diff --git a/.github/copilot-instructions.md b/.github/copilot-instructions.md
new file mode 100644
index 0000000..46a0b74
--- /dev/null
+++ b/.github/copilot-instructions.md
@@ -0,0 +1,24 @@
+# Copilot instructions for this repository
+
+Preferred behavior for running backend tests and quality checks:
+
+- Always run backend tests and QA inside the docker-compose "app" service so environment, PHP extensions and dependencies match the container.
+- Prefer using the Makefile targets which already invoke the app service. Examples:
+  - make test        # runs phpunit inside the app container
+  - make quality     # runs composer qa inside the app container
+
+If running commands directly inside the container, run non-interactively (no -it) to avoid TTY allocation issues:
+
+- docker compose exec -T app bin/phpunit
+- docker compose exec -T app composer qa
+- docker compose exec -T app vendor/bin/phpstan analyse --memory-limit=1G
+- docker compose exec -T app vendor/bin/php-cs-fixer fix
+- docker compose exec -T app vendor/bin/deptrac analyse --report-uncovered
+
+Guidelines for Copilot CLI usage in this repo:
+
+- When asked to run tests or QA, prefer the Makefile targets (make test, make quality) executed in the repository root.
+- If running inside a container is required, always target the "app" service and use `-T` for exec to run non-interactively.
+- When proposing automation or CI commands, include explicit container commands using the "app" service so they work in the project's docker-compose setup.
+
+These instructions ensure consistent, reproducible test and QA runs by using the project's containerized environment.
diff --git a/backend/tests/Unit/SplitFairly/ExpenseTrackerTest.php b/backend/tests/Unit/SplitFairly/ExpenseTrackerTest.php
new file mode 100644
index 0000000..9ee6ebe
--- /dev/null
+++ b/backend/tests/Unit/SplitFairly/ExpenseTrackerTest.php
@@ -0,0 +1,46 @@
+<?php
+
+declare(strict_types=1);
+
+namespace App\Tests\Unit\SplitFairly;
+
+use App\SplitFairly\CurrentUserInterface;
+use App\SplitFairly\Event;
+use App\SplitFairly\EventStoreInterface;
+use App\SplitFairly\Expense;
+use App\SplitFairly\ExpenseTracker;
+use App\SplitFairly\NormalizerInterface;
+use App\SplitFairly\Price;
+use PHPUnit\Framework\TestCase;
+
+final class ExpenseTrackerTest extends TestCase
+{
+    public function test_tracks_expense_and_persists_event(): void
+    {
+        $price = new Price(value: 10.50, currency: 'EUR');
+        $expense = new Expense(price: $price, what: 'Coffee', type: 'Groceries', location: 'Starbucks');
+
+        $currentUser = $this->createMock(CurrentUserInterface::class);
+        $currentUser->method('getUuid')->willReturn('user-123');
+
+        $normalizedPayload = ['price' => (string) $price, 'what' => 'Coffee', 'type' => 'Groceries', 'location' => 'Starbucks'];
+        $normalizer = $this->createMock(NormalizerInterface::class);
+        $normalizer->expects($this->once())->method('toArray')->with($expense, ['id'])->willReturn($normalizedPayload);
+
+        $eventStore = $this->createMock(EventStoreInterface::class);
+        $eventStore->expects($this->once())->method('persist')->with(
+            $this->callback(function (Event $event) use ($expense, $normalizedPayload): bool {
+                return 'user-123' === $event->createdBy
+                    && 'Expense' === $event->subjectType
+                    && $event->subjectId === $expense->getId()->toRfc4122()
+                    && 'tracked' === $event->eventType
+                    && $event->payload === $normalizedPayload;
+            }),
+            false
+        );
+
+        $tracker = new ExpenseTracker($eventStore, $normalizer, $currentUser);
+
+        $tracker->track($expense);
+    }
+}
diff --git a/codecov.yml b/codecov.yml
new file mode 100644
index 0000000..c56d6ac
--- /dev/null
+++ b/codecov.yml
@@ -0,0 +1,14 @@
+# Limit Codecov reports to the SplitFairly namespace
+coverage:
+  status:
+    project:
+      default:
+        target: 0
+  precision: 2
+  round: down
+reports:
+  - name: SplitFairly
+    paths:
+      - backend/src/SplitFairly
+    # Only show this report on the Codecov UI
+    # see https://docs.codecov.com/docs/codecov-yaml#section-reports
diff --git a/dashboard/assets/config.yml b/dashboard/assets/config.yml
index 4f31dfe..fec8b10 100644
--- a/dashboard/assets/config.yml
+++ b/dashboard/assets/config.yml
@@ -49,3 +49,8 @@ services:
         icon: "fa-brands fa-github"
         url: "https://github.com/makomweb/split-fairly"
         target: "_blank"
+      - name: "Code coverage"
+        subtitle: "PHPUnit coverage"
+        icon: "fa-solid fa-clipboard-check"
+        url: "http://localhost:8000/coverage/index.html"
+        target: "_blank"
diff --git a/docker-compose.yaml b/docker-compose.yaml
index 19dd6ea..b797067 100644
--- a/docker-compose.yaml
+++ b/docker-compose.yaml
@@ -79,7 +79,7 @@ services:
         volumes:
             - ./dashboard/assets:/www/assets
             - ./backend/report:/www/public/report
-            - ./backend/coverage:/www/public/coverage
+            - ./backend/coverage:/www/coverage
         ports:
             - "8000:8080"
         user: "1000:1001"