add EventEmitterTests

Author: grdsdev

Tests/HelpersTests/EventEmitterTests.swift

@@ -0,0 +1,67 @@
+//
+//  EventEmitterTests.swift
+//  Supabase
+//
+//  Created by Guilherme Souza on 15/10/24.
+//
+
+import ConcurrencyExtras
+import XCTest
+
+@testable import Helpers
+
+final class EventEmitterTests: XCTestCase {
+
+  func testBasics() {
+    let sut = EventEmitter(initialEvent: "0")
+    XCTAssertTrue(sut.emitsLastEventWhenAttaching)
+
+    XCTAssertEqual(sut.lastEvent, "0")
+
+    let receivedEvents = LockIsolated<[String]>([])
+
+    let tokenA = sut.attach { value in
+      receivedEvents.withValue { $0.append("a" + value) }
+    }
+
+    let tokenB = sut.attach { value in
+      receivedEvents.withValue { $0.append("b" + value) }
+    }
+
+    sut.emit("1")
+    sut.emit("2")
+    sut.emit("3")
+    sut.emit("4")
+
+    sut.emit("5", to: tokenA)
+    sut.emit("6", to: tokenB)
+
+    tokenA.cancel()
+
+    sut.emit("7")
+    sut.emit("8")
+
+    XCTAssertEqual(sut.lastEvent, "8")
+
+    XCTAssertEqual(
+      receivedEvents.value,
+      ["a0", "b0", "a1", "b1", "a2", "b2", "a3", "b3", "a4", "b4", "a5", "b6", "b7", "b8"]
+    )
+  }
+
+  func test_dontEmitLastEventWhenAttaching() {
+    let sut = EventEmitter(initialEvent: "0", emitsLastEventWhenAttaching: false)
+    XCTAssertFalse(sut.emitsLastEventWhenAttaching)
+
+    let receivedEvent = LockIsolated<[String]>([])
+    let token = sut.attach { value in
+      receivedEvent.withValue { $0.append(value) }
+    }
+
+    sut.emit("1")
+
+    XCTAssertEqual(receivedEvent.value, ["1"])
+
+    token.cancel()
+  }
+}