Add self-tests for assert[Not]Equals() with arrays

Author: sormuras

junit-jupiter-api/src/main/java/org/junit/jupiter/api/AssertionUtils.java

@@ -18,6 +18,8 @@
 
 import org.jspecify.annotations.Nullable;
 import org.junit.platform.commons.annotation.Contract;
+import org.junit.platform.commons.logging.Logger;
+import org.junit.platform.commons.logging.LoggerFactory;
 import org.junit.platform.commons.util.UnrecoverableExceptions;
 
 /**
@@ -28,6 +30,8 @@
  */
 class AssertionUtils {
 
+	private static final Logger logger = LoggerFactory.getLogger(AssertionUtils.class);
+
 	private AssertionUtils() {
 		/* no-op */
 	}
@@ -129,6 +133,10 @@ static boolean objectsAreEqual(@Nullable Object obj1, @Nullable Object obj2) {
 		if (obj1 == null) {
 			return (obj2 == null);
 		}
+		if (obj1.getClass().isArray() && (obj2 != null && obj2.getClass().isArray())) {
+			// TODO Find first method in user's code, i.e. non-framework code.
+			logger.debug(() -> "Should have used `assertArrayEquals()` in method: <TODO>");
+		}
 		return obj1.equals(obj2);
 	}
 

jupiter-tests/src/test/java/org/junit/jupiter/api/AssertEqualsAssertionsTests.java

@@ -13,12 +13,18 @@
 import static org.junit.jupiter.api.AssertionTestUtils.assertExpectedAndActualValues;
 import static org.junit.jupiter.api.AssertionTestUtils.assertMessageEndsWith;
 import static org.junit.jupiter.api.AssertionTestUtils.assertMessageEquals;
+import static org.junit.jupiter.api.AssertionTestUtils.assertMessageMatches;
 import static org.junit.jupiter.api.AssertionTestUtils.assertMessageStartsWith;
 import static org.junit.jupiter.api.AssertionTestUtils.expectAssertionFailedError;
 import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertLinesMatch;
 import static org.junit.jupiter.api.Assertions.assertThrows;
 
+import java.util.logging.LogRecord;
+
+import org.junit.jupiter.api.fixtures.TrackLogRecords;
 import org.junit.jupiter.api.function.Executable;
+import org.junit.platform.commons.logging.LogRecordListener;
 import org.opentest4j.AssertionFailedError;
 
 /**
@@ -750,6 +756,35 @@ void chars() {
 
 	}
 
+	@Nested
+	class ArraysAsArguments {
+		@Test
+		void objects(@TrackLogRecords LogRecordListener listener) {
+			Object object = new Object();
+			Object array1 = new Object[] { object };
+			Object array2 = new Object[] { object };
+			try {
+				assertEquals(array1, array2);
+				expectAssertionFailedError();
+			}
+			catch (AssertionFailedError ex) {
+				assertMessageMatches(ex, "expected: " + //
+						"\\Q[Ljava.lang.Object;@\\E" + //
+						".+" + //
+						"\\Q<[java.lang.Object@\\E" + //
+						".+" + //
+						"\\Q]> but was: [Ljava.lang.Object;@\\E" + //
+						".+" + //
+						"\\Q<[java.lang.Object@\\E" + //
+						".+" + //
+						"\\Q]>\\E");
+			}
+			assertLinesMatch("""
+					Should have used `assertArrayEquals()` in method: <TODO>
+					""".lines(), listener.stream(AssertionUtils.class).map(LogRecord::getMessage));
+		}
+	}
+
 	// -------------------------------------------------------------------------
 
 	@SuppressWarnings("overrides")

jupiter-tests/src/test/java/org/junit/jupiter/api/AssertNotEqualsAssertionsTests.java

@@ -14,9 +14,14 @@
 import static org.junit.jupiter.api.AssertionTestUtils.assertMessageEquals;
 import static org.junit.jupiter.api.AssertionTestUtils.assertMessageStartsWith;
 import static org.junit.jupiter.api.AssertionTestUtils.expectAssertionFailedError;
+import static org.junit.jupiter.api.Assertions.assertLinesMatch;
 import static org.junit.jupiter.api.Assertions.assertNotEquals;
 import static org.junit.jupiter.api.Assertions.assertThrows;
 
+import java.util.logging.LogRecord;
+
+import org.junit.jupiter.api.fixtures.TrackLogRecords;
+import org.junit.platform.commons.logging.LogRecordListener;
 import org.opentest4j.AssertionFailedError;
 
 /**
@@ -624,6 +629,20 @@ void assertNotEqualsInvokesEqualsMethodForIdenticalObjects() {
 
 	}
 
+	@Nested
+	class AssertNotEqualsArrays {
+		@Test
+		void objects(@TrackLogRecords LogRecordListener listener) {
+			Object object = new Object();
+			Object array1 = new Object[] { object };
+			Object array2 = new Object[] { object };
+			assertNotEquals(array1, array2);
+			assertLinesMatch("""
+					Should have used `assertArrayEquals()` in method: <TODO>
+					""".lines(), listener.stream(AssertionUtils.class).map(LogRecord::getMessage));
+		}
+	}
+
 	// -------------------------------------------------------------------------
 
 	@Nested