docs(test-insights): Add Test Insights documentation section

src/content/docs/test-insights/detection.mdx

@@ -0,0 +1,74 @@
+---
+title: Detection
+description: Identify and prioritize unhealthy tests across your repositories.
+---
+
+Even with prevention in place, tests can degrade over time. Detection surfaces
+all unhealthy tests (flaky and broken) across your repositories, so you can
+see the full picture and prioritize what to fix.
+
+## How tests are classified
+
+Mergify classifies tests based on their results across multiple CI runs,
+with recent results weighted more heavily:
+
+- **Flaky**: The test produces inconsistent results on the same commit. It
+  passes on some runs and fails on others, without any code changes.
+
+- **Broken**: The test fails consistently. Recent runs are weighted more
+  heavily, so a test that started failing recently will be classified as
+  broken even if it passed in earlier runs.
+
+Only unhealthy tests (flaky or broken) appear in Detection. Healthy tests
+are not listed.
+
+## Understanding confidence
+
+Confidence indicates how much data is available to assess a test's health.
+
+- **High confidence**: Enough runs have been collected to make a reliable
+  assessment. The health status is unlikely to change significantly.
+
+- **Low confidence**: Limited data is available. The health status could
+  still shift as more runs are collected. Treat low-confidence results as
+  preliminary.
+
+Confidence increases as more CI runs are collected for a given test.
+
+## Prioritizing with impact
+
+The impact metric reflects how many failed executions a test causes. A
+high-impact flaky test wastes more CI time and disrupts more workflows than
+a low-impact one.
+
+Use impact to decide which tests to fix first: high-impact tests give you
+the most return on investment when fixed.
+
+## Practical workflows
+
+### Finding your worst tests
+
+Sort by impact to surface the tests causing the most CI disruption. These
+are the best candidates for immediate attention.
+
+### Narrowing scope
+
+Use filters to focus on specific areas:
+
+- **Test name**: Search for a specific test or pattern
+- **Job name**: Focus on tests within a particular CI job
+- **Pipeline name**: Narrow to a specific CI pipeline
+
+### Checking quarantine status
+
+Tests that have already been quarantined are indicated in the health status.
+This helps you avoid spending time investigating tests that are already being
+managed through [Mitigation](/test-insights/mitigation).
+
+## Setup
+
+Detection requires test metrics collection through repeated CI runs. See the
+CI setup guides for your platform:
+
+- [GitHub Actions setup](/ci-insights/setup/github-actions)
+- [Jenkins setup](/ci-insights/setup/jenkins)

src/content/docs/test-insights/mitigation.mdx

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+---
+title: Mitigation
+description: Quarantine problematic tests to unblock CI without losing visibility.
+---
+
+When a flaky or broken test blocks CI, teams face a tough choice: fix it
+immediately, delete it, or ignore it. Quarantine offers a better option. The
+test keeps running, but its failures no longer block merges. You maintain full
+visibility without disruption.
+
+## How quarantine works
+
+A quarantined test still executes in your CI pipeline and its results are
+still collected by Mergify. The difference is that failures are ignored for
+merge decisions.
+
+This means:
+
+- Your CI stays green while you work on a fix
+
+- Historical data is preserved, so you can track whether the test improves
+  or worsens over time
+
+- Other team members can see the test is quarantined and why
+
+Quarantine works on any branch, not just the default branch.
+
+:::note
+  Quarantined tests must still be uploaded through one of the supported CI
+  integrations. See the
+  [test framework configuration](/ci-insights#test-framework-configuration)
+  for setup details.
+:::
+
+## Manual quarantine
+
+You can manually add or remove specific tests from quarantine through the
+Mergify dashboard. This is useful when you've identified a problematic test
+through [Detection](/test-insights/detection) and want to stop it from
+blocking your team while you investigate.
+
+For technical details on how quarantine integrates with your CI pipeline,
+see the [Quarantine documentation](/ci-insights/quarantine).
+
+## Auto-quarantine
+
+Auto-quarantine lets Mergify automatically quarantine broken tests. When
+enabled, tests that are classified as broken are quarantined without manual
+intervention.
+
+This is useful for teams that want hands-off management of consistently
+failing tests. You can enable or disable auto-quarantine per repository
+from the Mitigation page in the dashboard.
+
+## Practical workflows
+
+### Quarantining a test from Detection
+
+When you identify a high-impact flaky or broken test in
+[Detection](/test-insights/detection), you can quarantine it directly to
+stop it from blocking merges while you work on a fix.
+
+### Reviewing quarantined tests
+
+Periodically check the Mitigation page to review quarantined tests. Look
+for tests whose health status has improved; these may be ready to be
+removed from quarantine.
+
+### Enabling auto-quarantine
+
+For repositories where broken tests frequently block CI, enable
+auto-quarantine to let Mergify handle it automatically. This reduces manual
+overhead and keeps your CI pipeline moving.
+
+## Setup
+
+Mitigation uses the same CI integration as Detection. To ensure quarantine
+works correctly, your CI must be configured to check quarantine status. See
+the [Quarantine documentation](/ci-insights/quarantine) for technical setup
+details.

