[APM] Migrate /correlations to deployment agnostic test (elastic#19…

…9276)

## Summary

Closes elastic#198962
Part of elastic#193245

This PR contains the changes to migrate `correlations` test folder to
Deployment-agnostic testing strategy.

### How to test

- Serverless

```
node scripts/functional_tests_server --config x-pack/test/api_integration/deployment_agnostic/configs/serverless/oblt.serverless.config.ts
node scripts/functional_test_runner --config x-pack/test/api_integration/deployment_agnostic/configs/serverless/oblt.serverless.config.ts --grep="APM"
```

It's recommended to be run against
[MKI](https://github.com/crespocarlos/kibana/blob/main/x-pack/test_serverless/README.md#run-tests-on-mki)

- Stateful
```
node scripts/functional_tests_server --config x-pack/test/api_integration/deployment_agnostic/configs/stateful/oblt.stateful.config.ts
node scripts/functional_test_runner --config x-pack/test/api_integration/deployment_agnostic/configs/stateful/oblt.stateful.config.ts --grep="APM"
```

## Checks

- [ ] (OPTIONAL, only if a test has been unskipped) Run flaky test suite
- [x] local run for serverless
- [x] local run for stateful
- [x] MKI run for serverless

x-pack/test/api_integration/deployment_agnostic/apis/observability/apm/constants/archiver.ts

@@ -0,0 +1,32 @@
+/*
+ * Copyright Elasticsearch B.V. and/or licensed to Elasticsearch B.V. under one
+ * or more contributor license agreements. Licensed under the Elastic License
+ * 2.0; you may not use this file except in compliance with the Elastic License
+ * 2.0.
+ */
+
+type ArchiveName =
+  | '8.0.0'
+  | 'apm_8.0.0'
+  | 'apm_mappings_only_8.0.0'
+  | 'infra_metrics_and_apm'
+  | 'metrics_8.0.0'
+  | 'ml_8.0.0'
+  | 'observability_overview'
+  | 'rum_8.0.0'
+  | 'rum_test_data';
+
+export const ARCHIVER_ROUTES: { [key in ArchiveName]: string } = {
+  '8.0.0': 'x-pack/test/apm_api_integration/common/fixtures/es_archiver/8.0.0',
+  'apm_8.0.0': 'x-pack/test/apm_api_integration/common/fixtures/es_archiver/apm_8.0.0',
+  'apm_mappings_only_8.0.0':
+    'x-pack/test/apm_api_integration/common/fixtures/es_archiver/apm_mappings_only_8.0.0',
+  infra_metrics_and_apm:
+    'x-pack/test/apm_api_integration/common/fixtures/es_archiver/infra_metrics_and_apm',
+  'metrics_8.0.0': 'x-pack/test/apm_api_integration/common/fixtures/es_archiver/metrics_8.0.0',
+  'ml_8.0.0': 'x-pack/test/apm_api_integration/common/fixtures/es_archiver/ml_8.0.0',
+  observability_overview:
+    'x-pack/test/apm_api_integration/common/fixtures/es_archiver/observability_overview',
+  'rum_8.0.0': 'x-pack/test/apm_api_integration/common/fixtures/es_archiver/rum_8.0.0',
+  rum_test_data: 'x-pack/test/apm_api_integration/common/fixtures/es_archiver/rum_test_data',
+};

x-pack/test/api_integration/deployment_agnostic/apis/observability/apm/correlations/failed_transactions.spec.ts

