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# Plugin Integration
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Core plugin registration and validation schema for Stryker integration. Provides the main entry point for using Jest as a test runner in Stryker mutation testing.
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## Capabilities
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### Stryker Plugin Declaration
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The main plugin export that registers Jest as a test runner with Stryker's plugin system.
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```typescript { .api }
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/**
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 * Array of Stryker plugin declarations for Jest test runner
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 * Contains the Jest test runner factory plugin registration
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 */
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export const strykerPlugins: Array<PluginDeclaration>;
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```
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**Usage Example:**
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```typescript
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import { strykerPlugins } from "@stryker-mutator/jest-runner";
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// Plugins are automatically registered when the package is loaded
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// Used internally by Stryker to discover and load the Jest test runner
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console.log(strykerPlugins); // [{ kind: 'TestRunner', name: 'jest', factory: ... }]
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```
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### Validation Schema
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JSON schema for validating Jest runner configuration options.
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```typescript { .api }
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/**
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 * Validation schema for Jest runner options
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 * Loaded from schema/jest-runner-options.json
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 */
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export const strykerValidationSchema: JestRunnerOptionsSchema;
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```
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**Usage Example:**
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```typescript
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import { strykerValidationSchema } from "@stryker-mutator/jest-runner";
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// Schema is used internally by Stryker for configuration validation
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// Contains validation rules for jest configuration options
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console.log(strykerValidationSchema.properties.jest);
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```
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## Types
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### Plugin Declaration Types
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```typescript { .api }
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interface PluginDeclaration {
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  kind: PluginKind.TestRunner;
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  name: 'jest';
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  factory: typeof jestTestRunnerFactory;
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}
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enum PluginKind {
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  TestRunner = 'TestRunner',
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  // ... other plugin types
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}
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```
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### Schema Types
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```typescript { .api }
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interface JestRunnerOptionsSchema {
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  $schema: string;
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  type: 'object';
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  title: 'JestRunnerOptions';
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  additionalItems: boolean;
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  properties: {
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    jest: JestOptionsSchema;
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  };
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  definitions: {
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    jestProjectType: JestProjectTypeSchema;
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  };
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}
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interface JestOptionsSchema {
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  title: 'JestOptions';
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  description: string;
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  type: 'object';
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  default: {};
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  properties: {
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    projectType: { $ref: '#/definitions/jestProjectType' };
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    configFile: { description: string; type: 'string' };
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    config: { description: string; type: 'object' };
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    enableFindRelatedTests: { description: string; type: 'boolean'; default: true };
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  };
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  additionalProperties: boolean;
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}
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```
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## Environment Setup
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The plugin automatically sets up the testing environment:
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```typescript
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// Automatically set when the package is loaded
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process.env.BABEL_ENV = 'test';
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```
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This ensures that Babel transformations are applied correctly for Jest testing within the Stryker environment.
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## Integration with Stryker Core
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The plugin integrates with Stryker through the dependency injection system:
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- **Plugin Discovery**: Stryker discovers Jest runner through `strykerPlugins` export
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- **Factory Creation**: Uses `jestTestRunnerFactory` to create test runner instances  
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- **Validation**: Applies `strykerValidationSchema` to validate Jest configuration
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- **Lifecycle Management**: Handles initialization, execution, and cleanup through the TestRunner interface