Expectations

test.NewResponseExpected defines the contract that must comply with an HTTP response.

It is possible to validate the status code, the headers, cookies and body. The omitted properties do not restrict the corresponding response.

Properties

Property	Description
Status	HTTP status code expected.
Headers	Rules applied to headers.
Cookies	Rules applied to cookies.
Body	Rules applied to the body.

Status

Status requires a specific status code.

gox

expected := test.NewResponseExpected{Status: 200}

The zero value omits this validation. ctx.Response are compared to the indicated value.

Headers

test.ExpectedHeaders provides four types of rule:

Method	Behavior
`Equal(values)`	It demands exactly the indicated headers and values.
`Contains(values)`	It requires the indicated headers and allows additional headers.
`NotContains(values)`	Reject the indicated headers and values.
`Custom(values)`	Apply a different comparator to each header.

gox

expected := test.NewResponseExpected{
	Headers: test.ExpectedHeaders.Contains(test.Map{
		"Content-Type": "application/json; charset=utf-8",
	}),
}

The names of the headers are compared without depending on capital or lower capital.

Cookies

test.ExpectedCookies offers Equal(), Contains(), NotContains() and Custom() for the same purpose as the header rules.

gox

expected := test.NewResponseExpected{
	Cookies: test.ExpectedCookies.Contains(test.Map{
		"language": "es",
	}),
}

The validation compares the name and value of each cookie returned.

Body

test.ExpectedBody includes the following rules:

Method	Behavior
`Equal(content)`	It requires the full text.
`NotEqual(content)`	Reject the full text.
`Contains(patterns...)`	It requires one or more fragments.
`NotContains(patterns...)`	Reject one or more fragments.
`JSONEqual(value)`	It demands the full JSON value.
`JSONNotEqual(value)`	Reject the full JSON value.
`JSONContains(value)`	It demands a JSON subset.
`JSONNotContains(value)`	Reject a JSON subset.
`Snapshot(file)`	Compare the body with a file.
`Custom(rules...)`	It combines several body rules.

gox

expected := test.NewResponseExpected{
	Status: 200,
	Body: test.ExpectedBody.JSONContains(test.Map{
		"name": "George",
	}),
}

JSONContains() allows additional properties in the response. snapshots are useful when a complete document stored in a file must be validated.

Custom Comparators

test.Expect provides reusable comparators for Custom():

Method	Validation
`Equal(value)`	The value exists and is the same.
`NotEqual(value)`	The value is not the same.
`Contains(value)`	The text contains the fragment.
`NotContains(value)`	The text does not contain the fragment.
`Exists()`	The value exists.
`NotExists()`	The value does not exist.

gox

expected := test.NewResponseExpected{
	Headers: test.ExpectedHeaders.Custom(map[string]test.ExpectedStringRule{
		"Content-Type": test.Expect.Contains("application/json"),
		"X-Request-ID": test.Expect.Exists(),
	}),
}

Integration with Go

The expectations implement specific interfaces for headers, cookies and bodies. Each factory returns a value that meets the corresponding interface and can be stored in a variable before building the contract.

JSON matchers decode the response before comparing their values. This prevents the order of properties or the numerical representation of JSON from converting equivalent responses into failures.

Best practices

It only applies to aspects which are part of the public contract.
Use Contains() where the response may include legitimate additional data.
He prefers the JSON matchers for JSON responses.
Use Custom() when each field needs a different rule.
Book snapshots for full and stable content.

Next step

Continue with Actions to prove invocation and results of Actions.

Actions