Test Script Examples

Copy-paste patterns for the most common API testing scenarios. Each example is self-contained and ready to drop into the Test Script editor of any request.

Checking Status Codes

Expect exactly 200

fc.test("Returns 200 OK", function () {
    fc.response.to.have.status(200);
});

Expect one of several success codes

Useful for POST endpoints that return 200 or 201 depending on whether the resource was created or already existed:

fc.test("Request succeeded", function () {
    fc.expect(fc.response.code).to.be.oneOf([200, 201]);
});

Expect any 2xx status

fc.test("Response is a success", function () {
    fc.response.to.be.ok;
});

Expect a specific error

When deliberately testing that an invalid request is rejected:

fc.test("Missing fields returns 400", function () {
    fc.response.to.have.status(400);
});

Checking the Response Body

Check that a field exists

fc.test("Response has an id", function () {
    var body = fc.response.json();
    fc.expect(body.id).to.exist;
});

Check a field value

fc.test("User is active", function () {
    var body = fc.response.json();
    fc.expect(body.status).to.equal("active");
});

Check a nested field

fc.test("Billing address has a country", function () {
    var body = fc.response.json();
    fc.expect(body.billing.address.country).to.exist;
});

Check a field is a number above zero

fc.test("Price is positive", function () {
    var body = fc.response.json();
    fc.expect(body.price).to.be.a("number");
    fc.expect(body.price).to.be.above(0);
});

Check an array is not empty

fc.test("Results list is not empty", function () {
    var body = fc.response.json();
    fc.expect(body.results).to.be.an("array");
    fc.expect(body.results).to.have.lengthOf.at.least(1);
});

Check that a value is one of a known set

fc.test("Role is valid", function () {
    var body = fc.response.json();
    fc.expect(body.role).to.be.oneOf(["admin", "editor", "viewer"]);
});

Check the body contains a specific string

fc.test("Success message is present", function () {
    fc.expect(fc.response.text()).to.include("successfully created");
});

JSON Schema Validation

Use this to catch structural changes — renamed fields, wrong types, missing required fields — without writing individual assertions for each property.

Validate a user object

fc.test("User object matches expected schema", function () {
    fc.response.to.have.jsonSchema({
        type: "object",
        required: ["id", "name", "email"],
        properties: {
            id:        { type: "integer" },
            name:      { type: "string", minLength: 1 },
            email:     { type: "string", format: "email" },
            createdAt: { type: "string" }
        }
    });
});

Validate a list response

fc.test("Paginated response matches schema", function () {
    fc.response.to.have.jsonSchema({
        type: "object",
        required: ["data", "total", "page"],
        properties: {
            data:  { type: "array" },
            total: { type: "integer", minimum: 0 },
            page:  { type: "integer", minimum: 1 }
        }
    });
});

Checking Headers

Check a header is present

fc.test("Has content type header", function () {
    fc.response.to.have.header("content-type");
});

Check a header value

fc.test("Content type is JSON", function () {
    var contentType = fc.response.headers.get("content-type");
    fc.expect(contentType).to.include("application/json");
});

Check rate limit headers

fc.test("Rate limit headers are present", function () {
    fc.response.to.have.header("x-ratelimit-limit");
    fc.response.to.have.header("x-ratelimit-remaining");
});

fc.test("Rate limit not exceeded", function () {
    var remaining = parseInt(fc.response.headers.get("x-ratelimit-remaining"));
    fc.expect(remaining).to.be.above(0);
});

Response Timing

Ensure a fast response

fc.test("Responds in under 500ms", function () {
    fc.expect(fc.response.responseTime).to.be.below(500);
});

Warn on slow response (soft limit)

fc.test("Response time is acceptable", function () {
    fc.expect(fc.response.responseTime).to.be.below(2000);
});

Authentication Flows — Chaining Requests

The most common use of test scripts: extract a token from a login response and store it so subsequent requests can use it.

Put this on your login or token endpoint:

fc.test("Login succeeded", function () {
    fc.expect(fc.response.code).to.equal(200);
});

fc.test("Access token is present", function () {
    var body = fc.response.json();
    fc.expect(body.access_token).to.exist;
    fc.expect(body.access_token).to.be.a("string");
    fc.expect(body.access_token.length).to.be.above(0);

    // Store it — all subsequent requests in this run can use {{authToken}}
    fc.environment.set("authToken", body.access_token);
});

Then add Authorization: Bearer {{authToken}} to the headers of every subsequent request. The Collection Runner substitutes the value automatically.

fc.test("Tokens are present", function () {
    var body = fc.response.json();
    fc.expect(body.access_token).to.exist;
    fc.expect(body.refresh_token).to.exist;

    fc.environment.set("authToken", body.access_token);
    fc.environment.set("refreshToken", body.refresh_token);
});

Store a created resource's ID for later requests

Put this on a POST /resources endpoint:

fc.test("Resource was created", function () {
    fc.expect(fc.response.code).to.equal(201);
});

fc.test("Store new resource ID", function () {
    var id = fc.response.json().id;
    fc.expect(id).to.exist;
    fc.environment.set("resourceId", id.toString());
});

Use {{resourceId}} in the URL of subsequent GET, PUT, and DELETE requests:

GET https://api.example.com/resources/{{resourceId}}

CRUD Sequence

A full create-read-update-delete sequence. Each script stores the result so the next request can use it.

