPayload("Hello, world!"),

        // Test a Lambda function by name...
        lambda.Invoke("my-lambda-function").
            ExpectStatus(200).
            ExpectPayload("Hello, world!"),

        // ...or by ARN
        lambda.Invoke("arn:aws:lambda:us-west-2:123456789012:function:my-lambda-function").
            ExpectStatus(200).
            ExpectPayload("Hello, world!"),
    })
}

Custom Context

Define a custom context to customize the AWS Lambda service, including the AWS session:

import (
    "github.com/aws/aws-sdk-go/aws/session"
    lambdasvc "github.com/aws/aws-sdk-go/service/lambda"
)

lambdaService := lambdasvc.New(aws.Must(aws.NewSession(
    aws.WithRegion("us-west-2"),
)))

ctx := lambda.NewTestContext(lambdaService)

mt.RunTests([]mt.TestCase{

    ctx.Invoke("my-lambda-function").
        ExpectStatus(200).
        ExpectPayload("Hello, world!"),
})

Use Mock Lambda APIs

A Lambda test context can be created using any type that satisfies the LambdaAPI interface, making it simple to substitute your own mock Lambda implementation for testing.

import "github.com/aws/aws-sdk-go/service/lambda"

type LambdaAPI interface {
    Invoke(input *lambda.InvokeInput) (*lambda.InvokeOutput, error)
}