src/content/docs/test-insights/prevention.mdx

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+---
+title: Prevention
+description: Catch flaky and broken tests on pull requests before they reach your codebase.
+---
+
+Prevention monitors tests introduced or modified in pull requests. By
+rerunning tests on PRs, it detects flaky behavior before code merges, keeping
+your codebase reliable.
+
+## How it works
+
+When a pull request runs tests, Mergify reruns them to check for consistency.
+Tests that produce different results on the same commit are flagged as flaky.
+This happens transparently as part of your existing CI pipeline, with no changes
+to your test code needed.
+
+Tests caught as flaky on a PR are prevented from silently degrading your
+test suite. You can review their health status before deciding to merge.
+
+## What you can track
+
+Prevention provides key metrics to help you understand test reliability
+on pull requests:
+
+### Caught flaky tests
+
+The number of flaky tests detected during PR reruns. This is the core value
+of Prevention: every caught test is a reliability problem that didn't make it
+into your codebase.
+
+### New tests
+
+Tests being introduced on PRs, along with their health status. Each new test
+is classified as healthy, flaky, or broken based on its rerun results. This
+helps you spot unreliable tests before they're merged.
+
+### CI budget spent
+
+The total CI time spent on reruns. This metric helps teams understand the
+cost of flaky test prevention and make informed trade-offs between
+thoroughness and CI budget.
+
+## Practical workflows
+
+### Reviewing tests before merging
+
+When a PR introduces or modifies tests, check the Prevention page to see
+their health status. Tests with a flaky or broken status should be
+investigated before merging.
+
+### Filtering by pull request state
+
+Use the pull request state filter to focus on specific PRs:
+
+- **Open**: Tests on PRs still in review
+- **Merged**: Tests on PRs that have already been merged
+- **Closed**: Tests on PRs that were closed without merging
+
+### Understanding confidence on new tests
+
+New tests have limited run data, so their confidence level may be low. A low
+confidence means the health status could change as more data is collected.
+Consider waiting for more runs before drawing conclusions about a test's
+reliability.
+
+## Setup
+
+Prevention requires test framework plugins that instrument test runs to track
+flakiness on pull requests.
+
+See the [test framework configuration](/ci-insights#test-framework-configuration)
+for setup instructions specific to your framework (pytest-mergify,
+rspec-mergify, etc.).

src/content/docs/test-insights/test-insights.mdx

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+---
+title: Test Insights
+description: Monitor, detect, and manage unreliable tests across your repositories.
+---
+
+Test Insights helps you manage test reliability across the full lifecycle.
+It catches flaky tests on pull requests before they merge, surfaces unhealthy
+tests across your repositories, and lets you quarantine problematic tests so
+they don't block your CI pipeline.
+
+## How it works
+
+Test Insights is organized into three phases that follow the natural lifecycle
+of a test reliability problem:
+
+1. **[Prevention](/test-insights/prevention)**: Catch flaky and broken tests
+   on pull requests before they reach your codebase. Mergify reruns tests on
+   PRs to detect inconsistent behavior early.
+
+2. **[Detection](/test-insights/detection)**: Identify and prioritize
+   unhealthy tests across your repositories. See which tests are flaky or
+   broken, and focus on the ones with the most impact.
+
+3. **[Mitigation](/test-insights/mitigation)**: Quarantine problematic tests
+   to unblock CI without removing them. Tests keep running, but their failures
+   no longer block merges.
+
+## Key concepts
+
+- **Flaky test**: A test that produces different results on the same commit.
+  For example, passing on one run and failing on the next with identical code.
+
+- **Broken test**: A test that fails consistently, with recent runs weighted
+  more heavily.
+
+- **Health status**: A test's reliability classification: healthy, flaky, or
+  broken. Based on results from multiple CI runs.
+
+- **Confidence**: How much data is available to assess a test's health. Low
+  confidence means the status could still change significantly as more runs
+  are collected.
+
+- **Quarantine**: Isolating a test so its failures are ignored for merge
+  decisions. The test still runs and results are still collected, preserving
+  full visibility.
+
+## Setup
+
+Test Insights is powered by the same CI integration as
+[CI Insights](/ci-insights). To get started, configure your CI system and test
+framework:
+
+- [GitHub Actions setup](/ci-insights/setup/github-actions)
+- [Jenkins setup](/ci-insights/setup/jenkins)
+- [Test framework configuration](/ci-insights#test-framework-configuration)

src/content/navItems.tsx

@@ -100,6 +100,17 @@ const navItems: NavItem[] = [
       },
     ],
   },
+  {
+    title: 'Test Insights',
+    path: '/test-insights',
+    icon: 'fa6-solid:flask-vial',
+    children: [
+      { title: 'Overview', path: '/test-insights', icon: 'fa6-regular:lightbulb' },
+      { title: 'Prevention', path: '/test-insights/prevention', icon: 'fa6-solid:shield-halved' },
+      { title: 'Detection', path: '/test-insights/detection', icon: 'fa6-solid:magnifying-glass' },
+      { title: 'Mitigation', path: '/test-insights/mitigation', icon: 'fa-solid:radiation' },
+    ],
+  },
   {
     title: 'Merge Queue',
     icon: MergeQueueIcon,