@probitas/core

Core scenario definition types and utilities.

This package provides the fundamental type definitions that represent scenario structures, along with utilities for loading scenario files and filtering scenarios using selectors. It serves as the foundation layer that other Probitas packages build upon.

Links

GitHub Repository
@probitas/probitas - Main package (recommended for most users)

Package	Description
@probitas/builder	Uses these types to build scenarios
@probitas/runner	Executes scenario definitions
@probitas/discover	Discovers scenario files to load

Type Definitions

The type system is designed around immutable data structures:

ScenarioDefinition - Complete scenario with name, options, and entries
StepDefinition - Individual step with function, options, and source
SetupDefinition - Setup hook with cleanup function support
ResourceDefinition - Named resource with fn function
StepContext - Context object passed to all functions
Entry - Discriminated union of step, setup, or resource

Options Types

ScenarioOptions - Scenario-level configuration (tags, default step options)
StepOptions - Step execution settings (timeout, retry strategy)
Import Origin from @probitas/core/origin for file and line information

Function Types

StepFunction - Signature for step execution functions
SetupFunction - Signature for setup hooks (returns cleanup)
ResourceFunction - Signature for resource creation functions
SetupCleanup - Return type of setup functions

Loader Utilities

loadScenarios - Load scenario definitions from file paths
LoadScenariosOptions - Options for the loader

Selector Utilities

Selectors provide powerful filtering capabilities:

applySelectors - Filter scenarios using selector strings
parseSelector - Parse selector string into Selector objects
matchesSelector - Check if a scenario matches a single selector
Selector - Parsed selector object
SelectorType - Type of selector ("tag" or "name")

Installation

deno add jsr:@probitas/core

Interfaces

interface

#ScenarioDefinition

interface ScenarioDefinition

Complete, immutable definition of a scenario.

This is the core type produced by the builder and consumed by the runner. It contains everything needed to execute a scenario: its name, options, and ordered sequence of entries (steps, resources, setups).

Examples

Typical scenario structure

import type { ScenarioDefinition } from "@probitas/core";

// Created by: scenario("Login Flow").step(...).build()
const definition: ScenarioDefinition = {
  name: "Login Flow",
  tags: ["auth", "smoke"],
  steps: [
    {
      kind: "resource",
      name: "api",
      fn: () => fetch,
      timeout: 30000,
      retry: { maxAttempts: 1, backoff: "linear" },
    },
    {
      kind: "step",
      name: "Login",
      fn: () => {},
      timeout: 30000,
      retry: { maxAttempts: 1, backoff: "linear" },
    },
    {
      kind: "step",
      name: "Verify",
      fn: () => {},
      timeout: 30000,
      retry: { maxAttempts: 1, backoff: "linear" },
    },
  ],
  origin: { path: "/tests/auth.probitas.ts", line: 5 },
};
console.log(definition);

Name	Description
`name`	Human-readable scenario name (displayed in reports and CLI)
`tags`	Tags for filtering and organizing scenarios.
`steps`	Ordered sequence of entries (resources → setups → steps)
`origin`	Origin where the scenario was defined

Properties

readonlynamestring
Human-readable scenario name (displayed in reports and CLI)

readonlytagsreadonly string[]

Tags for filtering and organizing scenarios.

Tags can be used with the CLI to run specific subsets:

probitas run -s "tag:api"           # Run scenarios tagged "api"
probitas run -s "tag:api,tag:fast"  # Run scenarios with both tags
probitas run -s "!tag:slow"         # Exclude slow scenarios

readonlystepsreadonly StepDefinition[]
Ordered sequence of entries (resources → setups → steps)
readonlyorigin?Origin
Origin where the scenario was defined

interface

#ScenarioMetadata

interface ScenarioMetadata

Serializable scenario metadata (without executable functions).

Used by the JSON reporter and tooling to output scenario information without including non-serializable function references.

