karatelabs/karate · warning

skipping scenario outline in mock

Error message

skipping scenario outline in mock - {}:{}

What it means

MockHandler iterates the feature's sections to find a scenario matching the incoming mock HTTP request. Scenario Outlines cannot be executed by the mock server (mocking resolves a single concrete scenario per request), so any outline section is skipped with this warning and matching continues with the plain scenarios.

Solutions

1. Split the mock feature so each concrete case is a plain Scenario (no Examples) with the request matchers the mock should respond to.
2. Generate/unroll the outline rows into separate scenarios in the mock feature.
3. Keep a dedicated mock-only feature file separate from the test features.
4. If the outline behavior is needed, handle it in a custom mock implementation or request handler rather than a Scenario Outline.

Example fix

// before
Scenario Outline: mock user
  * def name = '<name>'
  Examples: | name |
           | bob |
// after
Scenario: mock user bob
  * def name = 'bob'

// Before starting the mock, assert the feature has no outlines
for (FeatureSection s : feature.getSections()) {
    if (s.isOutline()) {
        throw new IllegalStateException("mock feature must not contain Scenario Outline at line " + s.getScenarioOutline().getLine());
    }
}

When it happens

Trigger: Starting a Karate mock server (Karate.mockServer / MockHandler) against a feature whose Scenario Outline blocks would be candidates for an incoming request; handleRequest then logs this per outline section and never uses the outline's Examples rows.

Common situations: Pointing a mock at a reused test feature file that contains outlines instead of authoring a dedicated mock feature; a refactor converts a scenario into an outline and mock coverage silently disappears; developers expecting Examples-based responses from the mock.

Understand the failure class

Background: UnsupportedOperationException and "is not supported" errors: when a library deliberately refuses a call — this error's family across 30 libraries.

Related errors

• at least one feature file is required
• def requires '=' assignment
• hook failed
• mock background failed at line
• proceed() can only be called within a mock scenario

AI-assisted analysis of karatelabs/karate@a22eb90246 (2026-09-12). Data as JSON: /api/errors/1b4e1302d46bf38b. Report an issue: GitHub.

Appendix: source

Thrown at karate-core/src/main/java/io/karatelabs/core/MockHandler.java:402

        // Process body for form-urlencoded and multipart
        request.processBody();

        // Find matching scenario and execute
        for (Feature feature : features) {
            ScenarioRuntime runtime = runtimes.get(feature);
            Engine engine = runtime.getEngine();

            // Drop any values marked request-derived by a previous request before this one's
            // bindings are read again, so the identity set never accumulates stale entries.
            runtime.clearRequestDerived();

            // Set up request variables (includes storing HttpRequest for matcher functions)
            setupRequestVariables(engine, request);

            for (FeatureSection section : feature.getSections()) {
                if (section.isOutline()) {
                    logger.warn("skipping scenario outline in mock - {}:{}", feature, section.getScenarioOutline().getLine());
                    continue;
                }

                Scenario scenario = section.getScenario();
                if (isMatchingScenario(scenario, engine)) {
                    return executeScenario(runtime, scenario, request);
                }
            }
        }

        // No match found - return 404
        logger.warn("no scenarios matched, returning 404: {} {}", request.getMethod(), request.getPath());
        return createNotFoundResponse();
    }

    private HttpResponse handleCorsPreFlight(HttpRequest request) {
        HttpResponse response = new HttpResponse();
        response.setStatus(200);

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