hurl/docs/tutorial/chaining-requests.md

# Chaining Requests

## Adding Another Request

Our basic Hurl file is for the moment:

```hurl
# Checking our home page:
GET http://localhost:8080

HTTP 200
[Asserts]
xpath "string(//head/title)" == "Welcome to Quiz!"
xpath "//button" count == 2
xpath "string((//button)[1])" contains "Play"
xpath "string((//button)[2])" contains "Create"
# Testing content type:
header "Content-Type" == "text/html;charset=UTF-8"
# Testing session cookie:
cookie "JSESSIONID" exists
cookie "JSESSIONID[HttpOnly]" exists
```

We're only running one HTTP request and have already added lots of tests on the response. Don't hesitate to add
many tests, the more asserts you write, the less fragile your tests suite will become.

Now, we want to perform other HTTP requests and keep adding tests. In the same file, we can simply write another
request following our first request. Let's say we want to test that we have a [404 page] on a broken link:

1. Modify `basic.hurl` to add a second request on a broken URL:

```hurl
# Checking our home page:
GET http://localhost:8080

HTTP 200
[Asserts]
xpath "string(//head/title)" == "Welcome to Quiz!"
xpath "//button" count == 2
xpath "string((//button)[1])" contains "Play"
xpath "string((//button)[2])" contains "Create"
# Testing content type:
header "Content-Type" == "text/html;charset=UTF-8"
# Testing session cookie:
cookie "JSESSIONID" exists
cookie "JSESSIONID[HttpOnly]" exists

# Check that we have a 404 response for broken links:
GET http://localhost:8080/not-found

HTTP 404
[Asserts]
header "Content-Type" == "text/html;charset=UTF-8"
xpath "string(//h1)" == "Error 404, Page not Found!"
```

Now, we have two entries in our Hurl file: each entry is composed of one request and one expected response
description.

> In a Hurl file, response descriptions are optional. We could also have written
> our file with only requests:
>
> ```hurl
> GET http://localhost:8080
> GET http://localhost:8080/not-found
> ```
> But it would have performed nearly zero test. This type of Hurl file can be useful
> if you use Hurl to get data for instance.

2. Run `basic.hurl`:

```shell
$ hurl --test basic.hurl
basic.hurl: Running [1/1]
basic.hurl: Success (2 request(s) in 12 ms)
--------------------------------------------------------------------------------
Executed files:  1
Succeeded files: 1 (100.0%)
Failed files:    0 (0.0%)
Duration:        12 ms
```

We can see that the test is still ok, now two requests are being run in sequence, and each response can be
tested independently.

## Test REST API

So far, we have tested two HTML endpoints. We're going to see now how to test a REST API.

Our quiz application exposes a health REST resource, available at <http://localhost:8080/api/health>.
Let's use Hurl to check it.

1. In a shell, use Hurl to test the </api/health> endpoint:

```shell
$ echo 'GET http://localhost:8080/api/health' | hurl
{"status":"RUNNING","reportedDate":"2021-06-06T14:08:27Z","healthy":true,"operationId":425276758}
```

> Being a classic CLI application, we can use the standard input with Hurl to provide requests
> to be executed, instead of a file.

So, our health API returns this JSON resource:

```
{
  "status": "RUNNING",
  "reportedDate": "2021-06-06T14:08:27Z",
  "healthy": true,
  "operationId": 425276758
}
```

We can test it with a [JsonPath assert]. JsonPath asserts have the same structure as XPath asserts: a query
followed by a predicate. A [JsonPath query] is a simple expression to inspect a JSON object.

2. Modify `basic.hurl` to add a third request that asserts our </api/health> REST API:

```hurl
# Checking our home page:
# ...

# Check that we have a 404 response for broken links:
# ...

# Check our health API:
GET http://localhost:8080/api/health

HTTP 200
[Asserts]
header "Content-Type" == "application/json"
jsonpath "$.status" == "RUNNING"
jsonpath "$.healthy" == true
jsonpath "$.operationId" exists
```

Like XPath assert, JsonPath predicate values are typed. String, boolean, number and
collections are supported. Let's practice writing JsonPath asserts by using another API. In our Quiz model, a
quiz is a set of questions, and a question resource is exposed through a
REST API exposed at <http://localhost:8080/api/questions>. We can use it to add checks on getting questions
through the API endpoint.