@@ -0,0 +1,236 @@
+/*
+ * Copyright Elasticsearch B.V. and/or licensed to Elasticsearch B.V. under one
+ * or more contributor license agreements. Licensed under the Elastic License
+ * 2.0; you may not use this file except in compliance with the Elastic License
+ * 2.0.
+ */
+
+import { orderBy } from 'lodash';
+import expect from '@kbn/expect';
+import type { FailedTransactionsCorrelationsResponse } from '@kbn/apm-plugin/common/correlations/failed_transactions_correlations/types';
+import { EVENT_OUTCOME } from '@kbn/apm-plugin/common/es_fields/apm';
+import { EventOutcome } from '@kbn/apm-plugin/common/event_outcome';
+import { LatencyDistributionChartType } from '@kbn/apm-plugin/common/latency_distribution_chart_types';
+import type { DeploymentAgnosticFtrProviderContext } from '../../../../ftr_provider_context';
+import { ARCHIVER_ROUTES } from '../constants/archiver';
+
+// These tests go through the full sequence of queries required
+// to get the final results for a failed transactions correlation analysis.
+export default function ApiTest({ getService }: DeploymentAgnosticFtrProviderContext) {
+  const apmApiClient = getService('apmApi');
+  const esArchiver = getService('esArchiver');
+  // This matches the parameters used for the other tab's queries in `../correlations/*`.
+  const getOptions = () => ({
+    environment: 'ENVIRONMENT_ALL',
+    start: '2020',
+    end: '2021',
+    kuery: '',
+  });
+
+  describe('failed transactions', () => {
+    describe('without data', () => {
+      it('handles the empty state', async () => {
+        const overallDistributionResponse = await apmApiClient.readUser({
+          endpoint: 'POST /internal/apm/latency/overall_distribution/transactions',
+          params: {
+            body: {
+              ...getOptions(),
+              percentileThreshold: 95,
+              chartType: LatencyDistributionChartType.failedTransactionsCorrelations,
+            },
+          },
+        });
+
+        expect(overallDistributionResponse.status).to.eql(
+          200,
+          `Expected status to be '200', got '${overallDistributionResponse.status}'`
+        );
+
+        const errorDistributionResponse = await apmApiClient.readUser({
+          endpoint: 'POST /internal/apm/latency/overall_distribution/transactions',
+          params: {
+            body: {
+              ...getOptions(),
+              percentileThreshold: 95,
+              termFilters: [{ fieldName: EVENT_OUTCOME, fieldValue: EventOutcome.failure }],
+              chartType: LatencyDistributionChartType.failedTransactionsCorrelations,
+            },
+          },
+        });
+
+        expect(errorDistributionResponse.status).to.eql(
+          200,
+          `Expected status to be '200', got '${errorDistributionResponse.status}'`
+        );
+
+        const fieldCandidatesResponse = await apmApiClient.readUser({
+          endpoint: 'GET /internal/apm/correlations/field_candidates/transactions',
+          params: {
+            query: getOptions(),
+          },
+        });
+
+        expect(fieldCandidatesResponse.status).to.eql(
+          200,
+          `Expected status to be '200', got '${fieldCandidatesResponse.status}'`
+        );
+
+        const failedTransactionsCorrelationsResponse = await apmApiClient.readUser({
+          endpoint: 'POST /internal/apm/correlations/p_values/transactions',
+          params: {
+            body: {
+              ...getOptions(),
+              fieldCandidates: fieldCandidatesResponse.body?.fieldCandidates,
+            },
+          },
+        });
+
+        expect(failedTransactionsCorrelationsResponse.status).to.eql(
+          200,
+          `Expected status to be '200', got '${failedTransactionsCorrelationsResponse.status}'`
+        );
+
+        const finalRawResponse: FailedTransactionsCorrelationsResponse = {
+          ccsWarning: failedTransactionsCorrelationsResponse.body?.ccsWarning,
+          percentileThresholdValue: overallDistributionResponse.body?.percentileThresholdValue,
+          overallHistogram: overallDistributionResponse.body?.overallHistogram,
+          failedTransactionsCorrelations:
+            failedTransactionsCorrelationsResponse.body?.failedTransactionsCorrelations,
+        };
+
+        expect(finalRawResponse?.failedTransactionsCorrelations?.length).to.eql(
+          0,
+          `Expected 0 identified correlations, got ${finalRawResponse?.failedTransactionsCorrelations?.length}.`
+        );
+      });
+    });
+
+    describe('with data', () => {
+      before(async () => {
+        await esArchiver.load(ARCHIVER_ROUTES['8.0.0']);
+      });
+      after(async () => {
+        await esArchiver.unload(ARCHIVER_ROUTES['8.0.0']);
+      });
+
+      it('runs queries and returns results', async () => {
+        const overallDistributionResponse = await apmApiClient.readUser({
+          endpoint: 'POST /internal/apm/latency/overall_distribution/transactions',
+          params: {
+            body: {
+              ...getOptions(),
+              percentileThreshold: 95,
+              chartType: LatencyDistributionChartType.failedTransactionsCorrelations,
+            },
+          },
+        });
+
+        expect(overallDistributionResponse.status).to.eql(
+          200,
+          `Expected status to be '200', got '${overallDistributionResponse.status}'`
+        );
+
+        const errorDistributionResponse = await apmApiClient.readUser({
+          endpoint: 'POST /internal/apm/latency/overall_distribution/transactions',
+          params: {
+            body: {
+              ...getOptions(),
+              percentileThreshold: 95,
+              termFilters: [{ fieldName: EVENT_OUTCOME, fieldValue: EventOutcome.failure }],
+              chartType: LatencyDistributionChartType.failedTransactionsCorrelations,
+            },
+          },
+        });
+
+        expect(errorDistributionResponse.status).to.eql(
+          200,
+          `Expected status to be '200', got '${errorDistributionResponse.status}'`
+        );
+
+        const fieldCandidatesResponse = await apmApiClient.readUser({
+          endpoint: 'GET /internal/apm/correlations/field_candidates/transactions',
+          params: {
+            query: getOptions(),
+          },
+        });
+
+        expect(fieldCandidatesResponse.status).to.eql(
+          200,
+          `Expected status to be '200', got '${fieldCandidatesResponse.status}'`
+        );
+
+        const fieldCandidates = fieldCandidatesResponse.body?.fieldCandidates.filter(
+          (t) => !(t === EVENT_OUTCOME)
+        );
+
+        // Identified 80 fieldCandidates.
+        expect(fieldCandidates.length).to.eql(
+          80,
+          `Expected field candidates length to be '80', got '${fieldCandidates.length}'`
+        );
+
+        const failedTransactionsCorrelationsResponse = await apmApiClient.readUser({
+          endpoint: 'POST /internal/apm/correlations/p_values/transactions',
+          params: {
+            body: {
+              ...getOptions(),
+              fieldCandidates,
+            },
+          },
+        });
+
+        expect(failedTransactionsCorrelationsResponse.status).to.eql(
+          200,
+          `Expected status to be '200', got '${failedTransactionsCorrelationsResponse.status}'`
+        );
+
+        const fieldsToSample = new Set<string>();
+        if (
+          failedTransactionsCorrelationsResponse.body?.failedTransactionsCorrelations.length > 0
+        ) {
+          failedTransactionsCorrelationsResponse.body?.failedTransactionsCorrelations.forEach(
+            (d) => {
+              fieldsToSample.add(d.fieldName);
+            }
+          );
+        }
+
+        const finalRawResponse: FailedTransactionsCorrelationsResponse = {
+          ccsWarning: failedTransactionsCorrelationsResponse.body?.ccsWarning,
+          percentileThresholdValue: overallDistributionResponse.body?.percentileThresholdValue,
+          overallHistogram: overallDistributionResponse.body?.overallHistogram,
+          errorHistogram: errorDistributionResponse.body?.overallHistogram,
+          failedTransactionsCorrelations:
+            failedTransactionsCorrelationsResponse.body?.failedTransactionsCorrelations,
+        };
+
+        expect(finalRawResponse?.percentileThresholdValue).to.be(1309695.875);
+        expect(finalRawResponse?.errorHistogram?.length).to.be(101);
+        expect(finalRawResponse?.overallHistogram?.length).to.be(101);
+
+        expect(finalRawResponse?.failedTransactionsCorrelations?.length).to.eql(
+          29,
+          `Expected 29 identified correlations, got ${finalRawResponse?.failedTransactionsCorrelations?.length}.`
+        );
+
+        const sortedCorrelations = orderBy(
+          finalRawResponse?.failedTransactionsCorrelations,
+          ['score', 'fieldName', 'fieldValue'],
+          ['desc', 'asc', 'asc']
+        );
+        const correlation = sortedCorrelations?.[0];
+
+        expect(typeof correlation).to.be('object');
+        expect(correlation?.doc_count).to.be(31);
+        expect(correlation?.score).to.be(83.70467673605746);
+        expect(correlation?.bg_count).to.be(31);
+        expect(correlation?.fieldName).to.be('transaction.result');
+        expect(correlation?.fieldValue).to.be('HTTP 5xx');
+        expect(typeof correlation?.pValue).to.be('number');
+        expect(typeof correlation?.normalizedScore).to.be('number');
+        expect(typeof correlation?.failurePercentage).to.be('number');
+        expect(typeof correlation?.successPercentage).to.be('number');
+      });
+    });
+  });
+}