POST /users — Create:

fc.test("User created", function () {
    fc.expect(fc.response.code).to.equal(201);
    var body = fc.response.json();
    fc.expect(body.id).to.exist;
    fc.environment.set("userId", body.id.toString());
});

GET /users/ — Read:

fc.test("User found", function () {
    fc.response.to.have.status(200);
    var body = fc.response.json();
    fc.expect(body.id.toString()).to.equal(fc.environment.get("userId"));
});

PUT /users/ — Update:

fc.test("User updated", function () {
    fc.response.to.have.status(200);
    var body = fc.response.json();
    fc.expect(body.name).to.equal("Updated Name");
});

DELETE /users/ — Delete:

fc.test("User deleted", function () {
    fc.expect(fc.response.code).to.be.oneOf([200, 204]);
});

Error Handling Scenarios

Validate that a 400 includes an error message

fc.test("Error response has a message", function () {
    fc.expect(fc.response.code).to.equal(400);
    var body = fc.response.json();
    fc.expect(body.message).to.exist;
    fc.expect(body.message).to.be.a("string");
});

Validate specific validation errors

fc.test("Validation errors list specific fields", function () {
    var body = fc.response.json();
    fc.expect(body.errors).to.be.an("array");
    var fields = body.errors.map(function(e) { return e.field; });
    fc.expect(fields).to.include("email");
});

Expect 401 when no token is provided

fc.test("Returns 401 without auth", function () {
    fc.response.to.be.unauthorized;
});

fc.test("Error body has a message", function () {
    var body = fc.response.json();
    fc.expect(body.message).to.include("Unauthorized");
});

Pagination

Check a paginated list response

fc.test("Returns a page of results", function () {
    var body = fc.response.json();

    fc.expect(body.data).to.be.an("array");
    fc.expect(body.data.length).to.be.at.most(20); // max page size

    fc.expect(body.page).to.be.a("number");
    fc.expect(body.total).to.be.a("number");
});

Store the next page cursor

fc.test("Cursor is present for next page", function () {
    var body = fc.response.json();
    if (body.nextCursor) {
        fc.environment.set("nextCursor", body.nextCursor);
    }
});

Conditional Skipping and Flow Control

Stop the run if a critical step fails

If a login request fails, there is no point running the rest of the collection — all subsequent requests will fail with 401 anyway:

fc.test("Login succeeded", function () {
    if (fc.response.code !== 200) {
        fc.execution.abort();
    }
    fc.expect(fc.response.code).to.equal(200);
});

Skip cleanup if setup failed

var created = fc.environment.get("resourceId");
if (!created) {
    fc.execution.setNextRequest("End of Suite"); // jump past cleanup
}

Debugging a Failing Test

When a test is failing and you cannot see why, log the response to the Console:

console.log("Status:", fc.response.code);
console.log("Body:", fc.response.text());

var body = fc.response.json();
console.log("Parsed:", JSON.stringify(body, null, 2));

Open the Console panel (`Cmd/Ctrl + ``) to see the output. In the Collection Runner, these logs appear in the detail panel for each result row.

Test Script Examples

Test Script Examples

Checking Status Codes

Expect exactly 200

Expect one of several success codes

Expect any 2xx status

Expect a specific error

Checking the Response Body

Check that a field exists

Check a field value

Check a nested field

Check a field is a number above zero

Check an array is not empty

Check that a value is one of a known set

Check the body contains a specific string

JSON Schema Validation

Validate a user object

Validate a list response

Checking Headers

Check a header is present

Check a header value

Check rate limit headers

Response Timing

Ensure a fast response

Warn on slow response (soft limit)

Authentication Flows — Chaining Requests

Login and store access token

Login and store both access and refresh token

Store a created resource's ID for later requests

CRUD Sequence

Error Handling Scenarios

Validate that a 400 includes an error message

Validate specific validation errors

Expect 401 when no token is provided

Pagination

Check a paginated list response

Store the next page cursor

Conditional Skipping and Flow Control

Stop the run if a critical step fails

Skip cleanup if setup failed

Debugging a Failing Test