Examples

JSON reporter output

{
  "name": "Login Flow",
  "options": { "tags": ["auth"], "stepOptions": { ... } },
  "entries": [
    { "kind": "step", "value": { "name": "Login", "options": { ... } } }
  ],
  "origin": { "path": "/tests/auth.probitas.ts", "line": 5 }
}

Name	Description
`name`	Scenario name
`tags`	Tags for filtering and organizing scenarios.
`steps`	Entry metadata (functions omitted for serialization)
`origin`	Origin where the scenario was defined

Properties

readonlynamestring
Scenario name

readonlytagsreadonly string[]

Tags for filtering and organizing scenarios.

Tags can be used with the CLI to run specific subsets:

probitas run -s "tag:api"           # Run scenarios tagged "api"
probitas run -s "tag:api,tag:fast"  # Run scenarios with both tags
probitas run -s "!tag:slow"         # Exclude slow scenarios

readonlystepsreadonly StepMetadata[]
Entry metadata (functions omitted for serialization)
readonlyorigin?Origin
Origin where the scenario was defined

interface

#ScenarioOptions

interface ScenarioOptions

Configuration options for scenario execution.

Defines metadata and default behavior for an entire scenario.

Examples

const options: ScenarioOptions = {
  tags: ["api", "integration", "slow"],
  stepOptions: {
    timeout: 60000,
    retry: { maxAttempts: 2, backoff: "linear" }
  }
};

Name	Description
`tags`	Tags for filtering and organizing scenarios.
`stepOptions`	Default options applied to all steps in this scenario.

Properties

readonlytags?readonly string[]

Tags for filtering and organizing scenarios.

Tags can be used with the CLI to run specific subsets:

probitas run -s "tag:api"           # Run scenarios tagged "api"
probitas run -s "tag:api,tag:fast"  # Run scenarios with both tags
probitas run -s "!tag:slow"         # Exclude slow scenarios

readonlystepOptions?StepOptions
Default options applied to all steps in this scenario.

Individual steps can override these defaults by specifying their own options in the .step() call.

interface

#StepContext

interface StepContext

Execution context provided to steps, resources, and setup hooks.

The context provides access to:

Previous step results with full type inference
All accumulated results as a typed tuple
Named resources registered with .resource()
Shared storage for cross-step communication
Abort signal for timeout and cancellation handling

Examples

Accessing previous result

import type { StepContext } from "@probitas/core";

// Steps receive context with the previous step's result
const stepFn = (ctx: StepContext) => {
  // ctx.previous contains the result from the previous step
  const prev = ctx.previous as { id: number };
  console.log(prev.id); // Access typed result
};
console.log(stepFn);

Using shared store

import type { StepContext } from "@probitas/core";

// The store is shared across all steps in a scenario
const setupFn = (ctx: StepContext) => {
  ctx.store.set("startTime", Date.now());
};

const stepFn = (ctx: StepContext) => {
  const start = ctx.store.get("startTime") as number;
  console.log(`Elapsed: ${Date.now() - start}ms`);
};
console.log(setupFn, stepFn);

Name	Description
`index`	Current step index (0-based).
`previous`	Result from the previous step.
`results`	All accumulated results as a typed tuple.
`store`	Shared key-value storage for cross-step communication.
`resources`	Named resources registered with `.resource()`.
`signal`	Abort signal that fires on timeout or manual cancellation.

Properties

readonlyindexnumber
Current step index (0-based).

Useful for conditional logic based on position in the scenario.
readonlypreviousunknown
Result from the previous step.

Fully typed based on what the previous step returned. For the first step, this is unknown.

readonlyresultsreadonly unknown[]

All accumulated results as a typed tuple.

Allows accessing any previous result by index:

import type { StepContext } from "@probitas/core";

const stepFn = (ctx: StepContext) => {
  ctx.results[0]; // First step's result
  ctx.results[1]; // Second step's result
};
console.log(stepFn);

readonlystoreMap<string, unknown>
Shared key-value storage for cross-step communication.

