Remove unnecessary DispatchGroup from tests

Tests/KingfisherTests/ImageViewExtensionTests.swift

@@ -660,35 +660,26 @@ class ImageViewExtensionTests: XCTestCase {
         
         let options: KingfisherOptionsInfo = [.cacheMemoryOnly, .memoryCacheExpiration(.seconds(0.15))]
         
-        let group = DispatchGroup()
-        
-        group.enter()
         imageView.kf.setImage(with: url, options: options) { result in
             XCTAssertNotNil(result.value?.image)
             XCTAssertTrue(result.value!.cacheType == .none)
-            group.leave()
         }
         
-        group.enter()
         delay(0.1) {
             self.imageView.kf.setImage(with: url, options: options) { result in
                 XCTAssertNotNil(result.value?.image)
                 XCTAssertTrue(result.value!.cacheType == .memory)
-                group.leave()
             }
         }
         
-        group.enter()
         delay(0.2) {
             self.imageView.kf.setImage(with: url, options: options) { result in
                 XCTAssertNotNil(result.value?.image)
                 XCTAssertTrue(result.value!.cacheType == .memory)
-                group.leave()
+                exp.fulfill()
             }
         }
         
-        group.notify(queue: .main, execute: exp.fulfill)
-        
         waitForExpectations(timeout: 3, handler: nil)
     }
     
@@ -699,35 +690,26 @@ class ImageViewExtensionTests: XCTestCase {
         
         let options: KingfisherOptionsInfo = [.cacheMemoryOnly, .memoryCacheExpirationNotExtendable, .memoryCacheExpiration(.seconds(0.15))]
   
-        let group = DispatchGroup()
-        
-        group.enter()
         imageView.kf.setImage(with: url, options: options) { result in
             XCTAssertNotNil(result.value?.image)
             XCTAssertTrue(result.value!.cacheType == .none)
-            group.leave()
         }
         
-        group.enter()
         delay(0.1) {
             self.imageView.kf.setImage(with: url, options: options) { result in
                 XCTAssertNotNil(result.value?.image)
                 XCTAssertTrue(result.value!.cacheType == .memory)
-                group.leave()
             }
         }
         
-        group.enter()
         delay(0.2) {
             self.imageView.kf.setImage(with: url, options: options) { result in
                 XCTAssertNotNil(result.value?.image)
                 XCTAssertTrue(result.value!.cacheType == .none)
-                group.leave()
+                exp.fulfill()
             }
         }
         
-        group.notify(queue: .main, execute: exp.fulfill)
-        
         waitForExpectations(timeout: 3, handler: nil)
     }
 }