3. Add JSONPath asserts on the </api/questions> REST APIs:

```hurl
# Checking our home page:
# ...

# Check that we have a 404 response for broken links:
# ...

# Check our health API:
# ...

# Check question API:
GET http://localhost:8080/api/questions?offset=0&size=20&sort=oldest

HTTP 200
[Asserts]
header "Content-Type" == "application/json"
jsonpath "$" count == 20
jsonpath "$[0].id" == "c0d80047"
jsonpath "$[0].title" == "What is a pennyroyal?"
```

> To keep things simple in this tutorial, we have hardcoded mocked data
> in our Quiz application. That's something you don't want to do when building
> your application, you want to build an app production ready. A better way to
> do this should have been to expose a "debug" or "integration" mode on our app
> defined by environment variables. If our app is launched in "integration" mode,
> mocked data is used and asserts can be tested on known values. Our app could also use
> a mocked database, configured in our tests suits.

Note that the question API use query parameters `offset`, `size` and `sort`, that's why we have written the URL with
query parameters <http://localhost:8080/api/questions?offset=0&size=20&sort=oldest>. We can set the query parameters
in the URL, or use a [query parameter section].

4. Use a query parameter section in `basic.hurl`:

```hurl
# Checking our home page:
# ...

# Check that we have a 404 response for broken links:
# ...

# Check our health API:
# ...

# Check question API:
GET http://localhost:8080/api/questions
[QueryStringParams]
offset: 0
size: 20
sort: oldest

HTTP 200
[Asserts]
header "Content-Type" == "application/json"
jsonpath "$" count == 20
jsonpath "$[0].id" == "c0d80047"
jsonpath "$[0].title" == "What is a pennyroyal?"
```

Finally, our basic Hurl file, with four requests, looks like:

```hurl
# Checking our home page:
GET http://localhost:8080

HTTP 200
[Asserts]
xpath "string(//head/title)" == "Welcome to Quiz!"
xpath "//button" count == 2
xpath "string((//button)[1])" contains "Play"
xpath "string((//button)[2])" contains "Create"
# Testing content type:
header "Content-Type" == "text/html;charset=UTF-8"
# Testing session cookie:
cookie "JSESSIONID" exists
cookie "JSESSIONID[HttpOnly]" exists


# Check that we have a 404 response for broken links:
GET http://localhost:8080/not-found

HTTP 404
[Asserts]
header "Content-Type" == "text/html;charset=UTF-8"
xpath "string(//h1)" == "Error 404, Page not Found!"


# Check our health API:
GET http://localhost:8080/api/health

HTTP 200
[Asserts]
header "Content-Type" == "application/json"
jsonpath "$.status" == "RUNNING"
jsonpath "$.healthy" == true
jsonpath "$.operationId" exists


# Check question API:
GET http://localhost:8080/api/questions
[QueryStringParams]
offset: 0
size: 20
sort: oldest

HTTP 200
[Asserts]
header "Content-Type" == "application/json"
jsonpath "$" count == 20
jsonpath "$[0].id" == "c0d80047"
jsonpath "$[0].title" == "What is a pennyroyal?"
```

5. Run `basic.hurl` and check that every assert of every request has been successful:

```shell
$ hurl --test basic.hurl
basic.hurl: Running [1/1]
basic.hurl: Success (4 request(s) in 24 ms)
--------------------------------------------------------------------------------
Executed files:  1
Succeeded files: 1 (100.0%)
Failed files:    0 (0.0%)
Duration:        31 ms
```

## Recap

We can simply chain requests with Hurl, adding asserts on every response. As your Hurl file will grow,
don't hesitate to add many comments: your Hurl file will be a valuable and testable documentation
for your applications.

[404 page]: https://developer.mozilla.org/en-US/docs/Web/HTTP/Status/404
[JsonPath assert]: /docs/asserting-response.md#jsonpath-assert
[JsonPath query]: https://goessner.net/articles/JsonPath/
[query parameter section]: /docs/request.md#query-parameters
[`--test`]: /docs/manual.md#test