Fix memory leaks via auto-unsubscribing and DI

This commit simplifies event handling, providing a unified and robust
way to handle event lifecycling. This way, it fixes events not being
unsubscribed when state is changed.

Introduce a new function in `EventSubscriptionCollection` to remove
existing events and adding new events. This provides an easier to use
API, which leads to code that's easier to understand. It also prevents
potential bugs that may occur due to forgetting to call both functions.
It fixes `TheScriptsMenu` not unregistering events on state change.
Other improvements include:
  - Include a getter to get total amount of registered subcriptions.
    This helps in unit testing.
  - Have nullish checks to prevent potential errors further down the
    execution.
  - Use array instead of rest parameters to increase readability and
    simplify tests.

Ensure `SliderHandler` stops resizes on unmount, unsubscribing from all
events and resetting state to default.

Update `injectionKeys` to do imports as types to avoid circular
dependencies. Simplify importing `injectionKeys` to enable and strict
typings for iterating injection keys.

Add tests covering new behavior.

tests/unit/infrastructure/Events/EventSubscriptionCollection.spec.ts

@@ -1,21 +1,172 @@
 import { describe, it, expect } from 'vitest';
 import { EventSubscriptionCollection } from '@/infrastructure/Events/EventSubscriptionCollection';
+import { EventSubscriptionStub } from '@tests/unit/shared/Stubs/EventSubscriptionStub';
+import { itEachAbsentCollectionValue, itEachAbsentObjectValue } from '@tests/unit/shared/TestCases/AbsentTests';
 import { IEventSubscription } from '@/infrastructure/Events/IEventSource';
 
 describe('EventSubscriptionCollection', () => {
-  it('unsubscribeAll unsubscribes from all registered subscriptions', () => {
-    // arrange
-    const sut = new EventSubscriptionCollection();
-    const expected = ['unsubscribed1', 'unsubscribed2'];
-    const actual = new Array<string>();
-    const subscriptions: IEventSubscription[] = [
-      { unsubscribe: () => actual.push(expected[0]) },
-      { unsubscribe: () => actual.push(expected[1]) },
-    ];
-    // act
-    sut.register(...subscriptions);
-    sut.unsubscribeAll();
-    // assert
-    expect(actual).to.deep.equal(expected);
+  describe('register', () => {
+    it('increments `subscriptionCount` for each registration', () => {
+      // arrange
+      const sut = new EventSubscriptionCollection();
+      const subscriptions = createSubscriptionStubList(2);
+
+      // act
+      sut.register(subscriptions);
+
+      // assert
+      expect(sut.subscriptionCount).to.equal(2);
+    });
+    it('retains the subscribed state of registrations', () => {
+      // arrange
+      const sut = new EventSubscriptionCollection();
+      const subscriptions = createSubscriptionStubList(2);
+
+      // act
+      sut.register(subscriptions);
+
+      // assert
+      expectAllSubscribed(subscriptions);
+    });
+    describe('validation', () => {
+      // arrange
+      const sut = new EventSubscriptionCollection();
+      // act
+      const act = (
+        subscriptions: IEventSubscription[],
+      ) => sut.register(subscriptions);
+      /// assert
+      describeSubscriptionValidations(act);
+    });
+  });
+  describe('unsubscribeAll', () => {
+    it('unsubscribes all registrations', () => {
+      // arrange
+      const sut = new EventSubscriptionCollection();
+      const subscriptions = createSubscriptionStubList(2);
+
+      // act
+      sut.register(subscriptions);
+      sut.unsubscribeAll();
+
+      // assert
+      expectAllUnsubscribed(subscriptions);
+    });
+    it('resets `subscriptionCount` to zero', () => {
+      // arrange
+      const sut = new EventSubscriptionCollection();
+      const subscriptions = createSubscriptionStubList(2);
+      sut.register(subscriptions);
+
+      // act
+      sut.unsubscribeAll();
+
+      // assert
+      expect(sut.subscriptionCount).to.equal(0);
+    });
+  });
+  describe('unsubscribeAllAndRegister', () => {
+    it('unsubscribes all previous registrations', () => {
+      // arrange
+      const sut = new EventSubscriptionCollection();
+      const oldSubscriptions = createSubscriptionStubList(2);
+      sut.register(oldSubscriptions);
+      const newSubscriptions = createSubscriptionStubList(1);
+
+      // act
+      sut.unsubscribeAllAndRegister(newSubscriptions);
+
+      // assert
+      expectAllUnsubscribed(oldSubscriptions);
+    });
+    it('retains the subscribed state of new registrations', () => {
+      // arrange
+      const sut = new EventSubscriptionCollection();
+      const oldSubscriptions = createSubscriptionStubList(2);
+      sut.register(oldSubscriptions);
+      const newSubscriptions = createSubscriptionStubList(2);
+
+      // act
+      sut.unsubscribeAllAndRegister(newSubscriptions);
+
+      // assert
+      expectAllSubscribed(newSubscriptions);
+    });
+    it('updates `subscriptionCount` to match new registration count', () => {
+      // arrange
+      const sut = new EventSubscriptionCollection();
+      const initialSubscriptionAmount = 1;
+      const expectedSubscriptionAmount = 3;
+      const oldSubscriptions = createSubscriptionStubList(initialSubscriptionAmount);
+      sut.register(oldSubscriptions);
+      const newSubscriptions = createSubscriptionStubList(expectedSubscriptionAmount);
+
+      // act
+      sut.unsubscribeAllAndRegister(newSubscriptions);
+
+      // assert
+      expect(sut.subscriptionCount).to.equal(expectedSubscriptionAmount);
+    });
+
+    describe('validation', () => {
+      // arrange
+      const sut = new EventSubscriptionCollection();
+      // act
+      const act = (
+        subscriptions: IEventSubscription[],
+      ) => sut.unsubscribeAllAndRegister(subscriptions);
+      /// assert
+      describeSubscriptionValidations(act);
+    });
   });
 });
+
+function expectAllSubscribed(subscriptions: EventSubscriptionStub[]) {
+  expect(subscriptions.every((subscription) => subscription.isSubscribed)).to.equal(true);
+}
+
+function expectAllUnsubscribed(subscriptions: EventSubscriptionStub[]) {
+  expect(subscriptions.every((subscription) => subscription.isUnsubscribed)).to.equal(true);
+}
+
+function createSubscriptionStubList(amount: number): EventSubscriptionStub[] {
+  if (amount <= 0) {
+    throw new Error(`unexpected amount of subscriptions: ${amount}`);
+  }
+  return Array.from({ length: amount }, () => new EventSubscriptionStub());
+}
+
+function describeSubscriptionValidations(
+  handleValue: (subscriptions: IEventSubscription[]) => void,
+) {
+  describe('throws error if no subscriptions are provided', () => {
+    itEachAbsentCollectionValue((absentValue) => {
+      // arrange
+      const expectedError = 'missing subscriptions';
+
+      // act
+      const act = () => handleValue(absentValue);
+
+      // assert
+      expect(act).to.throw(expectedError);
+    });
+  });
+
+  describe('throws error if nullish subscriptions are provided', () => {
+    itEachAbsentObjectValue((absentValue) => {
+      // arrange
+      const expectedError = 'missing subscription in list';
+      const subscriptions = [
+        new EventSubscriptionStub(),
+        absentValue,
+        new EventSubscriptionStub(),
+      ];
+
+      // act
+      const act = () => handleValue(subscriptions);
+
+      // assert
+      expect(act).to.throw(expectedError);
+    });
+  });
+}