Use assertThatObject to save casting

Update tests that use `assertThat((Object) ...)` to use the convenience
`assertThatObject(...)` method instead.

Issue gh-8945

core/src/test/java/org/springframework/security/concurrent/AbstractDelegatingSecurityContextScheduledExecutorServiceTests.java

@@ -23,7 +23,7 @@ import org.junit.Before;
 import org.junit.Test;
 import org.mockito.Mock;
 
-import static org.assertj.core.api.Assertions.assertThat;
+import static org.assertj.core.api.Assertions.assertThatObject;
 import static org.mockito.BDDMockito.given;
 import static org.mockito.Mockito.verify;
 
@@ -56,7 +56,7 @@ public abstract class AbstractDelegatingSecurityContextScheduledExecutorServiceT
 		given((ScheduledFuture<Object>) this.delegate.schedule(this.wrappedRunnable, 1, TimeUnit.SECONDS))
 				.willReturn(this.expectedResult);
 		ScheduledFuture<?> result = this.executor.schedule(this.runnable, 1, TimeUnit.SECONDS);
-		assertThat((Object) result).isEqualTo(this.expectedResult);
+		assertThatObject(result).isEqualTo(this.expectedResult);
 		verify(this.delegate).schedule(this.wrappedRunnable, 1, TimeUnit.SECONDS);
 	}
 
@@ -64,7 +64,7 @@ public abstract class AbstractDelegatingSecurityContextScheduledExecutorServiceT
 	public void scheduleCallable() {
 		given(this.delegate.schedule(this.wrappedCallable, 1, TimeUnit.SECONDS)).willReturn(this.expectedResult);
 		ScheduledFuture<Object> result = this.executor.schedule(this.callable, 1, TimeUnit.SECONDS);
-		assertThat((Object) result).isEqualTo(this.expectedResult);
+		assertThatObject(result).isEqualTo(this.expectedResult);
 		verify(this.delegate).schedule(this.wrappedCallable, 1, TimeUnit.SECONDS);
 	}
 
@@ -74,7 +74,7 @@ public abstract class AbstractDelegatingSecurityContextScheduledExecutorServiceT
 		given((ScheduledFuture<Object>) this.delegate.scheduleAtFixedRate(this.wrappedRunnable, 1, 2, TimeUnit.SECONDS))
 				.willReturn(this.expectedResult);
 		ScheduledFuture<?> result = this.executor.scheduleAtFixedRate(this.runnable, 1, 2, TimeUnit.SECONDS);
-		assertThat((Object) result).isEqualTo(this.expectedResult);
+		assertThatObject(result).isEqualTo(this.expectedResult);
 		verify(this.delegate).scheduleAtFixedRate(this.wrappedRunnable, 1, 2, TimeUnit.SECONDS);
 	}
 
@@ -84,7 +84,7 @@ public abstract class AbstractDelegatingSecurityContextScheduledExecutorServiceT
 		given((ScheduledFuture<Object>) this.delegate.scheduleWithFixedDelay(this.wrappedRunnable, 1, 2,
 				TimeUnit.SECONDS)).willReturn(this.expectedResult);
 		ScheduledFuture<?> result = this.executor.scheduleWithFixedDelay(this.runnable, 1, 2, TimeUnit.SECONDS);
-		assertThat((Object) result).isEqualTo(this.expectedResult);
+		assertThatObject(result).isEqualTo(this.expectedResult);
 		verify(this.delegate).scheduleWithFixedDelay(this.wrappedRunnable, 1, 2, TimeUnit.SECONDS);
 	}