x-pack/test/api_integration/deployment_agnostic/apis/observability/apm/correlations/field_candidates.spec.ts

@@ -0,0 +1,63 @@
+/*
+ * Copyright Elasticsearch B.V. and/or licensed to Elasticsearch B.V. under one
+ * or more contributor license agreements. Licensed under the Elastic License
+ * 2.0; you may not use this file except in compliance with the Elastic License
+ * 2.0.
+ */
+
+import expect from '@kbn/expect';
+import type { DeploymentAgnosticFtrProviderContext } from '../../../../ftr_provider_context';
+import { ARCHIVER_ROUTES } from '../constants/archiver';
+
+export default function ApiTest({ getService }: DeploymentAgnosticFtrProviderContext) {
+  const apmApiClient = getService('apmApi');
+  const esArchiver = getService('esArchiver');
+
+  const endpoint = 'GET /internal/apm/correlations/field_candidates/transactions';
+
+  const getOptions = () => ({
+    params: {
+      query: {
+        environment: 'ENVIRONMENT_ALL',
+        start: '2020',
+        end: '2021',
+        kuery: '',
+      },
+    },
+  });
+
+  describe('field candidates', () => {
+    describe('without data', () => {
+      it('handles the empty state', async () => {
+        const response = await apmApiClient.readUser({
+          endpoint,
+          ...getOptions(),
+        });
+
+        expect(response.status).to.be(200);
+        // If the source indices are empty, there will be no field candidates
+        // because of the `include_empty_fields: false` option in the query.
+        expect(response.body?.fieldCandidates.length).to.be(0);
+      });
+    });
+
+    describe('with data and default args', () => {
+      before(async () => {
+        await esArchiver.load(ARCHIVER_ROUTES['8.0.0']);
+      });
+      after(async () => {
+        await esArchiver.unload(ARCHIVER_ROUTES['8.0.0']);
+      });
+
+      it('returns field candidates', async () => {
+        const response = await apmApiClient.readUser({
+          endpoint,
+          ...getOptions(),
+        });
+
+        expect(response.status).to.eql(200);
+        expect(response.body?.fieldCandidates.length).to.be(81);
+      });
+    });
+  });
+}