Use this for data that doesn't fit the step result pattern, such as metadata or configuration set during setup.

readonlyresourcesRecord<string, unknown>

Named resources registered with .resource().

Resources are typed based on their registration:

import type { StepContext } from "@probitas/core";

interface DbResource {
  query(sql: string): unknown;
}

// Access resources registered with .resource()
const stepFn = (ctx: StepContext) => {
  const db = ctx.resources["db"] as DbResource;
  return db.query("SELECT 1");
};
console.log(stepFn);

readonlysignal?AbortSignal
Abort signal that fires on timeout or manual cancellation.

Pass this to fetch() or other APIs that support AbortSignal for proper timeout handling.

interface

#StepDefinition

interface StepDefinition<T = unknown>

Immutable definition of a scenario step.

Contains all information needed to execute a single step: the step function, its options, and debugging metadata.

Name	Description
`kind`	—
`name`	Human-readable step name (displayed in reports)
`fn`	Step function to execute
`timeout`	Maximum execution time in milliseconds.
`retry`	Retry configuration for handling transient failures
`origin`	Origin where the step was defined (for error messages)

Properties

readonlykind"step" | "resource" | "setup"
readonlynamestring
Human-readable step name (displayed in reports)
readonlyfnStepFunction<T>
Step function to execute
readonlytimeoutnumber
Maximum execution time in milliseconds.

If the step takes longer, a TimeoutError is thrown. Default: 30000 (30 seconds)
readonlyretry{ maxAttempts: number; backoff: "linear" | "exponential" }
Retry configuration for handling transient failures
readonlyorigin?Origin
Origin where the step was defined (for error messages)

interface

#StepOptions

interface StepOptions

Configuration options for individual step execution.

Controls timeout and retry behavior for a step. These options can be set at:

Step level (highest priority)
Scenario level (applies to all steps in scenario)
Default values (30s timeout, no retry)

Examples

const options: StepOptions = {
  timeout: 60000,  // 60 seconds
  retry: {
    maxAttempts: 3,
    backoff: "exponential"  // Waits 1s, 2s, 4s between retries
  }
};

Name	Description
`timeout`	Maximum execution time in milliseconds.
`retry`	Retry configuration for handling transient failures

Properties

readonlytimeout?number
Maximum execution time in milliseconds.

If the step takes longer, a TimeoutError is thrown. Default: 30000 (30 seconds)
readonlyretry?{ maxAttempts?: number; backoff?: "linear" | "exponential" }
Retry configuration for handling transient failures

Types

type

#SetupCleanup

type SetupCleanup = void | unknown | Disposable | AsyncDisposable

Cleanup handler returned by setup functions.

Setup functions can return various cleanup mechanisms that are automatically invoked after the scenario completes (regardless of success or failure).

Supported cleanup patterns:

void / undefined: No cleanup needed
() => void: Synchronous cleanup function
() => Promise<void>: Async cleanup function
Disposable: Object with [Symbol.dispose]() method
AsyncDisposable: Object with [Symbol.asyncDispose]() method

type

#StepFunction

type StepFunction<T = unknown> = (ctx: StepContext) => unknown

Function signature for step execution.

A step function receives the execution context and returns a value (sync or async) that becomes available to subsequent steps.

type

#StepMetadata

type StepMetadata = Omit<StepDefinition, "fn">

Serializable step metadata (without the function).

Used for JSON output, tooling, and inspection without executing code.

Links

Related Packages

Type Definitions

Options Types

Function Types

Loader Utilities

Selector Utilities

Installation

Interfaces

#ScenarioDefinition

Examples

Properties

Links

#ScenarioMetadata

Examples

Properties

Links

#ScenarioOptions

Examples

Properties

Links

#StepContext

Examples

Properties

#StepDefinition

Properties

Links

#StepOptions

Examples

Properties

Types

#SetupCleanup

#StepFunction

Links

#StepMetadata

Links