feat(aggregator): add stable integration test pipeline and fix test/runtime config

apps/aggregator/README.md

@@ -517,6 +517,88 @@ const results = this.normalizationService.normalizeMany(rawPrices);
 const { successful, failed } = this.normalizationService.normalizeManyWithErrors(rawPrices);
 ```
 
+## Testing Strategy
+
+The Aggregator service includes comprehensive test coverage for unit and integration testing.
+
+### Test Structure
+
+```
+test/
+├── integration/
+│   └── aggregation-pipeline.integration.spec.ts    # Complete pipeline tests
+```
+
+### Running Tests
+
+**Unit Tests** (default, fast execution):
+```bash
+npm run test                    # Run all unit tests
+npm run test:watch             # Watch mode
+npm run test:cov               # With coverage report
+```
+
+**Integration Tests** (tests complete pipeline):
+```bash
+npm run test:integration       # Run integration tests
+npm run test:integration:cov   # With coverage report
+npm run test:all               # Unit + Integration tests
+```
+
+### Test Coverage
+
+**Unit Tests** (src/**/*.spec.ts):
+- Service isolation and correctness
+- Strategy implementations (Weighted Average, Median, Trimmed Mean)
+- Utility functions
+- Edge cases and error handling
+- Target: >85% coverage
+
+**Integration Tests** (test/integration/):
+- End-to-end normalization pipeline
+- Complete aggregation pipeline
+- Multi-source consensus calculation
+- Confidence metrics computation
+- All aggregation methods comparison
+- Edge cases (single source, empty arrays, many sources)
+- Price spread and volatility scenarios
+
+### Test Scenarios Covered
+
+1. **High Confidence** - Closely agreeing prices from multiple sources
+2. **Volatile Market** - High price spread scenarios
+3. **Single Source** - Graceful handling of minimal data
+4. **Many Sources** - Scalability with 20+ sources
+5. **Different Methods** - Validation of all aggregation strategies
+6. **Complete Pipeline** - Raw → Normalized → Aggregated flow
+
+### Running Integration Tests
+
+```bash
+# Run integration tests with single-threaded execution
+npm run test:integration
+
+# Run with coverage
+npm run test:integration:cov
+
+# Run specific test file
+npm run test:integration -- aggregation-pipeline.integration.spec
+
+# Watch mode
+npm run test:integration -- --watch
+```
+
+### Test Output
+
+Integration tests validate:
+- ✅ Normalization correctness
+- ✅ Confidence scoring (high vs volatile scenarios)
+- ✅ Weighted average aggregation
+- ✅ Median aggregation
+- ✅ Trimmed mean aggregation
+- ✅ Multi-source extraction
+- ✅ End-to-end pipeline
+
 ## Status
 
 🚧 Under construction - Aggregation and filtering logic will be implemented in subsequent issues.

apps/aggregator/jest.integration.config.js

@@ -0,0 +1,15 @@
+module.exports = {
+  displayName: 'aggregator-integration',
+  preset: 'ts-jest',
+  testEnvironment: 'node',
+  rootDir: '.',
+  testMatch: [
+    '**/test/integration/**/*.integration.spec.ts',
+  ],
+  moduleFileExtensions: ['js', 'json', 'ts'],
+  moduleNameMapper: {
+    '^@oracle-stocks/shared$': '<rootDir>/../../packages/shared/src',
+    '^@oracle-stocks/shared/(.*)$': '<rootDir>/../../packages/shared/src/$1',
+  },
+  testTimeout: 30000,
+};

apps/aggregator/package.json

@@ -13,6 +13,10 @@
     "test": "jest",
     "test:watch": "jest --watch",
     "test:cov": "jest --coverage",
+    "test:integration": "jest --config jest.integration.config.js --runInBand",
+    "test:integration:cov": "jest --config jest.integration.config.js --coverage --runInBand",
+    "test:e2e": "jest --config jest.integration.config.js --testPathPattern=e2e --runInBand",
+    "test:all": "npm run test && npm run test:integration",
     "check-types": "tsc --noEmit"
   },
   "dependencies": {
@@ -63,6 +67,9 @@
     ],
     "rootDir": "src",
     "testRegex": ".*\\.spec\\.ts$",
+    "testPathIgnorePatterns": [
+      "<rootDir>/../test/"
+    ],
     "transform": {
       "^.+\\.(t|j)s$": "ts-jest"
     },

apps/aggregator/src/app.module.ts

@@ -2,9 +2,6 @@ import { Module } from '@nestjs/common';
 import { NormalizationModule } from './modules/normalization.module';
 import { ConfigModule } from '@nestjs/config';
 import { AggregationService } from './services/aggregation.service';
-import { WeightedAverageAggregator } from './strategies/aggregators/weighted-average.aggregator';
-import { MedianAggregator } from './strategies/aggregators/median.aggregator';
-import { TrimmedMeanAggregator } from './strategies/aggregators/trimmed-mean.aggregator';
 import { HealthModule } from './health/health.module';
 import { MetricsModule } from './metrics/metrics.module';
 import { DebugModule } from './debug/debug.module';
@@ -29,9 +26,6 @@ import { DataReceptionService } from './services/data-reception.service';
   providers: [
     DataReceptionService,
     AggregationService,
-    WeightedAverageAggregator,
-    MedianAggregator,
-    TrimmedMeanAggregator,
   ],
   exports: [AggregationService],
 })